HOYA Pottsii - Cubits

Volume 2, #1 Winter, 2008 

1

contents 

Editor's Note --------------------------------------------------------------------------3 

A Look at Dischidia by Antone Jones------------------------------------------4 

Photography, photos and text by Ed Gilding----------------------------------18 

Reprint: Hoya Pottsii from Curtis’ Botanical Magazine------------------21 

Hoya Pottsii Traill by Mark Randal------------------------------------------------24 

Department of Corrections, MR--------------------------------------------33 

Source Materials-------------------------------------------------------------------33 

Glossary--------------------------------------------------------------------------------34 

Appendix A: Lectotype of Hoya subquintuplinervis Miq. (Teysmann #6037) ------35 

Appendix B: Illustration of Hoya griffithii Hook f. from the Botanical Magazine-----36 

Back Page: Hoya griffithii Hook. f. by Torill Nyhuus-----------------------37 

Editor: Mark Randal 

Editor of Dischidia Content: Antone Jones 

Technical Consultant: Bobby Fisher 

Stemma Godmother: Carol Noel 

Usage Policy: Stemma may be distributed freely as a whole, but content and photos remain 

the intellectual property of the individual contributor and may not be reproduced 

separately. Use of any portion of Stemma (including photographic content) for commercial 

gain is strictly prohibited. 

2

Editor's Note 

Bonjour! 

Stemma is pleased to note that we are no longer the only organization in the Hoya world 

publishing digitally. Joining in this past summer (2007) is Asclep-Hoya, the revue of the 

AFAHO, the Association Francophone Des Amateurs De Hoya. The revue is published 

quarterly, and is one of the benefits of membership in this French language society. 

Another perk is the online French Hoya forum Monforums, on the web at: 

http://hoyas.monforum.fr/index.php 

Photographs taken by AFAHO members are 

viewable online at the innovative website Flickr, a 

photo sharing resource: 

www.flickr.com/groups/hoyasmonforumfr 

Another Flickr pool with AFAHO content, open 

to the larger Hoya growing community: 

www.flickr.com/groups/hoyas/pool 

Membership information for the AFAHO may be 

obtained by contacting Alexandre Gavrus at: 

email: kl55555@club-internet.fr 

Please place “AFAHO” in the subject header. n 

Left: 

Photographs of Hoya praetorii Miq. from the Asclep-Hoya 

revue no. 1 

_________________________ 

3

A Look at Dischidia 

Text and all photos by Antone Jones 

(Antone is on-line at www.dischidia.com) 

Flowers of Dischidia sp. Geri 

Some of you are probably thinking to yourself, "Well... the title seems to be missing 

the word, Hoya." You'd be correct. In this article we are going to take an in 

depth look at the genus, Dischidia. We will uncover some of the mysteries that surround 

this sister genus of plants. So, go check on your plants and when you return, 

sit back, relax and enjoy the ride. 

4

General Info 

Dischidia was first described by R. 

Brown in 1810. The type species for 

the genus is the ever common and 

widespread Dischidia nummularia R. 

Br. (pictured at right) which is also 

known as the Button Orchid Plant. 

The genus Dischidia currently comprises 

approximately 80 species all 

of which are epiphytic. They are 

found throughout SE Asia stretching 

from India (D. bengalensis) all the 

way to Australia (D. nummularia). 

Dischidia can be found in the wild 

growing along side Hoya, often times occupying the same tree or even the same 

branch. Many species are myrmecodial (growing with ants) and have developed 

special foliage to accommodate their six legged friends. They can be found at sea 

level all the way up to over 2000m above sea level (Dischidia astephana). 

Presently there are three recognized sections of the genus: Ascidiophora, Conchophyllum 

and Dischidia. Sect. Ascidiophora contains the pitcher leaved species 

i.e., Dischidia major, D. vidalii, and D. complex (D. vidalii pictured). These pitcher 

leaves are utilized by arboreal ants for various things from a place to store larva to a 

waste facility. The pitcher leaves obtain nutrient from the ants by a single root that 

grows and spreads throughout the 

inside of the pitcher leaf. This is a 

great example of a symbiotic relationship; 

the ants get shelter and the 

plant receives nourishment. It has 

also been suggested that the pitcher 

leaves of D. major can also serve as 

a water reservoir if they are growing 

upside down. This would allow water 

retention when rain falls and collects 

inside the leaf. 

5

Top Left: D. diphylla, Top Right: D. cleistantha, Bottom: D. imbricata 

Sect. Conchophyllum contains the shell leaved species which includes, Dischidia 

diphylla, D. cleisthantha, D. imbricata and many more. These plants have developed 

flat foliage that grows extremely close to the surface they are growing on. 

What’s interesting about this group is that not only do they provide nesting sites for 

arboreal ants like sect. Ascidiophora but the flat, sessile growth habit also creates 

the perfect environment for root development. Underneath each pair of leaves is 

dark, warm and moist. This also enables these species to withstand significant 

amounts of drought. 

6

Sect. Dischidia contains all the other species which have laminate or “normal” 

foliage. This also includes the genus Dischidiopsis which is a genus of questionable 

validity; more on that later. Even though the species of this section don't have special 

foliar apparatuses, many of them are still myrmecodial. Species like Dischidia 

rimicola can be found growing directly out of the arboreal ant nests of the genus 

Crematogaster. It has been observed that the ants harvest the seeds of these plants. 

This explains the association perfectly. The ants bring the seeds to their nest; the 

seeds germinate and then grow from it. 

