PS-The Hoyan

Volume 3, #1



Hoya mindorensis Schltr. – Photographed by George Slusser


Hoya erythrostemma  Kerr – Photograph by J. Donker


Letter #1:  

This one came from a Swedish reader.  She asked me to explain the differences between Hoya mindorensis  & Hoya erythrostemma.  She reminded me that Mr. Kloppenburg claims that they are one and the same and that the correct (oldest) name is Hoya mindorensis.  Being aware that I do not buy Mr. Kloppenburg’s lumping of these two species, she wanted me to explain why I disagree with him and she asked that I put it on PS-The Hoyan, so here goes!


In the 4th Quarter 1991 issue of Fraterna Mr. Kloppenburg attempted to sink  Hoya erythrostemma  Kerr into synonymy, making it Hoya mindorensis Schltr.  In this attempt he miscopied both original name publications, misspelling 8 Latin words in his reprint of Hoya erythrostemma and changing one of those Latin words from “stigmatis” (which is the fertile part of the female sex organ of a plant) as it was in the original, to the word, “segmentis” (which is a portion of something) in his blotched reprint. He also changed the word “circiter” (which means “around, in the neighborhood, near, about, approximately, etc.) to the non-word “cinter.” He misspelled an equal number of Latin words in copying the Hoya mindorensis publication but those weren’t so serious.

Accompanying this travesty was a page of 8 pictures.  Some of the pictures are of such poor quality that even the Almighty would be hard pressed to identify them by any but supernatural means. Those that are recognizable prove, without a shadow of doubt, that more than one species is pictured on that page, regardless of what the author of the piece alleges.  What surprises me most is the blind acceptance that he is correct (because that nice man, Mr. Kloppenburg says so) from the same people who go on hoya forums and question the identity of a common hoya because a single leaf on theirs is a different shade of green, pink or white, than others they’ve seen with the same labels on them.  Why can’t they see the radical differences in the flower parts on Mr. Kloppenburg’s  picture page? 

Here are my reasons for knowing that Hoya erythrostemma  is NOT a synonymous name for Hoya mindorensis:


Schlechter’s sketch of a Hoya mindorensis flower.


       Keep in mind the fact that this flower was dried and pressed before Schlechter ever laid eyes on it.

The most remarkable feature of this species is the pollinarium.  It is remarkable in that the outer margins of the pollinia are not keeled as in all other hoyas collected to date, except  this species, Hoya wightii and hoyas  in the Eriostemma section.  Schlechter did not pay a lot of attention to pollinaria so his sketches of them are always inaccurate in many ways but he drew all of his other hoya pollinia (except Eriostemmas)  with keels on their outer margins. They are missing in  his sketch of Hoya mindorensis.  These “keels” are called “wings” by Rintz and  sterile edges” by Kloppenburg). They are missing on the pollinia belonging to the pictured Hoya mindorensis.  They are present on the pollinia of Hoya erythrostemma.



Hoya mindorensis Schltr.

Tracings of photomicrographic pictures of actual flower parts.

a.  Calyx & carpels. 

            b.  Corona above; note the ridge down the center of each lobe for entire length and lack of any kind of division

      near or at outer lobal apex. 

c.   Corona lobe below; note thickened upper lobal margins that are lacking in Hoya erythrostemma. 

d.   Corona, side view. With the thickened lower side towards the center.  This is a lot more exaggerated than in

      Schlechter’s sketch but you must remember that Schlechter drew what he saw viewing flowers that had been

      put in a press and dried before he ever saw them.  My sketches are from living material. 

e.      Pollinarium. Note the lack of keeled outer margins on the pollinia.  Schlechter drew much longer translators

and no caudicles.  I believe that is because the pollinaria he saw had become twisted from front to back or visa versa.  Pollinaria are extremely difficult to work with --- they just won’t behave.  Those in my sketch were persuaded to lie flat, face up, for photographing but that took a lot of work to accomplish.  I also had fresh flowers.  I’ve seen it happen so often that I do not consider it speculation when I say that I’m sure Schlechter’s pollinarium twisted, causing the caudicle to slip out of the protective embrace of the translator.  This resulted in the long slender looking translator arm, sans caudicle. While I do not believe Mr. Kloppenburg’s oft repeated statement that one can identify a hoya by its pollinarium alone, I wonder why he confuses two with such different pollinaria.  He’s made the claim frequently and, to date, has never published a retraction of said statement, at least not in a way that one could recognize his statement as a retraction.


Hoya erythrostemma Kerr

Tracings of photomicrographic pictures of actual flowers.

a. Calyx & carpels, side view

b. Calyx & carpels, overhead view.

c. Corona above.  Note the scooped out lower third of the lobes and also the division at the apex of each lobe.

