In the local mountains of Fukuoka Prefecture, Kyushu, Japan, there exists two miniature orchid plants that literally spend their lives hanging off the the edge of branches or even twigs of trees – most notably Japanese plum yew, Cephalotaxus harringtonia, Japanese cedar, Cryptomeria japonica. and to a lesser extent, hinoki cypress, Chamaecyparis obtusa. Mind you, these trees grow on exposed ridge lines that commonly experience typhoons (the Eastern equivalent of hurricanes) and near constant winds off the sea. Such a life is precarious to say the least, yet they manage to thrive. Both are closely related, but in different genera.
Thrixspermum japonicum is a miniature evergreen epiphytic orchid. The plant grows from one growing point (monopodial growth form) and has a trailing stem. Offshoots can grow off this stem, sometimes forming small clumps of pendulous growths. The entire plant is small with each growth being 3-10 cm in length, occasionally longer in really large specimens. The thin leaves are usually a deep purplish green, between 1-3.5 cm long and 0.5-1 cm wide. The light grey-green roots mostly grow off the leafless end of the stem and are 4-9 mm long and about 1 mm wide. The flower buds begin to form in late summer in small clusters, and stay in stasis throughout the winter months until opening in mid spring.
The flowers hang in clusters of 3-8, hanging neatly arrayed with all the flowers facing the same way. Each flower is tiny, not much more than 1 cm across and is a lovely creamy yellow. The flower is cupped forward, but mostly open, however the dorsal sepal stays bent forward over the lip. The sepals and petals are pure creamy yellow. The lip is heavily marked with reddish brown and is bulbous at its base with two flaring up swept “wings” at its sides. The seed pods are elongate and thin; 2-2.5 cm long and about 3 mm wide. Plants typically form small, loose colonies.
This species is locally abundant in wet forests growing on the twigs and small branches of conifer trees, especially Japanese cedar, Cryptomeria japonica, and Japanese plum yew, Cephalotaxus harringtonia. White it is also reported to grow on the trunks of evergreen broad leafed trees such as the Camphor tree, Cinnamomum camphora, I have not seen that locally. Plants tend to grow at fairly high elevations, from 400 m to 1000 m. They have been collected from Iwate Prefecture in the north of Honshu and all the way southward to Kyushu, Shikoku, and Yaku Island off the Kyushu’s southern coast.
This was the first epiphytic Japanese orchid I ever saw in the wild. I was a bit surprised to find it, especially where I found it. It was growing on the very outermost branches of a Cephalotaxus tree high up a mountain where winters get quite cold. Since then I’ve seen many more, with the vast bulk of these being on the forest floor attached to fallen twigs and branches. If this orchid had a job description it would read, “dangling precariously on small twigs high up in trees and falling to the ground” – and that is about the truth! I am constantly finding plants on the ground during my outings into the mountains. Whenever I see a recently fallen cedar branch, I always give it a close look.
Continue reading “Life on the end of a twig, two miniature orchids from southern Japan”