Left: Dischidia litoralis Right: Dischidiopsis luzonica 

The genus Dischidiopsis contains a handful of species with Hoya-like foliage. The 

heaviest concentration occurs in the Philippine archipelago but are also found 

sparsely throughout SE Asia. One of the key features of the genus is that none of the 

flowers possess the anchor shaped coronal appendages that Dischidia do. Oddly, 

not all species have them either. The species of this genus have the same habitat, 

growth and general floral characteristics as Dischidia which is why its validity is in 

the air. I believe in the future, these plants will all be moved to Dischidia. 

Some Dischidia have medicinal uses as well. The foliage of the shell leaved species, 

Dischidia purpurea are crushed and cooked in coconut oil. This is then used 

as pomade for eczema and herpes. 

7

Flowers and Foliage 

Dischidia astephana 

The flowers of Dischidia may not be as; "flashy" as those of Hoya but that does not make 

them any less interesting. Many species have spectacularly colorful flowers while others 

have powerfully fragrant ones. Some have fairly large flowers like those of Dischidia diphylla 

(which also smell heavenly) while others are so minute one would almost require a 

hand lens to view them. 

Dischidia flowers (like all Asclepiads) are 5-merous, meaning that they have five petals 

(flowers of D. diphylla pictured). They exist in a variety of shapes from the urceolate flowers 

of Dischidia singularis to the campanulate flowers of Dischidia rhombifolia. Some may 

bloom for many days up to a week or so while others seemingly last only a single day or 

just slightly more. Many are born on long peduncles where they 

can be seen by pollinating insects like those of Dischidia purpurea. 

Some may bloom in groups or singly as in Dischidia hirsuta. 

Anthesis* isn't always apparent in many Dischidia. This is 

because there are many species that have flowers that appear 

closed. Those of Dischidia vidalii seem to appear closed constantly. 

Conversely, Dischidia griffithii has flowers that are widely 

divergent at anthesis, allowing full view of the gynostegium*. 

8

These flowers posses a few unique floral characters that set them apart from Hoya 

and the other genera of the family. Many of them contain hairs on the inside of the 

corolla. Some of them are quite visible by the naked eye as they cover the entrance 

to the corolla. Other species contain hairs further down the corolla tube only to be 

seen via dissection. Another neat feature of Dischidia flowers are the anchor shaped 

coronal appendages found in many species. These appendages are attached to the 

gynostegium. They can provide a means for identification as they are very differently 

sized and/or shaped between those species which have them. 

Undescribed species from Thailand 

Left: Dischidia lancifolia Right: Dischidia merrillii 

9

Pollination of the flowers is an area of grey in this genus. Not much research has 

been conducted on the specific vectors for pollinating them. In Rintz's account of 

the Malayan Dischidia (1980) he mentions 

that the likely pollinators of Dischidia 

would be lepidopterans (moths 

and butterflies). He continues to say that 

many believe ants would be vectors for 

pollination because so many Dischidia 

are associated with them, but any ant 

that would be small enough to fit inside 

the flower would be far too small to dislodge 

the pollinium* and then insert it 

just right into the grooves formed by the 

anther margins. I have personally witnessed 

moths, butterflies, ants, wasps, 

bees and flies all feeding on the nectar of Dischidia flowers. This doesn't necessarily 

mean that they are all vectors for pollination but at least gives some insight into 

where to start. Pictured here is a wasp drinking nectar from Dischidia bengalensis. 

The foliage of Dischidia exists in a wide range of shapes, sizes and vesture from 

the very large leaves of Dischidia acutifolia to the hairy foliage and stems of Dischidia 

hirsuta (hence the name). Some species are nearly impossible to distinguish 

from a Hoya when sterile because of their size, shape and thickness. Dischidia superba 

comes to mind. Its foliage is large, heavy, hard and dark green. Dischidia 

lancifolia, D. astephana 

and D. singularis are 

particularly notable for 

their foliage and represent 

but a small sample 

of the variability and 

beauty found in this 

genus of plants. 

10 

Dischidia acutifolia

Top Left: Dischidia hirsuta Top Right: Dischidia lancifolia Center: Dischidia singularis Bottom: Dischidia astephana 

11

Identification 

Clone of Dischidia acutifolia. Compare with picture on page 10 

Identification of Dischidia can be an arduous and stressful task. Like Hoya, there 

are many clones of the same species in existence some of which have different looking 

foliage but identical flowers. Furthermore, new species and/or varieties are discovered 

every year which can add to the mayhem as well as the fact that so many are 

incorrectly identified or not identified at all due to the lack of info available. 

Some important things to remember are that, like humans, there is variability in a 

single species. Some species contain clones with large glabrous foliage while other 

clones may be tiny and covered in dense hairs. Cultural influence can greatly change 

the look of foliage as well. Low light, lots of food and high humidity often will create 

large, dark green leaves while lots of light, little food and moisture will yield smaller, 

harder foliage. Temperature, light and nutrients can influence flower color and because 

of this it’s sometimes important to ignore flower color and instead pay attention 

to flower morphology. The age of the plant can also confuse as some species' vesture 

changes with age. For example, often times some species start out with dense hairs 

on young foliage and then slowly drop the hairs as those leaves gain age. Dischidia 

hirsuta and D. astephana are two examples of this occurrence. 

The best thing to do is to always label and keep records of your plants. Knowing the 

origins of what you have can be a powerful weapon in the battle for identification. 

12

Cultivation 

Epiphyte walls festooned in Dischidia 

As was mentioned earlier, Dischidia can be found in nature growing on the same 

tree as many Hoya species. This would lead to the idea that their cultural requirements 

are similar. If you've got a green thumb for Hoya, then you should have no 

problems growing most Dischidia. If your thumb is not so green, there are still some 

excellent species to grow and enjoy. 

