Saxifraga hispidula D. Don

Many plants from Sikkim have entire leaves (Saxifraga hispidula var. hispidula), but no such plants have been seen among specimens from China.

Stem usually branched, 4.5-22.5 cm tall, glandular pilose. Leaf buds present in axils at proximal nodes. Proximal cauline leaves caducous, less than 1/2 size of median ones, margin entire. Median cauline leaves subelliptic to ovate, 0.5-2 cm × 2.5-10 mm, both surfaces strigose, margin with 3-5 acute lobes toward apex. Flower usually solitary, or cyme 2-4-flowered; pedicel 0.6-2.1 cm, long glandular hairy. Sepals erect or somewhat spreading, ovate, 2.3-4 × 1.4-2.3 mm, glandular or eglandular hairy abaxially, adaxially distally, and marginally, veins 3-8, confluent at apex. Petals yellow, elliptic to broadly so or obovate, 4-7.3 × 2.9-5 mm, 2-16-callose, 3-10-veined, base contracted into a claw 0.6-1.7 mm, apex obtuse. Stamens 3-4.5 mm. Ovary subsuperior, ovoid to broadly so, 1.6-2.2 mm; styles 1.5-1.8 mm. Fl. and fr. Jul-Sep. 2n = 16, 24*.

C Sichuan (Baoxing Xian, Tianquan Xian), S Xizang, NW Yunnan [Bhutan, N India, N Myanmar, Nepal, Sikkim].

Himalaya (Garhwal to Bhutan), Assam, Burma, Tibet, W. China.

3300-4500 m

Rocks and rock crevices in forests, forest margins, scrub, alpine meadows, and on cliffs; 2300-5600 m.

Hirculus hispidulus (D. Don) Losinskaja; Saxifraga evolvuloides Wallich ex Seringe; S. hispidula var. dentata Franchet; S. hispidula var. doniana Engler; S. potentilliflora H. Léveillé.

Flowering and fruiting from July to September.

Saxifraga hispidula is close relative of Saxifraga substrigosa, but differs from the latter in its median leaves distributed evenly along stem (vs. aggregated, often into a rosette), each usually with 3 (or 5) apical lobes (vs. with several teeth), inflorescence branches 1-flowered (vs. 2- or more flowered).

Saxifraga hispidula is occurring in C Sichuan, S Xizang, NW Yunnan of China, Bhutan, N India, N Myanmar, Nepal, Sikkim.

Phylogenetic analysis of chloroplast sequence data derived from matK and rbcL was employed to examine relationships among sections of Saxifraga, the segregate genera Zahlbrucknera, Saxifragopsis, and Cascadia, and the relationships of these taxa to other Saxifragaceae sensu strict (Soltis et al., 1996). Results indicated that Saxifraga is polyphyletic, comprising two well-differentiated clades. One clade, Saxifraga sensu stricto, is the sister to the remainder of the family and consists of Saxifraga sections Irregulares, Heterisia, Trachyphyllum, Cymbalaria, Mesogyne, Xanthizoon, Porphyrion, Ciliatae, Cotylea, Ligulatae, Saxifraga, and Gymnopera. A second major clade of Saxifraga species, Micranthes sensu lato, comprises the large section Micranthes, as well as the segregate genus Cascadia, and S. tolmiei of section Merkianae.

Stem usually branched, 4.5-22.5 cm tall, glandular pilose. Leaf buds present in axils at proximal nodes. Proximal cauline leaves caducous, less than 1/2 size of median ones, margin entire. Median cauline leaves subelliptic to ovate, 0.5-2 cm long, 2.5-10 mm wide, both surfaces strigose, margin with 3-5 acute lobes toward apex. Flower usually solitary, or cyme 2-4-flowered; pedicel 0.6-2.1 cm, long glandular hairy. Sepals erect or somewhat spreading, ovate, 2.3-4 mm long, 1.4-2.3 mm wide, glandular or eglandular hairy abaxially, adaxially distally, and marginally, veins 3-8, confluent at apex. Petals yellow, elliptic to broadly so or obovate, 4-7.3 mm long, 2.9-5 mm wide, 2-16-callose, 3-10-veined, base contracted into a claw 0.6-1.7 mm, apex obtuse. Stamens 3-4.5 mm. Ovary subsuperior, ovoid to broadly so, 1.6-2.2 mm; styles 1.5-1.8 mm.

The chromosomal number of Saxifraga hispidula is 2n = 16, 24 (Wakabayashi, 1997).

Growing in rocks and rock crevices in forests, forest margins, scrub, alpine meadows, and on cliffs; 2300-5600 m.

Saxifraga hispidula là một loài thực vật có hoa trong họ Saxifragaceae. Loài này được D. Don miêu tả khoa học đầu tiên năm 1821.

齿叶虎耳草（学名：Saxifraga hispidula）为虎耳草科虎耳草属下的一个种。