Flora (pdf)

	Stinkhorns in Hong Kong
	Three new additions to the vascular plant flora of Hong Kong
	Sometimes common is not common!
	A new population of Popowia pisocarpa (Annonaceae) in Lam Tsuen
	What eats Ilex chapaensis fruits?
	Gemmae of the moss Octoblepharum albidum taken as food by spider mites

Sometimes common is not common !

by Cecily Law

Fissistigma glaucescens (Hance) Merr. belongs to Annonaceae, the custard apple family. It is a woody climber with a characteristic whitish abaxial leave surface separating it from other members of the genus. Although considered a restricted species locally (Xing et al., 2000), Fissistigma glaucescens is distributed in southern China (Fujian, Guangdong, Hainan & Guangxi), Taiwan, Vietnam and the Philippines (Li, 1991; Yang et al., undated) and is common in Guangdong (Li, 1991). Flowering in Hong Kong has not been documented. Mr. Chan Shu Tong, who has collected plant specimens for over 40 years, claimed that he has never seen this species flowering or fruiting (Chan, pers. comm.). Dr. Ng Sai Chit and Dr. Richard Corlett have also claimed that flowering has not yet been seen (Corlett, pers. comm., Ng, pers. comm.). Herbarium specimens in Hong Kong Herbarium and HKU Herbarium are without flowers and fruits. It is known that flowering occurs in China from January to September and fruiting almost all year (Li, 1991).

A trip to Wu Kau Tang with Roger Kendrick on 11 August resolved the mystery. Three plants of F. glaucescens were found a few meters apart, all in flower. A fourth plant, some 100 m distant, had no flowers. Fruits and flowers were collected on 15^th September. Subsequent visits to Tai Po Kau (10 November) and Shek Hang, Tai Mong Tsai Valley, Sai Kung Country Park (24 November) revealed further large specimens of F. glaucescens bearing fruits and a few flowers.

Studies have found that it may take 20 or more years for some perennial forest species to produce flowers (Taiz & Zeiger, 1991). Certainly, there are a lot of factors that trigger flowering generally, including vernalisation, water stress, photoperiodism and maturity (Taiz & Zeiger, 1991). Additionally, there has been an increase in suitable forest habitat since the Second World War. These factors, when combined, may explain why there was no previous flowering record of F. glaucescens in Hong Kong.

This unintentional discovery may be the first record of flowering for F. glaucescens in Hong Kong. However, it is just the beginning. Follow-up visits will continue to provide more information. Colour pictures will be available on the Porcupine! website.

Species: Fissistigma glaucescens (Hance) Merr., 1919 ; Melodorum glaucescens Hance, 1881; F. obtusifolium Merr.

Habitat: gully or ravine in forest, feng shui wood (Li, 1991; Xing et al., 2000)

Medicinal Uses: roots used as Chinese medicine, leaves used for brewing wine (Li, 1991). Recent studies extracted alkaloids from bark for treating muscular atrophy, hepatomegaly & hepatosplenomegaly (Wu et al., 1987; Wu et al., 1990; Lo et al., 2000).

Li, P.T. (1991). Annonaceae. In: Chen, F.W. (chief editor). Flora of Guangdong volume II. Guangdong Science & Technology Press, Guangzhou. pp.33-34.

Lo, W.L., Chang, F.R. & Wu, Y.C. (2000). Alkaloids from the leaves of Fissistigma glaucescens. Journal of the Chinese Chemical Society 47: 1251-1256.

Taiz, L. & Zeiger, E. (1991). Plant Physiology. Benjamin/Cummings Pub. Co., Redwood City, Califonia. p. 513.

Wu, Y.C., Lu, S.T., Wu, T.S. & Lee, K.H. (1987). Kuafumine, a novel cytotoxic oxoaporphine alkaloid from Fissistigma glaucescens. Heterocycles 26: 9-12.

Wu, Y.C., Kao, S.C., Huang, J.F., Duh, C.Y & Lu, S.T. (1990). Two phenanthrene alkaloids from Fissistigma glaucescens. Phytochemistry 29: 2387-2388.

Xing, F.W., Ng, S.C. & Chau, L.K.C. (2000). Gymnosperms and angiosperms of Hong Kong. Memoirs of the Hong Kong Natural History Society 23. 21-135.

Yang, K.C., Chen, R.S. & Poon, F.C. (undated).[楊國禎、陳永修、潘富俊]. 由台灣高士佛的稀有植物論恆春半島的植物區系]
http://www.tnl.org.tw/article/biogeo/kusku/kusku.htm (accessed 18 September 2002)