9. Ptychomitrium wilsonii Sull. & Lesq., Proc. Amer. Acad. Arts. 4:277. 1859.
Brachysteleum evanidinerve Broth., Sitzungsber. Akad. Wiss. Wien Math. Nat. Kl. Abt. 1, 131: 211. 1923. Type. China: Hunan, Chang-sha City, Handel-Mazzetti 12783 (holotype H-BR).
Plants medium-sized to rather large, 2–3(–4) cm high, green above, black-green below, sometimes black-brown throughout, in loose tufts. Stems simple or sparsely branched; central strand well developed. Leaves 3.9–4.1 mm long, incurved when dry, spreading to erect-spreading when moist, oblong-ovate to broadly oblong-lanceolate, slightly keeled or plane above, broadly acute or obtuse at the apex; margins plane, irregularly toothed in the upper half ; costa single, strong, gradually narrowed above, subpercurrent or ending just below the apex; upper leaf cells obscure, rounded quadrate to subquadrate, 10–13 µm wide, with slightly thickened walls; basal cells elongate, 35–70 µm x 8–11 µm, hyaline, thin-walled; alar cells often brownish. Autoicous. Perichaetial leaves similar to the upper stem leaves. Setae straight, yellow, ca. 4.5 mm long; capsules erect, ovoid to oblong-ovoid, ca. 1.5 mm long; annuli undifferentiated; peristome teeth lanceolate, split into 3–4 divisions nearly to the base, yellow above, reddish brown below, finely papillose throughout; opercula conic-rostrate, with a long, erect beak. Calyptrae mitrate, covering the middle to lower part of capsules, longitudinally plicate, lobed at base. Spores yellowish green, 25–30 µm in diameter, finely papillose.
Chinese specimens examined: ANHUI: Huang Shan (Mt.), D.-K. Li 891 (SHM). FUJIAN: Ku-shan, near Fuzhou (Foochou) City, H.-H. Chung B203 (as P. dentatum, FH); Wuyi Shan (Mt.), D.-K. Li 17703 (SHM); Nan-ping Co., C. Gao & Z.-W. Aur 25568 (IFSBH). Yong-chun, D.-K. Li 10553 (SHM). GUANGDONG: Ru-yuan Co., B.-J. Lin 579 (IBSC); Loh-fau Shan (Mt.), Merrill 11173 (as P. dentatum, NY); Hui-yang Co., W.-T. Tsang 25649 (as P. polyphylloides, FH). GUANGXI: Long-sheng Co., Jin & Hu 400 (IFSBH). GUIZHOU: Jiang-kou Co., Tan 91-680 (FH). HAINAN: Diao-lou Shan (Mt.), Reese 17928 (NY); Lin-shui Co., Redfearn 36211 (ALTA, MO, NY, SMS). HUNAN: Yi-zhong Co., W.-T. Tsang 13419 (as P. dentatum, NY). JIANGSU: Ming-ling, M. Zang 59 (HKAS); Nan-jing City, Y.-E. Yang 921 (BM). JIANGXI: Jing-gang Shan (Mt.), C.-H. Gao 25685 (SHM). ZHEJIANG: De-qing Co., P.-C. Wu 1228 (MO); Fu-yang, D.-K. Li 206 (SHM); Hang-zhou City, M. Zang 854 (HKAS); Jiu-long Shan (Mt.), R.-L. Hong & Z.-L. Liu 651 (HSNU); Yan-dang Shan (Mt.), D.-K. Li & C.-H. Gao 7955 (SHM); Xi-tian-mu Shan (Mt.), D.-K. Li 3727 (SHM); Ning-bo City, D.-K. Li 5815 (SHM); Tian-ta, D.-K. Li 6623 (SHM).
Habitat: on rocks or thin soil over rocks, sometimes rocks near streams; Distribution: China, Korea, and Japan.
Ptychomitrium wilsonii is closely related to P. dentatum. It can be distinguished from the latter by the following character states: 1) leaves broader, oblong-ovate to broadly oblong-lanceolate, with obtuse or broadly acute apices; 2) capsules broader, ovoid to oblong-ovoid; 3) peristome teeth lanceolate, deeply cleft into 3–4, unequal divisions; and 4) spores large, 25–30 µm in diameter.
Ptychomitrium wilsonii shows some variations in leaf shape. Most specimens have leaves with ovate bases and obtuse apices, while others have leaves with relatively narrow, oblong bases and broadly acute, sometimes nearly acute apices. The latter leaf shape is similar to that of P. dentatum. Under these circumstances, the sporophytes are useful for identification.
Illustrations: Pl. 145, figs. 1–9.