Polystachya aconitiflora

Polystachya aconitiflora occurs epiphytically or occasionally lithophytically at elevations of 1650-3000m from Uganda, Rwanda, Zaire, and the Congo (Parsons and Gerritsen, 2013, p.807-808).  It is a easy-growing, compact species with the height of about 12cm (mine is about 10cm tall).  Although the flower is relatively small (about 1cm tall), it seems to flower most of the year.

The species name (species epithet) is from the similarity to the flower of monkshood (genus Aconitum). It was described in 1942 by Summerhayes (p.295-297), and the original description can be found in Biodiversity Heritage Library (link).  Podzorski and Cribb (1979) treated it as a variety of another species, Polystachya vulcanica var. aconitiflora. But more recent monograph seems to treat it as a separate species (Mytnik-Ejsmont 2011, Szlachetko and Mytnik-Ejsmont 2015). P. vulcanica is much bigger (both the plant and flower size), and the leaves are beefier (semi-terete) and longer (the plant hight of about 20cm), instead of shorter (plant about 12cm tall), flat grass-like leaves of P. aconitiflora.  It kind of looks like Cat Grass (i.e. Oat, Wheat, Barley etc).

There is a possibility that P. vulcanica and P. aconitiflora differs in chromosome counts. Two samples of P. vulcanica showed 2n=40 and approximately 62 while one sample of P. aconitiflora showed a possibly smaller counts of approximately 35 (Podzorski and Cribb 1979).  All of these samples were from Uganda.  The other species in this group has the base of 2n=40.  So the number of chromosomes in P. aconitiflora might have been reduced a little bit (these are called aneuploidy), but we need a bit more samples. Podzorski and Cribb (1979) noted that P. volcanic occurs in a higher elevation than P. aconitiflora in the Kigeze District of Uganda, but the altitudinal separation was not observed in other regions.

I obtained this from Afri-Orchids and have been growing it at the cooler-end of intermediate temperature.

The flower is about 1cm high, and the dorsal sepal (the bottom one) is 5mm long x 4mm wide.

Looking up into the flower.  The inside of the lip has nice purple spots.

It is a compact species, mine is about 10cm tall.  The leaves are grass like.

Literature Cited:

• Mytnik-Ejsmont, J. (2011). A monograph of the subtribe Polystachyinae Schltr. (Orchidaceae). Fundacja Rozwoju Uniwersytetu Gdanskiego.
• Parsons, R. and M. E. Gerritsen. 2013. A Compendium of Miniature Orchid Species. Volume 2.  Redfern Natural History Productions (link to the publisher's site).
• Podzorski A. C. and P. J. Cribb. 1979.  A revision of Polystachya sect. Cultriformes (Orchidaceae)  Kew Bulletin, 34 (1): 147-186
• Summerhayes, V. S. 1942. African Orchids. XII. Botanical Museum Leaflets, Harvard University 10 (9): 257-299.
• Szlachetko, D. L. & J. Mytnik-Ejsmont. 2015. Orchidaceae of West-Central Africa, Volume 2. Koeltz Scientific books, Koenigsheim, Germany.