Racomitrium crispipilum (Taylor) A.Jaeger

  • Authority

    Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part One: Sphagnales to Bryales. Mem. New York Bot. Gard. 69 (1): 1-452.

  • Family


  • Scientific Name

    Racomitrium crispipilum (Taylor) A.Jaeger

  • Description

    Species Description - Plants yellow-brown, usually hoary. Stems with an abundance of short, tuftlike branches. Leaves erect when dry, erect-spreading to spreading when moist, about 3-3.5 mm long (including hair points), lance-acuminate and ending in a long, crisped, smooth, hyaline hair point (sometimes considerably reduced); margins unistratose, recurved on 1 or both sides; costa shortly excurrent into the hair point; cells linear and nodose throughout, smooth; basal marginal cells short in 1 to 5 rows. Setae about 7-10 mm long; capsules about 2.5 mm long, cylindric. Spores 9-12 µm, smooth.

  • Discussion

    Fig. 307

    R. crispipilum (Tayl.) Jaeg., Ber. Thatigk. St. Gallischen Naturwiss. Ges. 1872-73:96. 1874.

    Trichostomum crispipilumTayl., London J. Bot. 5: 47. 1846.

    Grimmia cylindrica C. Müll., Syn. Muse. Frond. 1: 805. 1849.

    G. conterminaC. Müll., Syn. Muse. Frond. 2: 655. 1851.

    Racomitrium cylindricum (C. Müll.) Besch., Mem. Soc. Sci. Nat. Cherbourg 16: 184. 1872.

    R. conterminum (C. Müll.) Jaeg., Ber. Thatigk. St. Gallischen Naturwiss. Ges. 1872-73: 99.1874.

    R. fragile Ren. & Card., Rev. Bryol. 36: 106. 1909.

    The leaves typically end in long, crisped hair points that are flat and entire. T h e development of hair points varies considerably but probably not as m u c h as Clifford (1955) and other authors have allowed. Contrary to Chfford's opinion, Racomitrium crispipilum cannot be included in synonymy with the wide-ranging austral R. crispulum (Hook. f. & Wils.) Hook. f. & Wils. Lawton (1973) has shown significant differences, including bistratose leaf margins in R. crispulum var. crispulum, although some similarity in respect to the unistratose condition can be seen in R. crispulum var. tasmanicum (Hampe) Lawt. (See also Frisvoll, 1988.)

    Racomitrium heterostichum (Hedw.) Brid., of wide distribution in the Northern Hemisphere, has leaves with shorter, terete hair points (commonly lacking) and shorter upper cells. In many Mexican collections ofR. crispipilum the hair points are reduced or even lacking, and in the muticous forms the cells near the apex (and especially at the margins) may be relatively short. The hair points, even when reduced, usually seem flat and crisped. There seems to be no clear-cut reason to refer such material, muticous or otherwise, to R. heterostichum or its var. microcarpon (Hedw.) Boul.

    Some collections from the high volcanic peaks of central Mexico (in the Distrito Federal and the state of Mexico) were referred by Frisvoll to Racomitrium subsecundum (Hook. & Grev. ex Hook.) Mitt. H e placed in the synonymy of that species R. cylindricum and R. fragile. The only tangible difference that he gave seems to be in the development of alar cells, enlarged or inflated in 2-5 rows in R. subsecundum, subquadrate in a single marginal row in R. crispipilum. I have not seen any marked differences in this respect.

  • Distribution

    On rocks at 3200-4300 m alt.; Distrito Federal, Hidalgo, Mexico, Michoacan, Oaxaca, Puebla, Tlaxcala, Veracruz.—Mexico; Guatemala, Costa Rica, and Panama; northern South America; Dominican Republic

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