BFNA Title: Brotherella
Author: W. Schofield
Date: Nov. 13, 2009
Edit Level: R
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden

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XX. BROTHERELLA Loeske ex M. Fleischer, Nova Guinea 12(2):119. 1914  * [For V. F. Brotherus, 1849--1929, Finnish bryologist]

W. B. Schofield†


Plants small to robust, carpet-forming, creeping, glossy yellow to golden or brownish green. Stems 2--20 cm, pinnately to irregularly branched, often somewhat complanate.  Leaves erect-spreading to falcate-secund. Stem leaves ovate to broadly ovate or lanceolate, 0.5--3 mm, ecostate, margins often recurved at basal margin, plane distally, entire except in apex, extending to a long or short acumen, curved; laminal cells smooth, linear-rhomboid in most of lamina, alar cells usually in a distinct group, the most basal row elongate, often inflated, sometimes pigmented with 1--2 rows of shorter supra-alar cells.  Sexual condition dioicous, phyllodioicous, or autoicous. Seta elongate, smooth, red-brown, 1--2 cm. Capsule 0.5--2 mm, inclined or erect, symmetric or asymmetric, exothecial cells not collenchymatous, peristome double, operculum short to long-rostrate.


Species ca. 20 (4 in the flora): North America, Europe, Asia.


Brotherella is a problematic genus in which species are often polymorphic.  Fragmentary material from other genera has been attributed to it, thus the systematics remains in flux.  Even in northwestern North America there remain several specimens difficult to place, partly because material is sterile. These may well represent responses to extreme environments.


SELECTED REFERENCES Tan, B. C. and Y. Jia. 1999. A preliminary revision of Chinese Sematophyllaceae: Brotherella. J. Hattori Bot. Lab. 86: 26--33.  Schofield, W. B. 2006. Brotherella canadensis, sp. nov., from the Pacific coast of North America.  J. Hattori Bot. Lab 100: 355--360.  Ando, H, T. Seki, and W. B. Schofield. 1989. Generic distinctness of Brotherella from Pylaisiadelpha (Musci). Bryologist 92: 209--215.


1.  Plants small, with main leafy shoots 1 mm or less in width; usually irregularly branched; sporangia erect or suberect                                                                    4.  Brotherella roellii


1.  Plants medium-sized to robust, with main leafy shoots 1.5--2 mm wide; branching variable; capsule inclined.


2.  Leafy shoots robust, 4--12 cm, usually forming loose wefts; leaves erect on main shoots, shoot tips penicillate;                                                   2.  Brotherella henonii


2.  Leafy shoots medium-sized, usually 2--4 cm, forming compact, reclining, regularly to irregularly branched mats, leaves mainly falcate-secund, strongly so at tips of main shoots and branches.


3.  Plants markedly complanate, pale green to yellow green; alar cells yellowish or unpigmented                                                           3.  Brotherella recurvans


3.  Plants not complanate; yellow to golden green; alar cells orange or red brown                                                                                                                        1.  Brotherella canadensis



1. Brotherella canadensis W. B. Schofield, J. Hattori Bot. Lab. 100:355.  2006


Plants yellow green to golden, branching in a single horizontal plane, forming wefts or turf. Stems reddish, ca. 4(--10) cm, branching regularly pinnate to irregular; pseudoparaphyllia foliose to filamentous.  Stem leaves ovate-lanceolate, falcate-secund, especially at main stem and branch tips, 1.5--1.7 x ca. 0.8 mm, tapering gradually to a toothed acumen, margins mostly entire; inflated alar cells orange-pigmented, these forming a single row 2--4 cells wide.  Branch leaves similar, but smaller. Sexual condition dioicous(?). Seta elongate, red-brown, smooth, 1.5--2 cm. Capsule inclined, cylindric, slightly asymmetric; operculum long-rostrate, as long as urn.


Mainly peatland and forest margins, but also humid rock faces near streams and water bodies, occasionally epiphytic, especially near tree bases; low to moderate elevations; B.C.; Alaska, Wash.


Brotherella canadensis resembles Hypnum in the field, but the strong gloss and especially the inflated colored alar cells easily separate it.  From B. henonii it is readily distinguished by its smaller plants and strongly falcate-secund leaves, especially near shoot and branch apices. This species is endemic to coastal Pacific North America.