Dischidia are found most commonly growing epiphytically in the rainforest edges 

along streams, roads, on exposed limestone hills and beaches. This tells us that Dischidia 

appreciate moisture, air flow and light. So when we grow them at home, we 

must attempt to provide those 3 basic things which is easy to do. 

Dischidia can be grown potted or mounted and do quite well either way. Growing 

these plants potted or in hanging baskets is the easiest and most common 

method as mounts can be difficult to maintain for those who live in arid regions. 

Potting mixes should drain very well but retain some moisture. A regular feeding 

schedule in the active growth months with any good orchid fertilizer will greatly 

benefit these plants. 

In this section of the article I will detail some cultivation tips and general info for 

a few easy, moderate and difficult to grow species. There is a Dischidia for everyone 

from the expert to the novice. It should be noted that my comments here are based 

on experiences growing these plants outside and in a greenhouse in central Florida. 

13

Easy Species 

Dischidia sp. Geri (hort) is an endemic to the Philippines. 

It has to be one of the most recognizable and/or common 

species available. This is no surprise as it is practically impossible 

to kill. The leaves are round and coin-like. The 

flowers are lantern shaped and white. The petals are held 

erect at anthesis. This species appreciates moisture and can 

handle being over watered better than any of them in my 

experience. It grows very well in indirect sun, damp not 

wet and well fed. 

Dischidiopsis luzonica Schltr. is one of the best beginner 

species to grow. This is because not only is it 

hardy and indestructible but it also blooms very 

early in age and seems to stay in bloom constantly. 

This species does the best potted in a well draining 

mix, fed sparingly and kept damp not wet. It loves 

to be root bound and will fill a pot with roots in no 

time flat. D. luzonica is endemic to the Philippines 

and it grows FAST! 

14 

Dischidia ruscifolia Decne. Ex Becc. 

(commonly called the, “Million 

Hearts Vine”) also hails from the 

Philippines. It is a shrubby species 

and doesn't twine so it is pretty 

much strictly a repelling grower. 

This species doesn't like too much 

root moisture and can handle quite 

a bit of sun. There is a tiny clone 

available that is also very fun to 

grow and has the same cultural requirements.

Moderate Species 

Dischidia truncata Decne. comes from the highlands of Java. It’s a smaller climbing/ 

twining species. The leaves have a beautiful broad lanceolate* shape. The flowers 

are born on approximately one inch peduncles 

in small groups of four or five and 

are long, tubular, white and have pink/ 

purple tips. Being that D. truncata is a 

highland species, it poses some cultural 

problems for those in warm climates but it 

is probably one of the more tolerant highland 

species. It does best for me kept 

shaded and damp but with decent air 

flow. It does equally well mounted or potted. 

Dischidia nummularia R. Br. is very common 

and widespread in SE Asia and can be found 

nearly everywhere. The flowers are most often 

born singly on sessile peduncles, are 

white and have a ring of hairs that conceals 

the entrance to the corolla. There are many 

clones of this species and all are slightly 

challenging to grow for those of us who are 

trigger happy with the water. This species 

does best left to dry out completely before being soaked again. D. nummularia is 

highly tolerant of high light levels and seems to be more prone to blooming when 

grown “high and dry”. 

Dischidia merrillii Schltr. is a beautiful trailing species 

from the Philippines. The leaves are lanceolate, 

smooth, thin and oddly hard. The flowers are 

a livid purple and tubular in shape. Its closest 

relatives are D. lancifolia and D. hirsuta. D. merrillii 

can be a little challenging because it really 

needs very high humidity and this can be difficult 

for those in the drier areas. It also appreciates 

some root moisture, bright indirect sun and food. 

It will reward with multiple flower filled peduncles 

if these needs are met. 

15

Difficult Species 

Dischidia scortechinii King & Gamble is a 

highland species from peninsular Malaysia. 

The foliage is lanceolate, has palmate venation 

and is rather thin and fragile. The flowers 

are white, tubular, have reflexed lobes 

and are born on short peduncles in groups 

of 4 or 5. This species is very sensitive to 

light and heat. D. scortechinii prefers bright 

shade, lots of humidity and temps no higher 

than 80 degrees F (27 degrees C). If you live 

somewhere very warm, its best to keep this plant constantly misted and in a shady 

area with decent airflow but take care not to over water the soil mix. 

Dischidia astephana Scort. ex King & Gamble is a 

shell leaved species found in the mountain 

forests of peninsular Malaysia and Borneo. 

The foliage is notable for the small bumps 

and dense hairs. The flowers are red and blue 

and shaped like an onion. D. astephana (like 

many shell leaved species) seems to do best 

mounted but can be grown potted. It likes 

high light, moisture and cool temps. The foliage 

will blush a beautiful red in intense light. 

Be careful with feeding as too much will create flimsy weak foliage that seems to 

have more problems with rot. 

Dischidia dolichantha Schltr. is a wiry vine, highland 

species from peninsular Malaysia, Sumatra and Borneo. 

Its foliage is very similar to D. scortechinii but 

much smaller and slightly narrower. The flowers are 

very long, tubular and white with reflexed lobes. D. 

dolichantha is also culturally similar to D. scortechinii 

but seems to be slightly more forgiving with 

temps. This species seems to do much better potted 

vs. mounted because the thin stems rot when surrounded 

by damp moss. 

16

I hope you have found this article enjoyable and most importantly informational. 

These plants are beautiful and fun to grow and as such, deserve the attention of 

anyone who enjoys growing Hoya or any plant. The various species can be fun to 

display and always attract attention when visitors arrive. So hop on the internet or 

go to your local garden center and try a species or two. You won’t regret it! Happy 

growing! 

