Tropicos | Name - !Didymodon hampei R.H. Zander

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!Didymodon hampei R.H. Zander

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Project Name Data (Last Modified On 2/15/2011)

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Project data (Last Modified On 2/15/2011)

Discussion:

Didymodon hampei (better known as Gyroweisia obtusifolia) is similar to Trichostomopsis australasiae in having abruptly enlarged and bulging, thin-walled, hyaline, smooth basal leaf cells. Trichostomopsis australasiae differs from D. hampei in having bistratose leaf margins, a costa with a single (dorsal) stereid band, and enlarged, quadrate, papillose ventral superficial costal cells. The leaves of Trichostomum brachydontium and D. hampei are similar in shape and areolation, but T. brachydontium differs in having a stoutly excurrent costa. Weisiopsis oblonga and Luisierella barbula are similar to D. hampei in size, habit, leaf shape, and in having abruptly differentiated basal leaf cells. They differ from D. hampei in having leaf cells that are mammillose-bulging ventrally and dorsally smooth. Hyophiladelphus agarius has the same type of sexual system as D. hampei as well as very short stems that are densely radiculose at base. It differs from D. hampei in having smooth leaf cells.

Illustrations: Magill (1977, Figs. 14–15); Sharp et al. (1994, Fig. 185). Figure 23.

Habitat: On rocks along roads; elevation not given.

Distribution in Central America: GUATEMALA. Alta Verapaz: Türckheim [6694] (NY). COSTA RICA. Guanacaste: McQueen 5060 (MO).

World Range: Mexico; Central America.

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Didymodon hampei Zand., Bull. Buffalo Soc. Nat. Sci. 32: 162. 1993, nom. nov.

Trichostomum obtusifolium Hampe, Bot. Zeitung (Berlin) 28: 49. 1870, hom. illeg., non P. Beauv., 1805. Gyroweisia obtusifolia Broth., Nat. Pflanzenfam. 1(3): 389. 1902. Husnotiella obtusifolia (Broth.) Zand., Bryologist 80: 265. 1977, non Didymodon obtusifolius Schkuhr., 1828. Protologue: Mexico. pr. Veracrucem ad saxa calcarea, leg. Strebel. (holotype BM, Zander 1977).

Gyroweisia papillosa Thér., Smithsonian Misc. Collect. 85(4): 6. 1931, non Didymodon papillosus (Dicks.) Brid. 1806. Protologue: Mexico. Michoacán, Morelia, Arsène 4927 (lectotype PC, isotype FH, Zander 1977).

Plants small, dull, greenish brown, in scattered tufts, to 2 mm high. Stems red, erect, unbranched, hyalodermis not or weakly differentiated, central strand present; rhizoids dense at base of stems. Axillary hairs 5–6 cells long, basal cell brown. Leaves 1.5–2 mm long, ligulate to oblong-ligulate, crowded, incurved, twisted and curled when dry, spreading when wet; apices obtuse to broadly acute; lamina unistratose; margins entire, plane; costa subpercurrent, ending 3–6 cells below apex, surface ventral cells elongate, guide cells and two stereid bands present, ventral surface layer enlarged; upper and basal cells strongly differentiated, upper cells oblate, rounded, quadrate, subquadrate to short-rectangular, 4–8 x 4–10 μm, firm-walled, pluripapillose, papillae at times c-shaped, inner basal cells abruptly differentiated, bulging rectangular, lax, smooth, 30–60 x 10–20 μm, alar cells not differentiated. Dioicous. Perichaetia terminal. Male plants small, gemmiform, at base of female plants. Setae smooth, 3–3.5 mm long, red. Capsules ellipsoid, to cylindric, erect, 1.0–1.3 mm long, smooth; exothecial cells short-rectangular, thin-walled; stomata in neck; opercula conic-rostrate, 1 mm long;; annuli well-developed, vesiculose; peristome yellow, basal membrane low, filaments short, straight, spiculose, to 230 μm. Spores 8–10 μm, smooth. Calyptrae cucullate, smooth, 1 mm long.