中国水玉簪属Burmannia L.区系特征的初步研究

A Preliminary Study on the Floristic Features of the Genus Burmannia in China

The genus Burmannaia is one of the largest genera in the Burmanniaceae, of which12 species have been recorded in China.  It is mainly a tropical genus.  The speciesin China are all confined to the region south of Yangtze River. They are distributedchiefly in the provinces Guangdong (9 species) and Yunnan (6 species). After havingstudied the areas of all the species in China, we are able to classify them into follow-ing 4 area-types:     1.  Area-type of Tropical Asia to Tropical Australia. The two non-saprophyticspecies (Burmannia disticha, B. caelestis) and one saprophytic (B. championii) belongto this area-type.  It is an ancient type.  The plants of this type mostly have a wideecological amplitude, for example, B. disticha may be found in tropical and subtropicalregions.  The plants occur not only in evergreen forests, in bushs, but also in ratherarid herbosa and on the side of streams (Fig. 2).    2. Area-type of Tropical SE Asia.  In the type are 3 saprophytic species i.e.B. oblonga, B. wallichii and B. nepalensis.     3. Area-type of E. Asia.  (Fig. 3) Burmannia in China with E. Asian distribu-tion is poor in species.  There are only 2 saprophytic species. B. cryptopetala is distri-buted in Haina (China), Kyushu and Honshu (Japan); B. itoana occurs in Taiwan(China), Riukiu and Kyushu (Japan).  They are known only on the islands of E. Asia.Such a pattern of distribution may suggest connection of these islands once in the prehistoric time in spite of their present isolation.     4.  Endemic area-type. (Fig. 4).  Here are 3 saprophytic species and one varietywith green leaves.  B. nana occurs only in E. Taiwan.  One of the two new speciesdescribed by present author in this paper, B. fadouensis, is known from Xichou Xiao,S. E. Yunnan, to Longzhou Xian of the province Gaunxi; the other one, B. pingbien-ensis occurs only in Pinbien Xian of S. E. Yunnan. The last species is endemic to China.B. pusilla var. hongkongensis is non-saprophytic and known from the province Guang-dong and its bordering islands.  Both B. fadouensis and B. pingbienensis are characte-rized by the axillary bulbils, which enable them to adapt to rather arid and cold condi-tions in northern part of the tropical region.