Plants small, tufted, green or yellowish. Stems short, erect, simple except for a reduced basal antheridial branch. Leaves larger distally, rosulate, crowded, erect-spreading, reduced in size proximally, oblong-ovate to obovate or spathulate, usually acute or acuminate, sometimes apiculate or piliferous, margins plane or erect, entire or serrulate beyond the middle, costa ending well before the apex to percurrent, distal and median cells mostly medium-sized, quadrate to hexagonal to oblong-hexagonal, rarely short-rhomboid, rather lax and thin-walled, sometimes linear at the margins forming a narrow border, proximal cells becoming oblong-rectangular, differentiated alar cells absent. Sexual condition autoicous or polygamous; antheridial branch basal, perigonial paraphyses clavate; perichaetia apparently absent paraphyses. Seta elongate, erect. Capsule exserted, erect or nearly so, narrowly pyriform to short-pyriform, symmetric, often smooth except at the neck when dry, annulus none, exothecial cells transverse, usually linear-oblong, incrassate with radial walls thicker toward the inner tangential wall than the surface wall; stomata present and formed from single cell; peristome absent to well developed, single or double, inserted proximal to the mouth, teeth papillose-striate, weakly trabeculate to appendiculate or absent these features, segments of the endostome, often evanescent and not seen, rarely more than 1/4 the length of the teeth or absent; operculum nearly plane to conic-convex or domed, cells usually in obliquely radial rows. Calyptra large, long-rostrate, cucullate and inflated. Spores smooth or weakly papillose to tuberculate or bacculate-insulate.

Distribution

North America, Mexico, Central America, South America, Europe, Asia, Africa, Pacific Islands.

Discussion

Species ca. 20 (12 in the flora).

Entosthodon as it is defined here is mainly associated with Mediterranean, shrub-steppe, or desert climates with pronounced wet and dry seasons. The genus is almost certainly under-collected in dry and seasonally dry tropical and warm temperate climates because of the relatively short growth season. Entosthodon is a vexing genus because most species: (1) are short lived; (2) are small and, for the most part, form small, inconspicuous tufts; (3) are usually collected with clinging substrate and careful cleaning is needed; and (4) are frequently in admixture with other small mosses. Fortunately, sporophytes are usually present; otherwise they would probably escape notice. Only E. drummondii is reasonably abundant in herbaria; the other species are represented in collections so uncommonly that their geographic range can only be estimated. It is possible that species are too narrowly drawn in this treatment, but insufficient evidence is available to justify recognizing fewer taxa. Edwin Bartram once remarked (pers. comm.) that he disliked describing new species; he felt defeat when he could not find a proper name but was obliged to provide one or else the taxon would go unrecognized. Entosthodon could have been one of the genera he was talking about.

Excluded Species:

Entosthodon spathulifolius Cardot & Thériot

This entity from St. Paul Island collected by Trelease was considered by A. J. Grout (1928–1940, vol. 2) to be a Tayloria although he had not seen mature capsules.

Selected References

None.

Lower Taxa

Entosthodon attenuatus, Entosthodon bolanderi, Entosthodon californicus, Entosthodon drummondii, Entosthodon fascicularis, Entosthodon kochii, Entosthodon planoconvexus, Entosthodon rubiginosus, Entosthodon rubrisetus, Entosthodon sonorae, Entosthodon tucsonii, Entosthodon wigginsii

Key

1	Leaves broadly acute to rounded-obtuse; capsules short-pyriform, 1-1.4 mm, peristome well developed	> 2
1	Leaves acute to acuminate, capsules pyriform, 1.5 mm or more long, peristome well developed, rudimentary, or absent	> 3
2	Leaves to 2 mm, rounded-obtuse; peristome double, exostome vertically striate throughout and sometimes perforate, endostome a low irregular papillose membrane; spores rounded, 27-36 µm.	Entosthodon drummondii
2	Leaves about 1 mm, broadly acute, often short-apiculate; peristome single, teeth finely papillose throughout to weakly striate-papillose basally, not perforate; spores angled, 17-19 µm.	Entosthodon kochii
3	Spores usually adherent in tetrads at maturity; peristome teeth bright red and often perforate basally, with endostome well developed from a pale basal membrane bearing irregular segments.	Entosthodon wigginsii
3	Spores separate at maturity; peristome various but absent the combination of characteristics given above, sometimes rudimentary or absent	> 4
4	Peristome rudimentary or absent	> 5
4	Peristome well developed	> 7
5	Costa of distal leaves ending below the leaf tip; spores to 40 µm.	Entosthodon tucsonii
5	Costa of the distal leaves ending in or near the tip to excurrent; spores 24-35 µm	> 6
6	Medial exothecial cells oblong; marginal laminal cells undifferentiated, alar regions not auriculate.	Entosthodon rubiginosus
6	Medial exothecial cells irregular to hexagonal, little longer than broad; marginal laminal cells longer and narrower than medial cells, alar regions sometimes forming auricles.	Entosthodon fascicularis
7	Leaves bordered almost to the apex by at least two rows of often orangish, narrow cells	Entosthodon attenuatus
7	Leaves not bordered by rows of orangish, narrow cells	> 8
8	Leaves entire or nearly so	> 9
8	Leaves with distinctly serrate or serrulate margins distally	> 10
9	Leaves with an acute tip that lacks a single long terminal cell, costa strong and ending just before the apex.	Entosthodon californicus
9	Leaves with an acuminate tip usually terminated by a single long cell, costa weak, reaching only 1/2-3/4 the leaf length.	Entosthodon bolanderi
10	Distal leaves acute to short-acuminate, marginal cells somewhat inflated.	Entosthodon sonorae
10	Distal leaves filiform-acuminate or distinctly apiculate with a hair point, marginal cells not differentiated	> 11
11	Operculum planoconvex; leaf apiculus about 250 µm; capsule ovoid-pyriform, yellowish to brownish.	Entosthodon planoconvexus
11	Operculum conic-convex; leaf apiculus about 425 µm; capsule claviform, deep brownish red	Entosthodon rubrisetus