Vol. 4, #4

October 1, 2005



Hoya carnosa R. Br. Photo by George Slusser (Permission to use here granted)


          I am writing this and posting it here at the request of a member of the HoyasRUs MSN Forum. Before I start I want to make one thing perfectly clear.  This is the very last time that I will write another word about Hoya carnosa.   I am sick and fed up with the subject. If anyone else asks my answer will be, “WHO CARES?!!!!!!!”


Now, here it is, the Dick and Jane / Baby Ray primer of Hoya carnosa!


          Once upon a time, there was a man named Linnaeus.  He was a Swede. Linnaeus had a son. I presume he was called “Junior.” Junior published a new species of plants. He called that species, Asclepias carnosa. He did that in the year 1781. In 1805, J. Sims, published a picture of it in Curtis Botanical Magazine  (t. 788). It has broadly ovate leaves and looks exactly like the hoya that we know today as Hoya motoskei. 

          Robert Brown took one look at  Junior’s Asclepias carnosa  and knew it wasn’t an Asclepias so, in 1810, he published  that sucker as Hoya carnosa. Not knowing that Robert Brown had beat him to the draw (just barely), a fellow named Jacquin published the same species again in 1811, as Schollia crassifolia. 

          By 1819, a chap named Haworth, recognized Schollia crassifolia as a hoya, but did not recognize it as Hoya carnosa, which I find very strange because there were so few hoyas around in those days that it seems to me he ought to have been able to keep track of all of them, especially since Jacquin illustrated his publication of Schollia crassifolia in such detail. Haworth republished it as Hoya crassifolia (Jacq.)

Haw. You’ll find Jacquin’s illustrated publication in  Eclogae Plantarum Rariorum  vol.6, p. 50, published in 1811. The illustration measures about 2 X 3 feet and features sketches of all the individual flower parts.

      It wasn’t until 1855 that  Johannes Elias Teijsmann and Simon Binnendijk got around to naming and publishing this same species as Hoya motoskei in Nederl. Kruidk Archif.  (Don’t ask what those abbreviations mean – I’ve never been able to learn). In the same year, in Tuinbouw Flora  they gave us more detail and published a picture of it. The picture spanned two full pages.  There is no doubt that it is the same hoya as the one in Botanical Magazine and in Eclogae Plantarum Rariorum.

                I don’t know when we in the US started calling this one Hoya motoskei.  Up until about 1975, every example of it that I encountered was mislabeled Hoya australis.  As recently as 1980 there were mail order nurseries in Texas (Loyce Andrews) and Ohio (Esterbrook) who sold it mislabeled as Hoya australis (while selling Hoya australis  as dozens of other species but never as Hoya australis).

                Dr. Wim Baas and his associates at the University of Utrecht in the Netherlands studied the chemical properties of hoyas back in the  late 1970s and  early 1980s.  They determined that the hoyas given to them as Hoya carnosa  and Hoya motoskei differed.  The conclusion made by many of us was that meant that Hoya motoskei  was one species and Hoya carnosa was another species. Dr. Baas said that he and his fellow researchers made no attempt to confirm the correct identify any of the hoya species they studied.  They used the names that people like you and me gave them. They assumed the names to be correct.  Some of them weren’t. What this research  actually proved was that the two hoyas used in Dr. Baas’ study were not the same species.


Hoya motoskei cannot be different from Hoya carnosa  because it is Hoya carnosa.


                What are the ones with smaller leaves that all of us think is Hoya carnosa? I am sure that some are also Hoya carnosa,  --- just different collections of it found in different places. Just as you find many leaf sizes and shapes in such species as Hoya pottsii  and Hoya australis, so you’ll find them in Hoya carnosa.

                Some of those  we grow as Hoya carnosa are  selfed seedlings of  Hoya carnosa  or hybrids of it with whatever some hybridizer had growing near by it. The old Loyce Andrews catalogs dating from the 1960s and 1970s listed at least 40 so called “hybrids” of Hoya carnosa, none of which looked different. Some were given names and some had only numbers. 

          The late Genevieve McDonald sold thousands of seeds in the Florida Market Bulletin.  All of those “Ones” came from her (Sweet One, Pretty One, Little One, Cream One,  Bright One, etc.  and also Red Buttons and Gold Star). She did not hybridize.  She just collected seed from the plants that grew in her Merritt’s Island garden.  She had no idea if the seeds were from self pollinated flowers or were crosses.  I know this  is true because she told me so. She named many of the  pink flowered  seedlings  and many of us still grow them.  Some of us grow them with wrong labels attached.  Many more of us likely grow them with no labels attached because there are thousands (maybe millions) of people who remove labels and throw them away as soon as they get their plants.  They think labels distract from the beauty of their decorating schemes.  Many share cuttings with people who want to know what they have.  These people ask other growers and are frequently told,  That is Hoya carnosa” or  “That is Hoya motoskei.”   I’m sure that there are still people out there that think it is Hoya australis.

