BFNA Title: Groutiella
Author: D. H. Vitt
Date: August 14, 2003
Edit Level: R Brum + C2
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
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Groutiella - Orthotrichaceae


3.  Groutiella H. A. Crum & Steere, Bryologist 53: 145.  1950 * [For Abel Joel Grout, who was especially interested in the Orthotrichaceae]

Dale H. Vitt

Craspedophyllum Grout; Micromitrium Bescherelle


Plants dull, in tomentose mats usually on trees.  Stems creeping, with numerous, erect usually simple branches up to 2 cm high.  Branch leaves contorted and often spirally twisted around stem, ± undulate when dry, lanceolate to lingulate, rounded-obtuse and mucronate to gradually narrowed to a linear, fragile subula, lamina sometimes rugose; margins entire or denticulate, plane, or broadly reflexed; costa percurrent or excurrent; distal laminal cells small, rounded-hexagonal, bulging; marginal laminal cells basally elongate-linear, extending distally 1/4 or more of the leaf or sometimes nearly to apex as a border, cells near insertion inflated and yellowish.  Sexual condition dioicous and perigonia terminal, or pseudautoicous and dwarf male plants on leaves and tomentum.  Seta to 11 mm.  Capsule fully exserted; oblong-ovate to cylindric, usually smooth or obscurely plicate when old; stomates superficial; peristome rudimentary, usually consisting of low, multistratose, papillose membrane; operculum ± convex-conic, with long rostrum.  Calyptra mitrate, plicate, smooth, naked, covering less that 1/2 of capsule, conic, ± lacerate, or divided into numerous lobes.  Spores isomorphic or anisomorphic.


Species ca. 20 (2 species in the flora); pantropical; Mexico, North America, Central America, South America, Asia, Africa, Australia.



1.  Distal leaves widest distal to midleaf, ending in long, linear, fragile subula . . . 1. Groutiella tomentosa

1.  Distal leaves widest at or distal to midleaf, apex rounded-obtuse, mucronate, not fragile . . . 2. Groutiella tumidula



1.  Groutiella tomentosa (Hornschuch) Wijk & Margadant, Taxon 9: 51.  1960

Macromitrium tomentosum Hornschuch in Martius, Fl. Bras. 1(2): 21. 1840


Plants forming greenish mats.  Branch leaves ± undulate, spirally-twisted or contorted, with distal portions erect when dry, distal leaves erect-spreading to spreading, proximal leaves spreading to wide-spreading and ± undulate when moist, lanceolate-oblong to ovate-lanceolate, 1.5--3 mm, narrowed to long, linear, rigid, fragile subula, proximal leaves often sharply acute; margins entire distally, denticulate by means of projecting ends of cells proximally; costa prominent, vanishing in subula, or in proximal leaves often ending near apex; distal laminal cells 3--6 µm, irregularly-rounded to elliptic-hexagonal, bulging.  Sexual condition dioicous, male plants similar to female ones.  Seta 5--11 mm.  Capsule oblong-cylindric to short-cylindric, 2.2--3.5 mm.  Spores 22--32 µm, isomorphic.


Trees and rocks in tropical and subtropical forests; low elevations; Fla.; Mexico (San Luis Potosí, Tamaulipas); West Indies; Central America; South America; Asia.


This species has leaves narrowed to a rigid, long subula that is often fragile.



2.  Groutiella tumidula (Mitten) Vitt, Bryologist 82: 9.  1979

Macromitrium tumidulum Mitten, J. Linn. Soc. Bot. 12: 201.  1869


Plants forming reddish-brown mats.  Branch leaves ± contorted, spirally twisted around branches, with tips incurved when dry, oblong to oblong-lingulate, 1--1.8 mm, rounded to obtuse, ending in a short mucro, longitudinally plicate; margins entire; costa prominent, ending just below or in the short mucro; distal leaf cells 6--9 µm wide, rounded-hexagonal, bulging.  Sexual condition pseudautoicous, dwarf males on leaves and tomentum.  Seta 3--5 mm.  Capsule oblong to oblong-ovate, 1--1.5 mm.  Spores 15--22 µm wide, anisomorphic.


Rocks and trees; usually on horizontal branches 1--3 m high; low elevations; Fla.; Mexico; West Indies; Central America; South America.


This species is distinguished by non-rugose leaves, which have a length-width ratio of less than 5:1 and by erect branches less than 5 mm high. The apex of the leaf is mucronate and never strongly apiculate and the leaves are broadly longitudinally plicate when moist.