     This is lacking on Hoya mindorensis.

d. Corona, lower side.  Note that the inner lobal margins are flat.

e. Corona, side view.  This is similar to the side view of Hoya mindorensis  but the progression from thick in

    the center to thinner at the outside is more gradual.

f. Pollinarium. Note the opened toed bedroom slipper shape of the retinaculum, the very narrow translators and

the big, fat caudicles that are so different from those on Hoya mindorensis.  But more than anything, note that each pollinium is very strongly keeled on its outer margin. If you are familiar with the R. Rintz Hoya erythrostemma drawing in his 1978 Malaysian Hoya monograph, you’ll notice that he drew the pollinarium to look quite different than the one shown here.  His was an accurate drawing of the underside of a pollinarium.  My drawing is of the upper side.  Pollinaria are very difficult to work with so it is very easy to mistake the top from the bottom when one removes one for study, especially if one is in too big a hurry to repeat the process several times and continuously compare the view on the glass slide with the one still attached to the flower.

Letter #2: 

This letter was also sent by a Swedish grower (not the same one) who started out by saying, “This is a trick question.” She then asked, “Did you see Mr. Kloppenburg’s publication of the new species Hoya kastbergii in Fraterna 16(4): 1 (2002)?  Please tell me what you think is wrong with it.” In addition, Berit Carlgren also wrote and pointed out a grave error in that publication, so I was prepared with an answer, trick or not.


Yes, I found something wrong with Mr. Kloppenburg’s publication, as with all of Mr. Kloppenburg’s publications.  First off I don’t think it is a valid publication because he didn’t clearly identify the holotype specimen.  He merely said, “Holotypus 102003 (UC).”  Whose 102003 is it?  Kloppenburg’s?  Kastberg’s? or Joe Blowinski’s? Different collectors often have identical collection numbers on their specimens so I believe the collector’s name should have been cited. If you ever got a Kloppenburg sales’ list you will have noted his bad habit of dropping prefixes from numbered species.  He’d often have as many as three listings of a single number with no way for one to distinguish between them.  One would be an IML number; one would be an F number and one would be a Perpich number.  Customers were never given any indication as to which was which or even that each was a different species.  It’s no different in his publishing. 

The “trick question.” I think,  referred to Mr. Kloppenburg’s unresearched and uninvestigated statement that says, “Plant: has clear sap, grows like Hoya carnosa R. Br.” The fact is that this species has thick, sticky, juicy, snow white, opaque, milky looking sap!   All one needs do is nick a leaf with a fingernail --- even a thin, brittle, “breaks with a cross look,” fingernail (that’s the kind I have) will do it.  As for it growing like Hoya carnosa, it certainly isn’t, at least under my conditions, the strong, rampant grower that Hoya carnosa is, however it does root and grow when planted in dirt or a dirt substitute so in that sense he is correct.  It grows like Hoya carnosa   ---- and all other plants.

Another thing I found strange is that he tells you the plant grows in nature as an epiphyte and then in the next sentence he tells you,  The ground there is limestone.”  What the heck difference does it make what the ground is if it is the nature of the plant to grow high above the ground in a tree, where its only nourishment comes from rotting leaves and bird and insect waste?  Such a statement implies that the plant should have limestone added to its potting soil and that is probably not true.  I grow the plant and it is thriving in a slightly acid mix.

_ _ _ _ _ _ _ _ _ _


NOTICE:  Contrary to what you may have read in a letter by an uniformed writer on Garden Web, my permission to copy and use the text on this web page, does NOT extend to anything else ever written by me, nor to any other web site of mine, or one to which I have contributed. You may quote me but you must credit me. Plagiarism is not only unethical.  It is illegal.


For Sale - Auction

Complete set of the best houseplant publication ever!!

Houseplants & Porch Gardens Magazine

Only 39 issues were published, much to the sorrow of all of its subscribers.


The reason for its demise was that all of its competition was floundering and the publishers thought that by buying such magazines as Plants Alive and Popular Gardening, Indoors that it could double or triple its list of subscribers.  That didn’t happen.  Agreements were made to honor all of the remaining time of the subscribers to those publications.  What Houseplants & Porch Gardens didn’t realize was that all of these magazines had the same list of subscribers.  That meant that in most cases, when Houseplants & Porch Gardensoriginal list of subscribers’ renewals came due, they’d be sending no money because their unfilled subscriptions to the other two magazines had to be added.  With no renewal money coming in and having just paid a big chunk of money for the competition, the magazine had no choice but to fold.

This magazine was published from Mid-1976 until Mid-1980.  There were 39 issues.

The only things not up to date in these publications are some of the advertisers (gone out of business) and some of the pest controls recommended (banned so no longer  available).

Bidding starts at $150.00. Buyer pays shipping charges.  Chose your shipper and tell them the package weighs @ 240 lbs.

Send bids via snail mail to: Christine M. Burton,  261 Blue Heron Dr., Monticello, GA 31064-3611

Sorry, I will not sell single copies – it’s all or nothing.  No CODs.  No foreign shipping. No credit card payments.  Personal checks or money orders are okay!  Will ship when check clears.