                Hoya carnosa has more cultivars than the Milky Way has stars and 99% of those cultivars have never been registered.  Most of those that have been registered or just given names, don’t look one iota different than most of the others

                What about Hoya fungii? I haven’t seen a holotype but I have examined an isotype specimen of it.  An isotype specimen is one taken from the same plant as the holotype and at the same time.  The isotype has leaves of about the same size and shape as those of Hoya pubicalyx cv. Pink Silver.  This isotype’s leaves were glabrous on both sides. I’ve also examined several species cited by the author of

Hoya fungii as being the same species (paratypes).  These have leaves that  are almost round and they have hairs on the undersides.  I compared flowers of both and  they appeared identical to me.  Although, shorter in length in ratio to width, the corona lobes, in profile, look very like those of Hoya pubicalyx.  The greatest difference I found in this one is the size of the peduncles.  Some were very short but most were about 4 – 4.5 inches long and so slender they were like thread.  When mine bloomed the umbels had about 50 flowers.  I marveled that such  slender peduncles could support the weight of so many flowers.

          It might surprise you also to know that the so-called Hoya carnosa  cv. Snowball’s corona is just about identical to that of Hoya pubicalyx  cv. Pink Silver, except for being larger.

          I do not know when or how the smaller leafed hoya that we call Hoya carnosa first got into our collections.  I have often guessed that it might have been brought over here in colonial times but I have no evidence of that.  It is possible that it didn’t get here until around 1904.  There was a hoya listed in a USDA Inventory from approximately that time.  If my memory serves me it was USDA 24475 (or a number very close to it).  The way I learned about it is that a hoya friend inherited a plant from her mother, who inherited it from her grandmother.  Those ladies were very careful and preserved the label through all those years.  I was given a cutting and a picture of it around 1980.  It appeared to me to be the one we call Hoya carnosa, though the USDA had not labeled it that with certainty.

           I read somewhere recently that it was easy to tell the difference between Hoya carnosa  and Hoya motoskei by  leaf shape and the speckling on the leaves of Hoya carnosa.  The writer said that “Hoya motoskei leaves have no speckling at all”. Such rot!

          Another myth I read about Hoya motoskei was found in a Hoya dictionary, written by a man who can’t spell and who doesn’t know the meanings of very many words.  He said that Hoya motoskei was named for a town in Japan.  One of the authors’ of the name (Teijsmann) wrote that it was named for a physician that he consulted when in Japan, a Dr. Motoske.  He said that he obtained cuttings of the plant from Dr. Motoske, who had treated him. It was in Japan that the synonymous name for this species,  Hoya rotundifolia, originated.

                If Hoya carnosa were not an extremely variable species, Genevieve McDonald would not have been able to select so many different cultivars of it from among its seedlings.  One of those she named “Little Leaf.”  It’s leaves are only about 1.5 inches long X @ 1 inch wide.  Another she named “Little One.”  That turned out to be a misnomer because the leaves, though small at first, grew to be even larger than most of those called Hoya motoskei.  “Sweet One” and “Cream One” have leaves that are middle sized  (@ 3.5 inches long X @ 2 inches wide).

          H. S. I. member, Mary Bleck, former co-owner of Abbey Gardens in California and later curator of the Johannesburg , S. Africa Botanical Garden once told me that when in doubt about an identity that is was better to treat the plant as a cultivar.  I think she was right.  I’m betting that most of the plants we all grow as Hoya carnosa, Hoya motoskei, and Hoya pubicalyx are cultivars.

          I’m not sure if the Code now allows the conservation of species names (at one time it only allowed Genus names to be conserved).  If it is now allowed and you don’t like the situation, perhaps the solution for you might be to conserve the names of the plants you want to be Hoya carnosa and Hoya motoskei.

          Sometimes I get the impression that “newbie” hoya growers spend their time counting spots on hoya leaves and when they find one with more or less spots than the last one counted that they expect it to have a different species name.  T’ain’t so!




 Letter #2:  I just read  IN Fraterna 18(3): 6 (2005) that Hoya coronaria was first published  in 1826 as Eriostemma coronaria. Is this true? If so, where can I find a copy of the publication? I also read that it has been returned to the Eriostemma  genus, after having been classed as a Hoya for some time.  Is this true?  --- 

-- ME!

                   Reply: NO WAY, JOSE!   1). Hoya coronaria was published in 1826 as Hoya coronaria  Blume. The publication where this can be found is, C. L. Blume’s Bijdragen tot de Flora van Nederlandsch Indie. It’s on page 1063.

           2). It was NEVER validly published as Eriostemma coronaria. 

           3). The name, Eriostemma wasn’t coined until 1913 and no one ever even suggested that it might be a genus until 2001.

           4).  In 2001, R. D. Kloppenburg and Ed Gilding tried to publish a Genus Eriostemma.