-Antone 

n 

17

Photography 

Photos and text by Ed Gilding 

(Editor’s note- This continuing feature in Stemma will focus on non-traditional photography 

and subjects as well as the beautiful floral photography created by many Hoya 

growers and collectors. The microphotographs featured in this issue were captured by Ed 

Gilding using a scanning electron microscope. These are 60x to 200x magnification images 

of the inner corollas of flowers of Hoya carnosa R. Br.) 

18

The tall banana-like appendages appear (we would need to stain 

fixed tissue with a dye that lights up the nuclei to confirm this) to be 

single cells called trichomes, which are modified epidermal cells. 

19

What is interesting is that it seems the trichomes form in small elongated 

bunches and appear to be very smooth (waxy exudates?*) so 

that they form scales, as seen with the naked eye. n 

_________________________________________________ 

20

Reprint: Hoya Pottsii Traill from Curtis’ Botanical Magazine, 1835 

21 

(Editor’s note- This is the first 

in a series of reprints of important 

publications of Hoya 

or Dischidia species from past 

botanical magazines and 

journals. This material is often 

available only in certain botanical 

libraries or herbariums, 

often in locations inaccessible 

to many researchers 

or hobbyists. The digitalization 

of these entries and their 

correspondingly wider accessibility 

is an important and 

exciting advance and is being 

enacted by many sources- the 

two most notable being the 

Google Book Search project 

(www.books.google.com) and 

the Missouri Botanical Garden 

(www.botanicus.org). 

Google is working to digitalize 

and make searchable and 

viewable in their entirety an 

extraordinary number of noncopyrighted 

older texts, as 

well as excerpts of copyrighted 

works, and The Missouri 

Botanical Garden provides 

free and complete access 

to over 250 rare texts 

from the 18th and 19th centuries.)

( 3425 ) 

HOYA POTTSII. MR. POTTS’S HOYA 

******************** 

Class and Order. 

PENTANDRIA DIGYNIA. 

( Nat. Ord. ---ASCLEPIADEAE. ) 

Generic Character. 

Massae pollinus laeves, 10, erecto-conniventes. Antherae membrana terminatae. Corona 

staminea pentaphylla, foliolus depressis, angulo interiore producto in dentem 

antherae incumbenetem. Cor. rotata. Br. 

Specific Character and synonyms. 

HOYA* Pottsii; follis cordato-ovatis brevi-acuminatis supra trinerviis, corolla supra 

vix pubescente. 

HOYA Pottsii. Traill, in Hort Trans. v. 7. p. 25. t. 1.?, Loddiges, Bot. Cab. t. 1609*. 

Cultivated in the stove of the Bot. Garden of Glasgow, where it flowers in May. it 

is much to be regretted that MR. TRAILL, in his otherwise valuable paper on the 

different species of HOYA, has not more precisely defined the characters between 

his HOYA Pottsii and H. trinervis. Our plant is undoubtedly the H. Pottsii of the 

Bot. Cabinet, but the colour of the flowers is different from that of Mr. TRAILL, 

and in this respect, as well as in some others, it agrees better with the trinervis, of 

which its author says, “It bears a great resemblance to H. Pottsii, from which, however, 

it may be principally distinguished by its larger and thinner leaves, the veins 

of which are more strongly marked, and also by the yellowish colour in the centre 

of the crown.” May not the two varieties be one and the same plant? in ours, the 

22

old leaves at the base of the plant are much thicker than the upper ones, and have 

the nerves more obsolete. From H. carnosa the species is best known by its larger, 

broader, three-nerved leaves, and the almost entire absence of down upon the upper 

surface of the corolla. It wholly wants the bright red spots in the inside of the 

crown and the rich smell certainly cannot be compared to that of a “rich plumcake, 

or a combination of that of honey with the almond flavour of the Peruvian 

heliotrope,” (to which that of H. carnosa is likened by Sir J. E. SMITH,) but rather 

resembles that of strong and bad honey. 

If we are correct in considering the plant to be the original H. Pottsii, it is a native 

of the vicinity of Macao, where a leaf was gathered by a zealous collector to the 

Horticultural Society, whose name it bears, and which, being given to Mr. SABINE, 

and planted, soon flourished. The H. trinervis was brought from China by Mr. 

JOHN DAMPER PARKS. 

DESCR. Stem long, branched, twining, the extremities frequently leafless and 

rooting. Leaves ovato-cordate with a short acumen; when old, very thick, and between 

fleshy and coriaceous, convex below, and pale-green, with scarcely an appearance 

of nerves; above concave, deep-green, with one central and two lateral 

nerves, the middle one sometimes sending out very obscure lateral oblique ones, 

the margin slightly revolute. Petioles rounded, short, very thick; when old, clothed 

with a sort of pale-brown bark. Peduncle from the side of one of the petioles at its 

base, two inches long, bearing a compact almost globose umbel of flowers. Calyx 

with five short, broadly ovate teeth. Corolla rotate, of five broadly ovate, acute, 

very pale yellow-green lobes, quite glabrous below, above so slightly downy that 

the pubescence can only be seen by the assistance of a microscope. Crown of five 

large, depressed, fleshy, ovate, spreading, white leaves, between which the color is 

orange. 

* Named in honour of Mr. THOMAS HOY, gardener to His Grace the Duke of 

Northumberland. 

* The last citation should read “Loddiges, Bot. Cab. t. 1969”. 

___________________________________________ 

23

Hoya Pottsii Traill 

by Mark Randal 

Lectotype illustration of Hoya pottsii from Transactions of the 

Horticultural Society, James Traill, 1830. 