2.   Brotherella henonii  (Duby) M. Fleischer, Nova Guinea 12(2):120.  1914


Hypnum henonii Duby, Flora 60: 93. 1877


Plants robust, yellowish green to yellowish brown, in loose mats. Stems yellowish brown, 4--6(--12) cm, pinnately to irregularly branched, shoot and branch tips penicillate. Stem leaves ovate-lanceolate, erect, 1.7--1.8 x ca. 0.9 mm, tapering abruptly to a long-toothed or occasionally entire acumen. Branch leaves narrower, alar cells with 3--4 swollen, colored, elongate cells.  Sexual condition sterile.


Sporophytes unknown in the area of the flora. Humid shaded sites near streams or cliff bases in forests; 0 m; B.C. (Queen Charlotte Islands); Asia (China, Japan, Korea).


Brotherella henonii suggests an overgrown version of B. canadensis, but is paler green, forms looser wefts, and grows in more humid shaded sites.  The penicillate, rather than falcate-secund shoot and branch tips also easily separate them.  The B.C. populations are few, lack sporophytes, and are slightly different from much of Asiatic B. henonii, but this species is sufficiently variable to include the North American material.


3. Brotherella recurvans (Michaux) M. Fleischer, Nova Guinea 12: 120. 1914


Leskea recurvans Michaux, Fl. Bor.-Amer. 2: 311. 1803; Brotherella delicatula (James ex Sullivant) M. Fleischer; Rhynchostegium delicatulum James ex Sullivant


Plants pale green to yellow green, strongly glossy, subpinnately to irregularly branched, shoots decidedly complanate, compressed to substratum, with tips falcate-secund toward the substratum, strongly so at apices of stems and branches. Stems 2--6 cm; pseudoparaphyllia narrowly to lanceolate filamentous.  Stem leaves ovate, 1--1.5 mm, tapered to a toothed acumen, cells mainly linear to sinuose-linear, alar cells often yellowish, the basalmost row oblong and inflated.  Branch leaves similar. Sexual condition dioicous.  Seta brownish, 1--1.5 cm, smooth. Capsule oblong-cylindric, somewhat asymmetric, inclined; operculum short-rostrate.


Mainly on logs, sometimes on humus, tree trunks, rocks, mainly in forests; low to high elevations; Nfld., N.B., N.S., Ont., P.E.I., Que.; Ala., Conn., Ga., Ill., Ind., Iowa, Me., Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., S.C., Tenn., Vt., Va., W. Va., Wis.


Brotherella recurvans  resembles Pseudotaxiphyllum elegans superficially, but is generally larger, and the swollen alar cells and toothed apiculus readily separate it.  Branches and main shoots bear leaves of similar size and areolation, and branching tends to be irregular.


4. Brotherella roellii (Renauld & Cardot) M. Fleisher, Musci Fl. Buitenzorg 4: 1245.  1023


Rhaphidostegium roellii Renauld & Cardot, Bot Centralbl. 44: 423.  1890


Plants small, pale yellow-green, slender, glossy, reclining. Stems red-brown, little-branched or irregular branched, 0.5--5 cm, branches sometimes flagelliform; pseudoparaphyllia narrowly lanceolate.  Stem leaves ovate-lanceolate, tapering to a narrow, toothed acumen, 0.8--1.2 cm; alar cells with 2--3 inflated red brown cells. Specialized asexual reproduction sometimes by caducous shoots or branches. Sexual condition autoicous. Seta red-brown, smooth, 0.5--1 cm long. Capsule suberect, cylindric, symmetric to somewhat asymmetric, 1--1.5 mm, operculum rostrate.


Mainly on tree trunks and bases, sometimes on organic soil, usually forest margins; low to high elevations; B.C.; Wash.


In the genus, Brotherella roellii is of smallest stature in North America. It is the only autoicous species, thus sporophytes are fairly common.  When sterile, however, it commonly produces readily deciduous flagelliferous shoots or branches.  It appears to be extinct in Washington; no specimens have been collected there for more than 70 years.  In B.C. most collections have been made in secondary forests or on forest edges. This species is endemic to Pacific North America.