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brittle crisp-moss, fragile tortella moss

tortella moss

Habit Plants coarse, rigid, dark green to yellowish or blackish brown, elongate. Plants dull yellow-green to yellowish brown distally, brown proximally, elongate, not rosulate.
Stem(s)

leaves firm, coarse, rigid, uniform in size and shape along the stem and apex, lowermost leaves mostly without leaf tips, leaves typically fragile only at base of deciduous apical subula, stiffly erect-appressed, incurved (or stem-apical leaves somewhat twisted around the stem when dry);

erect and weakly spreading when moist, narrowly lanceolate to linear, narrowing gradually into the distal region until contracting into a narrower propaguloid region up to 1/2 the distal leaf length; broadly to narrowly concave, keeled toward the apex in nonpropaguloid leaves, 4–6 mm;

base broadly oblong;

margins plane to erect, not to somewhat undulate;

apex narrowly acute, those of nonmodified leaves shallowly channeled to subnaviculate, not cucullate, those of modified leaves long-subulate, fragile, the subula obtusely thickened and multi-stratose distally and often broken off, youngest leaves arising from the stem apex fully propagulose and subulate;

costa short-excurrent as a smooth or weakly denticulate mucro of 1–5 rhomboidal cells, in propaguloid leaves, internal cells in section appearing undifferentiated in the subula;

adaxial surface covered by quadrate to short-rectangular, papillose laminal cells throughout the leaf except in the propaguloid leaf portion where a narrow medial groove is covered by elongate (8:1) smooth cells;

cross section lunate and broad, adaxial epidermal cells may be interrupted in the center, exposing the adaxial stereid layer by about two cells in width, in propaguloid leaves stereid layers appear undifferentiated in the subula;

proximal laminal cells rather abruptly differentiated from distal cells, yellow-hyaline, elongate, firm to laxly thin-walled, smooth;

margin with a narrow line of firm- to thin-walled cells extending a short way up the lamina or to mid-leaf;

distal laminal cells frequently 2-stratose on one or both laminae beside the costa, or equally extending toward the margins in various degrees, and becoming completely 2-stratose and ultimately undifferentiated in the, deciduous leaf tips, rounded-quadrate or hexagonal, (9–)10–12(–13) µm wide, strongly papillose, areolation more or less distinct;

marginal cells in median leaf region undifferentiated, papillose-crenulate, along the distal median margin and into the subula differentiated as one or two rows of smooth, thick-walled, short-rectangular, (4–3:1), epapillose, yellowish cells leading into the subulate region and extending to the apex distinctly visible in at least some leaves, sometimes present only in young leaves on mature stems.

leaves somewhat soft or lax, loosely to more closely foliose, variably gradually somewhat larger and more crowded toward the stem tips or the reverse with the leaves somewhat larger proximally than distally, loosely and irregularly curled to crisped when dry, erect-spreading to spreading when moist, oblong-lanceolate, to lanceolate, sides generally parallel and scarcely tapered from the base, typically strongly keeled-concave or broadly channeled across the leaf adaxially, (1–)1.5–2 mm, not undulate;

base not differentiated or somewhat broader, elliptical;

margins plane to erect, broadly incurved distally, not undulate;

apex typically cucullate, occasionally fistulose, obtuse to acute, occasionally abruptly narrowed and concave-acuminate;

costa short-excurrent by 1–3 cells, cells of the adaxial surface cells entirely smooth and narrowly elongated, 8:1, throughout, adaxial epidermis absent, without 2-stratose areas at juncture with lamina; occasionally abaxial surface roughened by projecting distal cell ends, these more dense at the leaf apex;

proximal laminal cells abruptly differentiated from distal cells, pale yellow, transparent, elongate, laxly very thin-walled and fragile, smooth;

marginal cells undifferentiated, sharply crenulate-papillose;

distal laminal cells densely and sharply papillose, quadrate, 10–12 µm wide.

Seta

1.5–2 cm, occasionally two per perichaetium.

1.5–2.7 cm.

Sexual condition

dioicous;

perigonia not seen;

perichaetial leaves setaceous, fragile, with propaguloid modifications as in stem leaves.

dioicous;

perigonia not seen;

perichaetial leaves of fertilized archegonia conspicuously differentiated, elongate, 2–5.5 mm, erect from a broad, long and hyaline sheathing sometimes inflated base, when dry, the erect leaves distinct from the crispate stem leaves.