24 

The species Hoya pottsii trail 

has a complex publication 

history and an uncertain relationship 

to the collections 

now in cultivation believed to 

represent this species. The 

type illustration for this plant 

(left), which appeared in 

18301, depicts a plant with 

trinerved* leaves with acuminate* 

tips. The flowers here 

have pale, reflexed corollas* 

and concave-topped white coronas* 

with raised apexes and 

red markings on the inner corona. 

The stems appear rather 

thick as do the leaves, judging 

by the depicted leaf edges. 

The original type description 

for this species cites the collection 

locale as Macao, a district 

in extreme south-eastern 

coastal China, and the collector 

as John Potts, for whom it 

was named. 

Since its original description, 

subsequent publications 

have placed Hoya pottsii into 

synonymy under other species 

names2, or conversely 

have placed other species 

into synonymy under Hoya 

pottsii3. The distribution has 

been defined variously as localized 

to southern China4 or 

occurring primarily in Australia 

and New Guinea3.

In cultivation many Hoya with diverse floral and leaf morphology have received the 

label “Hoya pottsii”, some appearing to be very similar to the type illustration with its 

trinerved leaves and some being very different, having pinnate*, triplinerved* or quintuplinerved* 

leaves and differing floral characteristics. 

Some botanists question whether any of the plants in cultivation match the type sheet 

of this species well enough to be labeled Hoya pottsii5. 

Key publications of Hoya pottsii Traill 

Hoya pottsii was first described in Transactions 

of the Horticultural Society 7 

(1830) by James Traill. The material described 

here was cited as having been collected 

in the vicinity of Macao (SE China), 

although this claim has been questioned in 

later works3. Hoya pottsii was featured in a 

number of works through the 1830s and 

‘40s, but little was added to the description 

in these publications, the text in these instances 

often being excerpted from the 

original publication. Two exceptions are 

the illustration that appeared in The Botanical 

Cabinet6 in 1833 and the illustration 

and description appearing in Curtis’ 

Botanical Magazine in 18357 (this article is 

reproduced in its entirety in the Reprint section 

of this issue of Stemma). Around this 

time several articles appeared which supported 

the collection of this species from 

southern China4,8. 

This species received a major revision in 

the 1992 article “Taxonomic Studies on the 

Genus Hoya R. Brown in Papuasia” by Forster 

& Liddle3 which appeared in the Australian 

botanical journal Austrobaileya. Here the 

authors defined the distribution for this 

species as “Celebes, New Guinea and Australia”, 

and placed the species Hoya 

nicholsoniae F. Muell., Hoya hellwigiana Warb. 

and Hoya sogorensis S. Moore into synonymy 

with Hoya pottsii. They also designated the 

plate which accompanied the original publication 

of Hoya pottsii in Transactions of 

the Horticultural Society 7 as the lectotype* 

for this species. 

25 

Illustration of H. pottsii from The Botanical Cabinet, 1833. 

This image is Photoshop reconstructed from a very poor 

photograph, the only image available to Stemma, 

so is not an exact reproduction.

In Blumea 40 (1995)2 a treatment of Hoya verticillata G. Don places Hoya pottsii and approximately 

a dozen other names as synonyms* to Hoya verticillata. This work is based 

on the premise that Sperlingia verticillata (Sperlingia was a genus description written for 

the genus Hoya at about the same time, but beaten to publication by the genus description 

“Hoya”), one of two species described for that genus, was synonymous with a broad 

combined taxon* of species which included H. pottsii and H. acuta Haw. (a species collected 

originally from eastern India with flowers similar to H. pottsii, but leaves bearing 

pinnate* venation- see image page 32). The placing of H. pottsii as a synonym to Hoya 

verticillata does not seem to have been accepted by most botanists5,9,10, and does not often 

appear in this form in subsequent literature. 

In 1995-96 The Hoyan12 printed a series of articles attempting a tentative revision of the 

sectional divisions (where groups of species are put together based on similar physical 

characteristics) of the genus Hoya. There Christine M. Burton created a new sectional division, 

section Hoya subsection lactisuccus C. M. Burton, which had Hoya pottsii as its representative 

species. 

The description for this subsection reads, in part, “foliage fleshy; sap milky; corolla 

lobes flat or reflexed; corona lobes more or less flat on top but often elevated at the outer 

tips”. Other species placed in this section at the time were Hoya aldrichii Hemsl., hoya 

bhutanica Grierson & D. G. Long, Hoya hellwigiana, Hoya nicholsoniae (these first four listed as 

synonyms for pottsii), Hoya benquetensis Schltr., Hoya bordenii Schltr., Hoya incrassata 

Warb., Hoya finlaysonii Wight, Hoya glabra Schltr., Hoya merillii Schltr. and several others. 

Given that this study was published over 10 years ago, and was not intended to be an exhaustive 

placing of species known at the time, there are a great many more species that 

now would likely be placed here as well, such as Hoya acuta, Hoya macrophylla Blume, 

Hoya pachyclada Kerr, Hoya wibergiae D. Kloppenburg and many others. Even considering 

only the originally placed species, this subsection contains species which cover very 

nearly the entire range of the genus distribution for Hoya (see map page 27) and probably 

constitutes the largest group of morphologically similar Hoya species. 

While this study was a preliminary attempt to revise the sections and despite sectional 

theory having fallen somewhat into disfavor following Burton’s work and a revision by 

Dale Kloppenburg13 a few years previous to the Burton study, this new grouping remains 

significant as it is the first time that these species, so similar in floral character, were officially 

recognized as a distinct taxon inside the genus Hoya. 

