Anthorrhiza caerulea and chrysacantha in cultivation

[Frank]

 

In 2017 I received a packet of seeds labeled as Anthorrhiza caerulea.  I sowed them and got good germination.   There was some variation in the seedlings and young plants but all were making large asymmetrically branched spines on both the caudex and stem - what was not to like about that!

In 2018 and 2019 I sold some of the plants on the American eBay using the name on the seed packet, Anthorrhiza caerulea.  "Caerulea" is derived from a Latin word meaning blue in reference to the fact that this species has beautiful blue flowers.  My first plant bloomed in September of 2020 and is pictured here.

 

The far right plant in this next photo is my A. caerulea plant again - note the raised, bold nature of the leaf veins on the underside of the leaves.

 

By the time I took this photo it was obvious that the other plants I still had from this sowing were not A. caerulea.  They are the two smaller plants in the above photo.  They have more elongated narrower leaves, and the veins on the underside are not bold and outstanding. 

Then I got an email from Ken Howell (a Forum member) who had bought one of my eBay supposedly A. caerulea plants. He was wondering why his plant had flowered with 2 inch long pure white flowers and not the expected blue flowers?

Ken did an excellent job of growing these plants!   Here is a great photo of his most recent blooming and fruiting event.  Note the asymmetrically branched spines, especially on the stem, the large white flowers and the unusual fruit color.

 

 

With Ken's information and photo, and with reference to  the "Huxley and Jebb article on the genus Anthorrhiza" on the internet, it is obvious that this is not A. caerulea but is in fact Anthorrhiza chrysacantha. The yellow-orange fruit color is a nice confirmation of the ID.

Turns out that these two species live as epiphytes in the same mountain forests in PNG.  That would account for the mixed seeds I had in my seed packet.

So, if you acquired one of my "A. caerulea" plants from me in 2018 or 2019 and your plant looks like Ken's photo here you will need to change your plant's label to A. chrysacantha.

If you are growing either of these species I suggest you look at the drawings in this article that you can find on the internet with a Google search:  "Huxley CR, Jebb MHP. 1991. The tuberous epiphytes of the Rubiaceae 2: The new genus Anthorrhiza".  The drawings of both species show the stems and caudexes entirely covered with dense spinage.  It is going to be exciting watching the spines filling in as these plants mature.  (You can also see photos of "full spinage" in the posting by Andreas titled "Anthorrhiza chrysacantha" slightly below this posting in this Anthorrhiza section of the Forum)

Let me also note that in 2018 Andreas Wistuba sold seedlings of a plant he called A. chrysacantha from Mt. Kaindi in PNG.  I am growing one of these and it is chunkier than the chrysacanthas I have, currently has little spinage and reminds me more of a M. horrida.  I am waiting for it to flower so I can study it and discuss it further.

(Ken's photo of his A. chrysacantha plant is used here with his written permission. The other 2 photos are mine.  As per Forum policy reuse of any photos here require written permission of the original photo owner.)