Tricyrtis ohsumiensis MASAM. - Liliaceae - Plant Profile

An online research

Author: Masamune, Genkei (1899-1993)
Commonly misspelled as Tricyrtis oshimensis

from bethchatto.co.uk

Synonym: Tricyrtis flava subsp. ohsumiensis (Masam.) Kitam., Coloured Ill. Herb. Pl. Jap. 3: 146 (1964).
Distribution: S Japan (Kyushu: Ôsumi Pen.) 38 JAP (GPS area: 31.21N, 130.62E)

Description by Beth Chatto:
An exotic-looking plant for cool, shady conditions and damp leaf-mould soil. Forms clumps of many stems with pairs of rich-green, pointed leaves facing opposite ways are wrapped round the stem, each forming a cradle for butter-yellow, lily-like flowers 5 cm. across, faintly peppered with red. Protect from slugs in early spring. Height 61 cm

Description by Crûg Farm:
A delightful relatively small species originating from Kyushu southern Japan. Forming a stocky plant with stem-clasping waxy leaves which are heavily blotched hiding the stems (20-30cm tall extending to 50cm after flowering). The upward facing sizeable pale yellow spotted flowers are borne in the axils August-September. Best cultivated in a humus rich leafy but well drained soil in full-part shade.

I found a good looking map of Japan and added the origin of Tricyrtis ohsumiensis, according to the Global Biodiversity Information Facility.

Map of Japan edited with Tricyrtis ohsumiensis distribution added

To find out more about the original climate of Tricyrtis ohsumiensis I looked up climate data of the Ibusuki, Kagoshima area in S Japan. (Data provided by WorldWeatherOnline.com, also with help from climate-data.org)

Reported min./max. temperatures for the past eight years have been during winter 4°C/13°C and 22°C/34°C for the summer. This concludes to an average annual temperature of 18.4°C in Ibusuki. The rainfall there averages 2310mm. Annual humidity varies between 70-85%. This climate is considered to be "Cfa" according to the Köppen-Geiger climate classification. "Cfa" translates to Humid Subtropical Climate. England is classed as "Cfb" Oceanic Climate with average annual temperatures around the 11°C mark and annual precipitation between 650 and 900mm. Despite the subtropical origin of Tricyrtis ohsumiensis, it is considered hardy in most of the UK.

The original habitat suggests woodland conditions with rich, moist soils and plenty of leaf litter or organic material. Simone Armer writes in her travel blog a fascinating description of climbing up Mt. Kaimondake, which overlooks Ibusuki with breathtaking views of Lake Ikeda. Worth a look to get an idea of the southern Japanese geography.

Hiking Mt. Kaimondake, Ibusuki by SimoneArmer.com

In comparison to the descriptions above, the original publication has been made in the Journal of the Society of Tropical Agriculture. [Nettai nogaku kwaishi]. Taihoku [Taipei] - J. Soc. Trop. Agric. 2: 41 1930, superseded by J. Agric. Assoc. China (Taipei). Below is a snippet of an original publication of Flora of Japan : in English : combined, much revised and extended translation / by the author of his Flora of Japan (1953) and Flora of Japan, Pteridophyta (1957) ; edited by Frederick G. Meyer and Egbert H. Walker.

Flora of Japan (1953) - biodiversitylibrary.org

Tricyrtis ohsumiensis Masam. TAKAKUMA-HOTOTOGISU.
Stems 20-50cm long, nearly glabrous; lower leaves oblong-lanceolate, acute, the upper elliptic to oblong, clasping, abruptly acute, 5-20cm long, 2-6cm wide, glabrous; flowers axillary and terminal, one or 2, yellow, nearly spotless, 2.5-3.5cm long, the pedicels slightly shorter to longer than the flowers, the tepals narrowly obovate or obovate-oblong, about 1cm wide, the inner segments slightly narrower. Sept.-Oct. from Kyushu (Osumi Prov.) S Japan.


As I gather more of my own experience and photos I will of course add those to this blog too. And another entry on my bucket list: travelling to Japan.