Sendtner's Molendoa Moss

The perichaetial leaves of Molendoa sendtneriana reach 1.7 mm, little more than half the length of those of M. hornschuchiana. The phenomenal range of variation in leaf length and shape matches that of Dichodontium pellucidum (Dicranaceae). Because M. sendtneriana has the appearance of a Didymodon, it is important to examine the collection carefully for the distinctive lateral perichaetia (terminal in Didymodon). Both M. sendtneriana and Anoectangium aestivum have the distinctive lateral perichaetia, but large plants of the former have two stereid bands, and small plants have a costa ending below the apex and also often have leaves with 2-stratose portions, features that are absent from the latter in the flora area. The most distal leaves of M. sendtneriana are commonly a deep green and constrast strongly with the tan proximal portions of the turf. The lateral perichaetia, when present, will distinguish this species from Hymenostylium recurvirostrum, which grows commonly on the same substrate; when absent, the commonly elongate distal leaf cells in the leaf mid portion and the lack of an adaxial costal epidermis of the latter species (in the flora area) are helpful distinguishing traits. When sterile, Gymnostomum aeruginosum is similar to M. sendtnerianum but has smaller laminal papillae, mostly 3-5 per cell, and smaller leaf cells. Often plants of M. sendtneriana are encrusted with a distinctive black substance distally. Variation in leaf size and shape is substantial (see R. H. Zander 1977); usually the leaf apices of large plants are acute and those of small plants are obtuse.

Plants rather robust, to 5 cm high, bright green to yellowish green, or dark green, in loose tufts. Stems erect, usually branched; central strand weakly to well differentiated. Leaves appressed to somewhat involute when dry, erect-spreading when moist, linear-lanceolate, 1.3–2.1(–3.0) mm x 0.2–0.3(–0.5) mm, gradually acuminate at the apex; margins entire; costa stout, percurrent to shortly excurrent; upper leaf cells irregularly rounded-hexagonal, 6–12 µm x 5–10 µm, with several simple papillae; basal cells rectangular, 12–36 µm x 6–14 µm, smooth, more or less hyaline. Dioicous. Perichaetial leaves ovate-lanceolate. Setae 3.5–5.5 mm long, reddish yellow, not twisted; capsules erect, obovoid.

Stems to 2.5[-7] cm, sclerodermis present. Leaves ovate, ligulate, elliptic or short-lanceolate, (0.3-)1-2(-2.5) mm, entire; leaf base usually not differentiated in shape but occasionally widened and ovate; costa ending 1-3 cells before the leaf apex (blunt-leaved plants) or percurrent or short-excurrent as a stout mucro, rounded to semicircular in section at mid leaf, guide cells 2-4; distal laminal cells usually subquadrate, occasionally triangular or transversely elongated, 1:1-2; often 2-stratose marginally or in patches medially.

Distribution: China, Japan, India, Central Asia, Russia, and Alaska.

Habitat: on rocks and soil.

Hymenostylium formosicum Broth. & Yas., Rev. Bryol. 53: 1. 1926. Syntypes. China: Taiwan, Mt. Dai-bu, A. Yasuda 607; Taito, A. Yasuda 638. Hyophila grandiretis Sak., Bot. Mag. Tokyo 62: 105. 1949. Type. China: Shanxi (Shansi), Tai Hyi Zhen, Shizui, M. Sato 51 (isotype YNS). Molendoa roylei auct. non (Mitt.) Broth., Nat. Pflanzenfam. I(3): 391. 1902.

Anoectangium sendtnerianum Bruch & Schimper, Bryol. Europ. 1: 91. 1846; A. incurvans (Bescherelle) E. B. Bartram; A. obtusifolium (Cardot) Grout; A. sendtnerianum var. tenuinerve (Limpricht) Mönkemeyer; A. tenuinerve (Limpricht) Paris