3. Hypnum circinale Hook. 拳卷叶灰藓 quan-juan-ye hui xian
Musci Exot. 2: 107. 1819. Drepanium circinale (Hook.) Roth, Eur. Laubm. 2: 617. Pl. 42, f. 7. 1904. Stereodon circinalis (Hook.) Mitt., Trans. Linn. Soc. London, Bot., ser. 2, 3: 181. 1891. Type: South America.
Stereodon sequoieti (C. Müll.) Broth. ex Par., Coll. Nom. Broth. 32. 1909. Hypnum sequoieti C. Müll., Flora 58: 91. 1875.
Plants small, slender, yellowish green or yellowish brown, glossy. Stems creeping, 3–5 cm long, sometimes up to 10 cm long, with reddish brown rhizoids at base, densely regularly pinnately or bipinnately branched; branches flattened, 2–7 mm long; central strand not developed; pseudoparaphyllia filamentous or narrowly lanceolate. Stem leaves and branch leaves similar, falcate-secund or circinate, 1.5–2.2 mm × 0.5–0.7 mm, broadly elliptic- or triangular-lanceolate, asymmetric at base, gradually to slenderly acuminate, concave; margins recurved on one side, serrulate; costae weak, indistinct; median and upper leaf cells linear, 60–80(–100) µm × 4–5 µm, thin- or thick-walled, porose; basal cells shorter, thick-walled; alar cells few, subquadrate or rounded quadrate, with 2–5 rows of reddish brown cells, sometimes hyaline at margins. Dioicous. Inner perichaetial leaves erect, oblong-lanceolate, plane, serrulate at margins. Setae 0.6–1.5(–2.0) cm long, twisted when dry; capsules ovoid to oblong-ovoid, horizontal to inclined, 0.8–1.5 mm long, not constricted below the mouth when dry; opercula conic, shortly rostrate; annuli developed in 1–2 rows; peristome teeth normal, with 1–2 cilia. Spores 15–18 µm in diameter, minutely papillose.