Capsule

1.8–3 mm;

annulus none or of 1–2 rows of weakly vesiculose cells, operculum ca. 1.5 mm;

peristome teeth long, spirally wound, twisted 1–3 times.

1.5–2 mm, annular cells not vesiculose;

operculum 1–2 mm;

peristome teeth long, to 0.7 mm, spirally wound more than once.

Specialized

asexual reproduction by deciduous, subulate, rigid, smooth-sided, distally thickened apices of all leaves.

asexual reproduction none.

Tortella fragilis

Tortella inclinata

Habitat Seldom fruiting, capsules mature summer (Jun). Substrates probably dessicated some of the year, acid or calcareous rock, seepage, crevices and ledges of cliffs in maritime situations, dry prairies, logs or peaty humus in springs, fens, Thuja swamps, open sands of lake shores, tundra, alpine and willow bogs, frost boils, margins of solifluction lobes, snow patch margins
Elevation low to high elevations (0-3600 m) (low to high elevations (0-11800 ft))
Distribution
from FNA
AK; CO; IA; MI; MN; MT; NC; ND; NJ; NV; NY; OR; SD; TN; VT; WA; WY; AB; BC; LB; MB; NB; NS; NT; NU; ON; QC; YT; Atlantic Islands (Iceland); Australasia; Pacific Islands (New Zealand); Greenland; Africa; Asia; Europe; Antarctica
[WildflowerSearch map]
North America; South America; Europe; Asia; Africa; Australia
Discussion

The long, subulate, rigid, usually fragile leaves with propaguloid tips that are not or only slightly contorted when dry are distinctive of Tortella fragilis. In ambiguous cases, the 2-stratose cross section of the distal leaves is diagnostic, but usually all that is necessary for identification is to demonstrate the smooth, elongate, thicker-walled cells along the leaf margin near the apex. The leaves may be stiff and merely arcuate in some plants, in others variously to strongly contorted-circinate, but not crisped. Such plants may be difficult to distinguish from Tortella tortuosa var. fragilifolia, which, however, has a fragile leaf lamina in addition to fragile leaf apices

Quadrate, papillose epidermal cells across the adaxial portion of the costa occur throughout the leaf of Tortella fragilis except in the proximal cell region and in the propaguloid-setaceous part of the leaf where the costa is often exposed in a continuous groove of elongate cells. This character is useful in distinguishing the species from T. rigens, which has a continuous band of smooth, elongate cells on the adaxial surface of the costa throughout the length of the leaf.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Varieties 3 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stems short, to 1 cm, not to few-branched, tomentum usually conspicuous; leaf cross section with adaxial and abaxial superficial walls the same width as the cross-walls; papillae not elevated, leaf cells 10-12 µm, stems yellow or green, rather pale, brown proximally, yellow in KOH; leaves irregularly twisted and incurved when dry; majority of leaf apices obtuse, strongly cucullate, mucro of 1-3 cells; low sandy alluvium of beaches and streams
var. inclinata
1. Stems tall, to 2 cm, many-branched, tomentum hidden in leaf axils; leaf cross section with thick abaxial and adaxial superficial walls, but thin cross-walls; papillae appearing pedestaled on thick walls, leaf cells 7-10 µm; stems dull and often strongly orange-green, orange, or dull green distally and brownish black proximally, orange in KOH; leaves when dry somewhat uniformly twisted on the stem (funaliform), erect proximally; leaf apices cucullate, acute, to narrowly acuminate, mucro of 5-7 cells; rock crevices, hillsides and upland alluvium
var. densa
Source FNA vol. 27, p. 507. FNA vol. 27, p. 508.
Parent taxa Pottiaceae > subfam. Trichostomoideae > Tortella Pottiaceae > subfam. Trichostomoideae > Tortella
Sibling taxa
T. alpicola, T. flavovirens, T. humilis, T. inclinata, T. rigens, T. tortuosa
T. alpicola, T. flavovirens, T. fragilis, T. humilis, T. rigens, T. tortuosa
Subordinate taxa
T. inclinata var. densa, T. inclinata var. inclinata
Synonyms Didymodon fragilis Tortula inclinata, Barbula inclinata
Name authority (Hooker & Wilson) Limpricht: Laubm. Deutschl. 1: 606. (1888) (R. Hedwig) Limpricht: Laubm. Deutschl. 1: 602. (1888)
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