Orthotrichum pariatum Mitt.

  • Authority

    Buck, William R. 1987. Bryostephane Steereana: A Collection of Bryological Papers Presented to William Campbell Steere On The Occasion of His 80th Birthday. Mem. New York Bot. Gard. 45: 1-749.

  • Family

    Orthotrichaceae

  • Scientific Name

    Orthotrichum pariatum Mitt.

  • Description

    Species Description - Plants loosely or densely tufted, usually ca. 2.5 cm tall, rarely to 4.5 cm, olive-green or yellowish green above, sometimes with brown apices, brown below; rhizoids developed at bases of stems only. Leaves spreading when moist, erect to open and somewhat flexuose when dry, from ovate bases acuminate, sometimes abmptly narrowed into apiculi, 2.4-3.6 x (0.4-)0.6-0.8 mm; costa ending some distance below the apex; margins entire, revolute almost the entire length, sometimes undulate near apex; basal leaf cells 30-85 x 8-14 µm, elongate, rectangular with thick, sometimes nodose and porose walls; alar cells slightly diflferentiated, forming small auricles; upper leaf ceUs 8-14(-17) x 6-10(-14) µm, rounded, irregular, isodiametric to elongate, slightly thick-walled, with two single or branched papillae per cell. Goniautoicous. Perichaetial leaves not diflferentiated. Capsules exserted, cylindric, with eight deep furrows when dry, but not constricted below the mouth, exothecial cells diflferentiated into eight bands with several rows of small cells below the mouth; stomata superficial, in central and lower parts of capsules; peristome double, preperistome not observed; exostome teeth eight, reflexed when dry, pale orange, with a dense cover of tall, branched papillae obscuring the borders between the old cells; endostome segments eight, lance-olate, almost or as tall as the exostome, mostly of two rows of cells, with an open pattem of large, branched papillae. Spores globose, 22-28(-33) µm, finely and evenly papillose, brown, often with green interior. Calyptrae large, conic-oblong, only slightly plicate, pale yellowish or brown with darker apices and many to few hairs reaching to or just over the top.

  • Discussion

    Type: ECUADOR. Titaicun, Spruce 130 (lectotype ny).

    Orthotrichum exsertisetum C. Müll, Nouvo Giom. Bot. Ital. n. ser. 4: 122. 1897. Type: BOLIVIA. Cochabamba: Prope Choquecamata, Jun 1889, Germain s.n. (Bryotheca E. Levier; lectotype h; isotypes JE, M, NY).

    Earlier reports: Williams (1903, 1927), Bartram (1934; specimen not seen), Herzog (1916a, 1916b), Theriot (1936; specimen not seen). Williams (1903) and Herzog's reports refer to O. exsertisetum. Williams' collection 1839 belongs to O. pariatum; Herzog's number 3599 to O. elongatum, 2996 and 3608 to O. pariatum.

    Variation: Orthotrichum pariatum varies in growth form from slender single plants among other bryophytes to pure dense tufts. The capsules are only very rarely smooth. Of the specimens seen only two were almost without any striae or furrows.

    Diflferentiation: Orthotrichum pariatum can be mistaken for O. pycnophyllum and O. elongatum. Orthotrichum pycnophyllum, however, has 16 exostome teeth and endostome segments; O. elongatum has smooth capsules, elongate upper leaf cells, and longer, more strongly undulate leaves. For differences from O. psycrophilum see the latter.

    Illustrations: Figures 73-83.

    Notes: Type collections studied of O. exsertisetum were fairly small, consisting of single or few plants. The protologue states the capsules are smooth or only furrowed below the mouth when dry. Some, however, are furrowed half-way down. The plants clearly belong to O. pariatum.

    Dixon (1924) published a paper on some mosses from high altitudes. In this he mentioned two Orthotrichum collections from the mountain Chimborazo in Ecuador. He considered the plants to be O. apiculatum Mitt, which he regarded as synonymous with O. wagneri Lor. The latter is here considered conspecific with O. pycnophyllum, whereas the plants cited by Dixon are referred to O. pariatum. They have the longer acuminate leaves characteristic for this species, with the apices sometimes abruptly narrowed into short apiculi. They are not, as stated by Dixon, formed by the excurrent costae but consist of laminal cells. None of the leaves sectioned had bistratose margins. Unfortunately, none of the collections had mature sporophytes.

  • Distribution

    Distribution: Argentina, Bolivia, Colombia, Costa Rica, Ecuador, Peru, Venezuela.

    Argentina South America| Bolivia South America| Colombia South America| Costa Rica South America| Ecuador South America| Peru South America| Venezuela South America|