The entry today was authored by Taisha, who writes:
Today's photos of Disperis johnstonii (image 1 | image 2) were taken by Bart Wursten in the Cheringoma limestone gorges of Mozambique on April 17, 2013. He notes that according to any literature he's investigated that this is the first time this species has been recorded for Mozambique. Thank you Bart for the many photos uploaded to the Botany Photo of the Day Flickr Pool, and for today's pictures!
Disperis johnstonii is a terrestrial orchid that grows up to 15cm. Plants typically grow in rich humus or sandy soil in grassy places under trees, often shaded by rocks. This species is widespread in tropical Africa, occurring in Nigeria, Cameroon, Tanzania, Malawi, Mozambique, Zambia, and Zimbabwe.
There are about twenty thousand species in the Orchidaceae. The morphology of orchids is quite diverse, however they typically have a floral anatomy made up of an outer whorl of three sepals, an inner whorl of two petals & labellum or lip, and a column made up of the stigma and pollinia. The genus Disperis is a group of orchids with a unique floral structure of having spurred lateral sepals and a reflexed labellum bearing an appendage.
Disperis johnstonii's flowers have yellow dorsal petals and a sepal (which are noted to sometimes be purple in East Africa) that form an open hood. The lateral sepals are white or very pale mauve with a spur-like depression in the centre. The labellum is curved back onto itself, with a pappilose appendage near the base and a papillose protuberance near the centre of its rounded apex. In the close-up photo, you can see it is covering the column. This species grows from ovoid-globose tubers with 2-3 alternate and ovate leaves that clasp the dark green stem at the base.