Anthoceros alpinus Steph., Sp. Hepat.

Peng, Tao & Zhu, Rui-Liang, 2013, A revision of the genus Anthoceros (Anthocerotaceae, Anthocerotophyta) in China, Phytotaxa 100 (1), pp. 21-35 : 23-24

Anthoceros alpinus Steph., Sp. Hepat. 6: 425. 1923.

Type :— INDIA. Oriental. Mussoorie, ca. 7000 ft., October 1879, J. F. Duthie s.n. (holotype G-12759!) .

Thalli medium-sized, in rosettes, ecostate, thallus lobes tapering, up to 6 mm long and 4 mm wide at apex, spongy. Nostoc colonies uncommon, scattered across the ventral side of thallus. Dioicous (?). Antheridia not seen. Involucre cylindrical, erect, up to 3 mm high, smooth at mouth. Capsules frequent, up to 3 cm long, bivalved, with well-developed columella. Epidermal cells of capsule walls rectangular to narrow rectangular, 36–197 × 9–29 µm, thick-walled, stomata scattered, 42–70 × 40–44 µm, each stoma with two reniform guard cells surrounded by 5–7 cells; cells of the inner lining layer of capsule walls rectangular, 27–100 × 26–50 µm, sometimes with irregular dark thin bands on tangential walls. Spores blackish-brown, 40–61 µm in diameter, sporoderm with closely studded blunt projections forming a reticuloid-semireticulate pattern, proximal face with a prominent trilete mark bordered by a distinct unsculptured streak, 2–8 µm wide. Pseudoelaters blackish brown, 93–146 µm long, usually 2–4 cells long, cells narrowly rectangular, mostly 25–58 × 10–24 µm, thin walled, sometimes with irregular thickenings.

Anthoceros alpinus was first collected by J.F. Duthie from Mussoorie of India in 1879 ( Stephani 1923). It seems that no more collections were made until Asthana and Nath (2004) rediscovered it from Nainital of India in 1991. Due to development, especially the road construction, A. alpinus is threatened with the loss of habitat, and has been added to the critically endangered list of India bryophytes by Singh (2008). Here, we report this species ( Fig. 1 ) as a new record to China. The collection was made by D.G. Long at an altitude of 2653 m from Yunnan in 1990.

The length of pseudoelaters in Anthoceros alpinus is variable; pseudoelaters from the type specimen are 65–97 µm long, but they are usually 93–146 µm long in Chinese material ( Fig. 1 B ). Under the scanning electron microscope (SEM), the proximal surface of spores of A. alpinus exhibits a conspicuous trilete mark bordered by an unsculptured streak ( Fig. 1 C ). The sporoderm has a distinct semi-reticulate pattern comprising prominent ridges ornamented with blunt and round-headed projections ( Fig. 1 D ). These ridges form imperfect reticulations enclosing lumina and pits at some places. The sporoderm is clearly devoid of any sharp projections over the irregularly running ridges which enclose variously shaped lumina all over its surface.

Although three taxa of Anthoceros in China, A. alpinus , A. bharadwajii and A. fusiformis var. taiwanensis resemble each other by the sporoderm ornamentation with distinct smooth strips along the trilete mark, A. alpinus is easily distinguished by spore characteristics as described above. Anthoceros bharadwajii possesses a reticuloid-pseudolamellate sporoderm on small spores (35–54 µm in diameter). Anthoceros fusiformis var. taiwanensis is characterized by scattered spinate to spinulate outgrowths that are united at the base on the proximal surface of spores, and spinate to spinulate lamellae on distal ornamentation ( Hasegawa 1993b).

Habitat: —Known only on soil in temple grounds, at 2635 m in China and roadside ridges in temperate habitats between 2100–2350 m in India.

Distribution: — China (Yunnan) and India.

Representative specimen examined: — CHINA. Yunnan: Yulong Naxi Autonomous Co., Camellia Temple N of Lijiang, on shady wall in temple grounds, 2635 m, 9 October 1990, D. G . Long 18961 ( E) .

Figures

FIGURE 1. Anthoceros alpinus Steph. A. Thin-walled epidermis of capsule with stomata. B. Pseudoelater with thin-walls and irregular thickenings. C. SEM (scanning electron microscope) micrograph showing proximal spore face with a prominent trilete mark and narrow surrounding strip that is ornamentation-free (smooth). D. SEM micrograph showing distal face of spore with semireticulate pattern comprising ridges ornamented with blunt and round-headed knobs. All from D.G. Long 18961 (E). Scale bars: A=50 µm; B=20 µm; C, D=10 µm.