In Thailand, most botanists currently seem to view Hoya pottsii and Hoya acuta as parts 

of a single variable taxon which they deem the “Hoya parasitica (Roxb) Wall. ex Traill complex”11. 

While the view of these two species as part of a wide, variable taxon (as in the 

Blumea article) may certainly be argued, the name Hoya parasitica is not a valid name for 

this complex or for any single species. A version of the name Hoya parasitica first appeared 

in 1814 as Asclepias parasitica in a catalog of plants of the East India Company’s 

Botanical Garden at Calcutta14. This name appeared there only as a catalog entry, with no 

description. The name Hoya parasitica did not appear until 182415, after the 1821 publication 

of the name Hoya acuta, which name Hoya parasitica was placed under synonymy 

to in 189816. 

26

A map detailing the collection sites of some of the Hoya in subsection lactisuccus. The red border defines the 

distribution of the genus Hoya, based on historical and modern collections and citations. Collections of H. pottsii 

are in blue, H. nicholsoniae are in green, and the pink numbers are similar species thought to be closely related 

to both. (1)- Chiang Mai, Thailand, source of the pottsii collection depicted on pages 29 and 30. (2)- Macao, 

China, cited as the original collection vicinity of H. pottsii. (3)- H. nicholsoniae. (4)- H. pottsii IML1449. 

(5)- H. pottsii IML1193. (6)- H. pottsii IML1395 (7)- H. acuta. (8)- H. bhutanica. (9)- Hoya rigida . (10)- H. 

cominsii. (11)- H. hellwigiana. (12)- H. samoensis. (13)- H. neocalidonica. (14)- H. neoebudica. (15)- H. merillii. 

(16). H. finlaysonii. 

Identity of Hoya pottsii in distribution and cultivation 

In determining which populations in nature or collections in cultivation best match the 

type material and description of Hoya pottsii, it is necessary first to take a moment to discuss 

the determination of the plant present in cultivation as Hoya sp. from Chiang Mai. 

This thick leaved, semi-succulent plant has been determined, by various authorities, to 

represent either the species Hoya subquintuplinervis Miq. or the species Hoya pottsii. In 

considering this determination it is necessary to consider one more plant, a truly succulent, 

round leaved plant which has also been sold as Hoya pachyclada GNT (Green Nontypical 

Form) and Hoya IML 1701. The botanists who consider Hoya sp. from Chiang Mai 

to be a collection of Hoya pottsii consider this plant (H. pachyclada GNT, IML1701) to be 

the true Hoya subquintuplinervis. 

27

Here is a photo montage of (from left) a typical leaf from Hoya IML1701, a detail from 

herbarium sheet Teysmann #6037 labeled as a lectotype* for Hoya subquintuplinervis, 

and a typical leaf from Hoya sp. from Chiang Mai. 

When comparing these images please note that the lectotype detail shows a rounded 

leaf with several prominent veins branching off from the midvein ABOVE the leaf base. 

This form of branching is called triplinerved (with three main veins) or quintuplinerved 

(with five main veins). This compares very favorably with the leaf shape and venation of 

the leaf from IML 1701. The stem of the lectotype material is also extremely thick, which 

compares favorably with IML 1701 (see the entire lectotype sheet in Appendix A). 

The representative leaf from Hoya sp. from Chiang Mai is, by contrast, ovate (eggshaped) 

with a more pronounced acuminate* tip and is prominently trinerved (three main 

veins, all arising from the same point at the leaf base). The resemblance of the leaves, 

stems and peduncles of the lectotype material to that of IML 1701 are blatant and would 

seem to preclude the determination of Hoya sp. from Chiang Mai as Hoya subquintuplinervis. 

So what is Hoya sp. from Chiang Mai? 

28

A comparison using a photograph of (left) a wellgrown 

flowering specimen of Hoya sp. from Chiang 

Mai (pottsii) and (right) the lectotype illustration 

for Hoya pottsii. Photograph by Roy Bilbie of 

Brisbane, QLD, Australia. 

Let’s compare Hoya sp. from Chiang Mai with the lectotype of Hoya pottsii. Note that 

the leaves of each are ovate with an acute* tip. In each there are three prominent veins 

that arise at the same point at the leaf base. The flowers of each are pale, with reflexed 

corollas and coronas which are broad in the middle, acute at either end and have a 

slightly concave flat top with the corona lobe apexes slightly higher than the center. 

There are also some slight differences. The leaf bases of Hoya sp. from Chiang Mai are 

slightly rounded, while those of the pottsii lectotype are more acute. The underside of the 

leaves depicted in the pottsii lectotype are of a lighter color than the tops, while those of 

Hoya sp. from Chiang Mai are uniform in color on both surfaces, except where exposed 

to direct sun. The inner tip of each corona lobe of the pottsii lectotype is colored a deep 

red, giving each corona a distinct red central spot while those of Hoya sp. from Chiang 

Mai have a yellowish coloration in the central corona. 

29

Comparison of flower clusters of (left) closeup of H. pottsii lectotype and 

(right) photo of H. sp. from Chiang Mai (pottsii) by Roy Bilbie of Brisbane, QLD, Australia. 

The leaf base shape of the type illustration is depicted as slightly acute, but the written 

description cites the leaf base as being “cordate”, which matches well to Hoya sp. from 

Chiang Mai. While the type illustration has priority over the written description, both the 

written description and this painting were made from the same single clone of this species 

in cultivation at the time (see reprint), so this factor would not seem to be concrete, 

and can be (as are the color of the underside of the leaves and the coloration of the inner 

corona) considered variable minor traits within a species17. Stronger floral and leaf variation 

than this may be seen in the differing colors of flowers in various clones of Hoya 

archboldiana C. Norman and Hoya imperialis Lindl. and in the varying leaf size and shape 

within the species Hoya australis R. Br. ex J. Traill. 

