Roscoea schneideriana

Roscoea schneideriana is a perennial herbaceous plant found in China, in Tibet, Sichuan and Yunnan. Most members of the ginger family (Zingiberaceae), to which it belongs, are tropical, but "R. schneideriana", like other species of "Roscoea", grows in much colder mountainous regions.
Description.
"Roscoea schneideriana " is a perennial herbaceous plant. Like all members of the genus "Roscoea", it dies back each year to a short vertical rhizome, to which are attached the tuberous roots. When growth begins again, "pseudostems" are produced: structures which resemble stems but are actually formed from the tightly wrapped bases (sheaths) of its leaves. Plants are tall with usually four to six leaves, although there may be as few as two. The leaves form a rosette at the end of the pseudostem and have narrow blades usually long by wide, usually curved (falcate), hairless (glabrous), and with a pointed tip.
Flowers appear in July to August in the wild. The stem (peduncle) of the flower spike (inflorescence) is either held within the leaf sheaths or sometimes slightly extended from them. The flowers usually open one at a time and are purple or white. The ellipse-shaped bracts which subtend the flowers are .
Each flower has the typical structure for "Roscoea" (see the diagrams in that article). There is a tube-shaped outer calyx, long, with a two-toothed apex. Next the three petals (the corolla) form a tube long, terminating in three lobes, an elliptical upright central lobe, about long and two similarly sized but somewhat narrower side lobes. Inside the petals are structures formed from four sterile stamens (staminodes): two lateral staminodes form what appear to be small upright petals, which are about long; two central staminodes are fused to form a lip or labellum, long by about wide. The labellum does not bend downwards and is split into two lobes for about half its length.
The single functional stamen has a yellow anther, about long, with long spurs formed from the connective tissue between the two capsules of the anther. The stigma is funnel-shaped.
Taxonomy.
"Roscoea schneideriana" was first described by Ludwig Loesener in 1923 as "R. yunnanensis" var. "schneideriana". ("R. yunnanensis" is now regarded as a synonym of "R. cautleyoides".) Jill Cowley raised it to a full species in 1982.
Evolution and phylogeny.
The family Zingiberaceae is mainly tropical in distribution. The unusual mountainous distribution of "Roscoea" may have evolved relatively recently and be a response to the uplift taking place in the region in the last 50 million years or so due to the collision of the Indian and Asian tectonic plates.
Species of "Roscoea" divide into two clear groups, a Himalayan clade and a "Chinese" clade (which includes some species from outside China). The two clades correspond to a geographical separation, being divided by the Brahmaputra River as it flows south at the end of the Himalayan mountain chain. It has been suggested that the genus may have originated in this area and then spread westwards along the Himalayas and eastwards into the mountains of China and its southern neighbours. "R. schneideriana" is in the Chinese clade, as would be expected from its distribution.
Distribution and habitat.
"Roscoea schneideriana " is found in Tibet, Sichuan and Yunnan, in China, growing at altitudes of in mixed forests, moist stony grassland and rocky mountain cliffs.