           5). Their publication was NOT VALID.


                 For proof of this, I suggest that you find a copy of Flora Malesiana Bulletin, Vol. 13, #1 (February 2002). Turn to page 91.

          There you will find two very informative entries. The first reads, “Kloppenburg, D. 2001. New synonyms and combinations, Fraterna, 14(1): 11-14.  Several names of a variety of hoyas follow.  Ending the paragraph is,  Eriostemma (Schltr.) Kloppenburg & Gilding, NOM. INVAL., as new genus hidden on p. 14! No specific combinations, not even for a type species.”

          The second entry reads,  Kloppenburg, D. & E. Gilding. 2001. Genus Eriostemma (Schlechter) Kloppenburg & Gilding. Fraterna 14/2: 1 – 4, illus – 15 new comb., ALL INVAL. (Art. 33.3); basionyms not mentioned, only referred to! See also Fraterna 14(1): (2001) 14 (Asclepiadaceae).


“Nom. inval.” means: “Name invalid” and “Names invalid.”


      Letter #3: What do you think of Mr. Green’s statement in the same issue of Fraterna that nematodes in the water of a city’s drinking water.  He claims that the public water systems comes from wells that contain nematode eggs. What is your take on that?  George Slusser

                Reply:  When I saw that I phoned my county agent and asked.  He gave me a long detailed lecture on nematodes, most of which I already knew.

                To make a long story short, he told me what I suspected which is, “It is possible that nematode eggs could exist in wells but not at all likely in municipal water supplies. Municipal water systems draw water from wells, rivers, lakes and reservoirs. It doesn’t go into city water mains directly from those sources.  It goes into treatment tanks, where it is treated with chemicals (iodine and chlorine are two kinds often used). From there it goes into storage tanks (usually atop towers where the sun beats down on it all day long).

                If the treatment and storage systems did not destroy nematodes most of us (especially those of us in areas with sandy soil) would have serious health problems from pin worms, which are also nematodes.  If the water treatment kills pin worms it will certainly kill other types of nematodes.

                 Potted plants get nematodes from sitting on the ground and from having rain water and hose water hitting the ground and splashing onto the soil in the pots.  Potted plants get nematodes from sitting in common trays with other pots of infected plants.  Nematodes from those plants wash out through the holes in the bottom of the pots when the plants are watered and travel to nearby pots.

                Potted plants also get nematodes from untreated private well water and from rain water collected in rain barrels.  Rain barrel water becomes infected with nematodes which are brought in by insects.  George Slusser discovered that, as a marine biologist when he was employed by fisheries,  trying to discover that was killing salmon.  My county agent also confirmed that insects carry nematodes with them so, if you water your plants from rain barrels, keep the barrels covered so that insects can’t get in the water.


      Letter #4  Do you believe that hoyas with yellow leaves are healthy hoyas?  Mr. Green seems to think so. ----  ----- Me.

          Reply:  No! Healthy hoyas, as most other plants, have green leaves.  Plants need chlorophyll. Yellow  leaves are deficient in chlorophyll.  A plant with a chlorophyll deficiency is not a healthy plant. Yellow leaves soon fall, leaving bare stems that may, if cut and put in soil or water, form roots, provided the stalk itself isn’t yet dead.

           Mr. Green has, in the past (in his catalogs and in his writing) claimed that the reason mainlanders have so much trouble rooting his plants is because his cuttings are from such healthy plants, having high levels of carbohydrates.  I cannot say that I’ve had any trouble rooting cuttings from Mr. Green but I’ve heard scores of others complain about it.  I suspect that when Mr. Green has sent cuttings to me, he sends ideal cuttings because he knows I’ll spread the word if he doesn’t. Of course, he hasn’t knowingly sent anything to me for many years.



      The reason for putting the photographer’s name in the middle of the picture is because this newsletter is being published on the World Wide Web.


      Every kind of unsavory character can be found on the World Wide Web and a large number of the crooks

have their own Hoya web pages.  They don’t take pictures themselves and many of them don’t even grow hoyas.  They are what is called in the trade, “Plant Brokers.”  They put out catalogs and list all the rare plants they ever heard of – some so rare that they are extinct (or never existed).  If they get an order for one, they go to someone else and try to make a trade for it.  If they manage that, the customer gets the ordered plant.  If not, they get a promise and a lot of aggravation.


          Since these lowlifes do not have any hoyas, they can’t take pictures of their own plants, so they go on line and download the pictures of others.  They then post them to their websites and claim them as their own.  To add insult to injury, they claim that they own the copyrights and threaten to sue us for using our own pictures. The authorities; the various internet providers and our legislators appear to ignore the situation so it is up to us to protect ourselves by making the pictures we post undesirable to picture thieves.


          If hoya thieves and hoya picture thieves weren’t such a bunch of sorry losers they’d rob banks instead of stealing hoyas and hoya pictures – there’s more profit in that!