So the Hoya sp. from Chiang Mai seems to be properly determined as Hoya pottsii from 

Chiang Mai. 

Chiang Mai is a region of northern Thailand approximately 1500km (just over 900 

miles) southwest of the Macao region of southern China which is cited as the original collection 

area for Hoya pottsii. 

There are several other collections of Hoya pottsii from this general region (Thailand, 

Malaysia and Vietnam) which match well with the pottsii type: H. pottsii IML 1395, from 

the Cameron Highlands, Malaysia and H. pottsii IML 1449 from southern Thailand both 

display the colorful leaves and red centered corona which is illustrated in the lectotype. 

H. pottsii IML1193 from Vietnam, with green tinted corollas and magenta centered coronas, 

also represents this species, although no collections from China itself seem to be 

identified in cultivation so far. 

30

Above left: Hoya pottsii IML1395 from Malaysia. 

(photo of IML1395 courtesy of David Liddle.) 

Above right: Hoya pottsii IML1193 from Vietnam. 

Now let’s look at the Hoya native to Australia 

and New Guinea that have been 

placed into synonymy with pottsii. 

These collections were determined to be 

Hoya nicholsoniae18 before they were 

placed in synonymy under Hoya pottsii by 

Forster and Liddle3. To the right is a montage 

of David Liddle’s illustration of H. 

nicholsoniae showing triplinerved* or 

quintuplinerved* leaves and two collections 

of nicholsoniae with matching venation. 

This vein pattern does not match well 

to the type illustration of H. pottsii. 

The floral characteristics of the Hoya 

nicholsoniae collections to date are rather 

varied. Some have highly rhombic* corona 

segments with a distinctively flat-looking 

top, and a rather compact arrangement 

compared to the coronas of pottsii from 

Thailand and Vietnam. 

31 

i

Other collections have corona 

segments which are 

extremely similar in shape 

and placement to those of 

the northern pottsii species 

(as well as to those of Hoya 

acuta- see photo comparison 

to the left). One collection, 

IML0039, has corona 

segments with rounded 

apexes. All of these collections 

have triplinerved 

veins, however, which distinguishes 

this group from 

the northern population of 

Hoya pottsii. 

Are H. pottsii and H. 

nicholsoniae similar enough 

plants to be defined as the 

same species? A case may 

be made either way, and it 

seems that genetic testing 

may be a way to resolve 

this question. However, if 

the nature of a species were 

to be defined so broadly 

(accepting a variety of venation 

and corolla and corona 

detail as seen in the range 

of these two populations) it seems there are many other Hoya species with similar minor 

differences in morphology which would also have to be placed into synonymy with pottsii, 

including (but not limited to) Hoya acuta, Hoya bhutanica, Hoya hellwigiana and 

south Pacific islands species similar to Hoya cominsii and Hoya samoensis, probably under 

the name Hoya verticillata G. Don , the first species believed to belong to this group to 

be described, as outlined in the 1995 Blumea paper. This kind of lumping, applied over 

the whole genus, would lead to radically fewer species names with a great deal of variation 

in each, and would probably result (due to labeling limitations) in the obscuration of 

the geographic origin of many plants in cultivation. Since this does not seem to be a desirable 

state of affairs, and since the attempt to move in this direction by the 1995 Blumea 

paper has lost seemingly all traction, it seems proper that these Australian and New 

Guinean species determined as Hoya nicholsoniae and then as pottsii should remain as 

Hoya nicholsoniae. n 

_______________________________________________ 

32

Department of corrections 

In the last issue of Stemma (V.1,#4), In the article “Propagating Dischida” on page 18, 

the photo labeled as “Dischidia cornuta aff.” should be labeled as “Dischidia milnei”. 

Also in the last issue of Stemma in the Department of Corrections, the subject of the 

correct plural form and capitalization of Hoya was discussed. Stemma there adopted the 

position that in its pages the plural would be written as Hoya instead of Hoyas, and 

would always be capitalized. Christine M. Burton wrote in with this comment: 

“I think the spelling of Hoya depends on how it is used and which language. In Latin, I 

believe (based on other words with the same ending) that Hoya is plural and singular 

would be Hoyum. However, I have never seen it spelled that way so I'm probably wrong. 

If writing in English, I believe that Hoya is singular and Hoyas is plural. 

I know that when writing Hoya and referring to the genus that the genus name is uppercased 

but if referring to hoyas in general that the lower case is correct.” 

Other sources Stemma consulted had varying takes on this question, and so it seems 

that this point may be debatable, and is certainly complex. Stemma’s Latin is somewhat 

poorer than “rusty”, but we will continue to look into the matter. For the time being, and 

for consistencies sake, Stemma will maintain the capitalized genus name in all instances 

and “Hoya” as the plural form, though this admittedly does seem somewhat awkward at 

first. However, for contributed material Stemma will now leave the precise usage up to 

the contributing individual. 

Source Materials: 

for Hoya Pottsii: (1)- James Traill. 1830. Transactions of the Horticultural Society 7. 

pg.25. (2)- Veldkamp, J.F., R. van Donkelaar & R.D. Kloppenburg. 1995. Blumea 40. 

“Synonym of Hoya; H. verticillata correct for H. parasitica” . pgs. 425-428. (3)- P. I. Forster 

& D. J. Liddle. 1992. “Taxonomic Studies on the Genus Hoya in Papuasia”. Austrobaileya 

3/4 pgs. 627-641. (4)- Tsiang. 1936. Sunyatsenia 3. pg. 171. (5)- R.D. Kloppenburg. 

