Comments on the Moss Genus Horikawaea (Pterobryaceae) in China

Abstract

The southeastern Asiatic genus Horikawaea, including two species-H. nitida Nog. and H. dubia (Tix.) Lin - occurs in China, from southeastern China southwards, and west to Xizang. A key, illustrations, and map are provided for the two species. The genus Horikawaea was first described by No- guchi in 1937, and presently includes two species. Horikawaea nitida Nog., the type species, was orig- inally described from Taiwan and was reported from Fujian Province, China, by Wu et al. (1981), while the second species of the genus, H. dubia (Tix.) Lin has been reported from northern Vietnam, Minh- Binh Province (Lin 1984a). In 1985 Luo reported H. nitida from Xizang Province, China. However, Lin determined later that the specimen (Lang 466, PE) was better referred to H. dubia (Lin 1986a). Also, Lin (1986b) recorded H. nitida from Assam (India) with a question mark. Further collections from southwestern China have been made since these original reports. In this paper, both species of Horikawaea can be reported from southwestern China. Specimens of this genus from Jingxi County in Guangxi Province (Hu, Shun-shi 46) have small plants with strongly complanate leaves arranged in four ranks. The plants have bul- bils on the apical portions of the leaves and alar cells with poorly developed wall thickenings. Other specimens from Xizang, Guangdong, Fujian, and Guangxi Provinces consist of large or medium-sized plants that are little complanate, with eight ranks of leaves. The alar cells have obvious wall thick- enings and the bulbils are located along the stem below the apex. These specimens represent two sep- arate species in the genus Horikawaea. They can be distinguished by the following key. Plants small, strongly complanate; leaves in four dis- tinct ranks; bulbils present at apex of leaves; alar