2001. The Passport Hoya Series. (6)- Loddiges. 1833. The Botanical Cabinet. t. 

1969. (7)- 1835. Curtis’ Botanical Magazine. t. 3425. (8)- J. Tsiang & P. T. Li. 1974. Acta 

Phytotaxinomica 12/1. pgs. 124-125. (9)- Burton, Christine M. 2001. The Hoyan. V.23,#1. 

pgs. 6-11. (10)- Burton, Christine M. 2005. P. S. The Hoyan. V.3, #4. (11)- Manit Kidyue 

et. al. 2006. “Variation within the Hoya parasitica (Asclepiadaceae) Complex in Thailand”. 

(12)- Burton, Christine M. 1995-96. The Hoyan. V.17 #2 part2:10-12, #3 part 

2:14-18, V.18 #1 part2:3-6, #2 part2:9-13. (13)- R. D. Kloppenburg. 1994. Hoya Sections: 

a complete study with Modifications and Additions. (14)- William Roxburgh. 1814. Hortus 

Bengalis. (15)- William Roxburgh & Nathaniel Wallich. 1824. Flora Indica. pg. 36. 

(16)- James Britton.1898. Journal of Botany British and Foreign 36. pg. 418. (17)- Shai 

Meriri & Georgina M. Mace. 2007. “New Taxonomy and the Origin of Species”. PLOS 

Biology. (18)- P. I. Forster & D. J. Liddle. 1988. Hoya in Australia. pg.17 

33

Glossary 

Acute- the shape of the apex (tip) or base of a leaf, petal or corona where the tip 

tapers to a sharp point. 

Acuminate- the shape of the apex (tip) or base of a leaf, petal or corona segment where 

the tip tapers to a sharp point in a concave manner. 

Anthesis- the period during which a flower is open. 

Cordate- heart-shaped, with the point upward and an emarginate base. 

Corolla- the collective unit of all the petals of a flower. 

Corona- (Latin for “crown”) the whorl of structures between the corolla and stamens. In 

asclepiads (Hoya, Stapelia, Ceropegia, etc.) comprised of five lobes or “scales”. 

Corona scale apex- the outer tip of each corona lobe, away from the center of the flower. 

Exudate- material that oozes out of a plant including gum, sap, resin, and latex. 

Gynostegium- A structure formed from the fusion of the anthers with the stigmatic region 

of the gynoecium. 

Lanceolate- Much longer than wide, broadest below the middle and tapering to the apex. 

Lectotype- a representative (herbarium specimen or botanical illustration) chosen as the 

standard bearer of a species or subspecies. 

Nerves- the conspicuous, mostly unbranched main veins of a leaf. 

Pollinia- a pair of coherent masses of pollen grains. Singular: pollinium. 

Pinnate venation- a pattern of veins with many side veins branching from a conspicuous, 

single main vein, resembling the structure of a feather. 

Quinquinerved- having five main veins, all branching from the same point of the leaf 

base at the juncture with the pedicel. 

Quintuplinerved- having five main veins- a midvein and two sets of other main veins 

branching from the midvein ABOVE the leaf base. 

Rhombic- diamond shaped. 

Synonymy- a section of a systematic presentation about an organism that lists all of the 

names that have been used for the organism, some of which may have been previ 

ously thought to represent different organisms. A combining of names under one 

more correct name. 

Taxon- a group of similar organisms of any taxonomic rank. 

Trinerved- a vein pattern with three main veins branching from the same point of the 

leaf base at the juncture with the pedicel. 

Triplinerved- a vein pattern with three main veins- a midvein and two other prominent 

veins branching from the midvein ABOVE the leaf base, 

Vesture- something that covers, like a garment. Also: a reference to general appearance. 

34

Appendix A: lectotype for Hoya subquintuplinervis Miq. (Teysmann #6037) 

35

Appendix B: illustration of Hoya griffithii Hook. f. 

from Curtis’ Botanical Magazine, 1866. t. 6877 

36

Back Page: Hoya griffithii Hook. f. 

text and photographs by Torill Nyhuus 

(illustrated page 38 & Appendix B) 

Country of Origin: This noble species of Hoya was discovered by the botanist and collector, 

Dr. W. Griffith, in the Khasia Mountains of Eastern Bengal, between Assam and Silhet, 

and afterwards collected there by Sir Joseph Hooker. Elevation 2000 - 4000 feet. Also recently 

seen on Hainan in China with pale pink flowers. 

Related/Similar Species: Based on floral characters H. griffithii seems to be related to 

Hoya imperialis Lindley. The flowers are visually similar to Eriostemma coronaria (Blume) Kloppenburg, 

though those two plants are not closely related. 

Flower Colour: Cream white to pale pink. Has small pink spots at the back of the corolla 

lobes. 

Flower Size: About 1! inch (3.75cm) in diameter. 

Flower Form: Rotate. 

Scent: Yes, nice. 

Leaf size: Oblong leaves 3 ! - 6 inches (8 - 15cm) long, " - 1# inch (2 - 3cm) broad, 

narrowed to an acuminate apex and an acute base, glabrous. 

Temperature Range: The elevation where it was found tells us it would like a temperature 

of 20 – 25 ° C (68 - 77 ° F) 

Water Requirements: I got my cutting 2005. In spring 2007 I repotted my plant in a self 

watering pot where it grows better and bloomed in November with three umbels. 

Light Requirements: Bloomed here under artificial light . 

Cultivation Notes: This plant isn’t difficult to grow, but a slow grower. A problem is that it 

aborts the buds most of the time. 

This species is a climber/twiner and needs a support to climb on. 

37

HOYA Pottsii - Cubits

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?