Ephemeraceae

Diagnostic features of Ephemerum cohaerens, from Bryan (2007).

Belongs within: Bryophyta.

The Ephemeraceae are a family of minute, morphologically reduced mosses, consisting of persistent protonemata from which the ephemeral plants grow when conditions permit. They are usually found in habitats that are marginal for other mosses, such as sunny patches (Bryan 2007). The capsule may be cleistocarpous as in species of Ephemerum or open by a dehiscence line as in Nanomitriopsis longifolia.

Characters (from Bryan 2007): Plants leafy ephemerals, less than 3 mm, solitary, scattered, or gregarious on sparse or abundant protonemata with upright, aerial, determinate branches; green, pale-yellow, or brown. Stem virtually absent or to 1 mm (to 3.7 mm in Micromitrium synoicum), rhizoids absent or few. Leaves rarely more than 12; proximal leaves small, broadly triangular to ovate, ecostate, apex acuminate; distal leaves becoming larger, linear, lanceolate, or ligulate, with or without shoulders, margins distal to the middle entire, serrulate, serrate, or spinose, apex acuminate; costate or ecostate; laminal cells lax and transparent, long-rhomboidal to rectangular, in some species becoming denser distally, smooth, papillose by projecting distal ends, or spinose. Specialized asexual reproduction by fragments and rarely by thick-walled elongate, swollen protonematal segments, commonly brown, and persisting on or in the soil. Sexual condition autoicous, dioicous, or synoicous. Perigonia arising from protonemata, from rhizoids, or just proximal to the perichaetium; small, bud-like with ecostate leaves of lax areolation, broadly triangular to broadly ovate. Perichaetium consisting of 1-3 most distal leaves on the stem, typically the largest and best developed. Vaginula conspicuous. Sporophytes 1-3 per perichaetium with immersed to emerging capsules. Seta virtually absent or very short. Capsule globose or ovoid, without or with an apiculus, cleistocarpous or opening along an indistinct or distinct ring of cells near the equator; exothecium of 1-2 layers of lax and thin-walled cells; stomates absent or superficial with two guard cells. Calyptra persistent, mitrate, and minute, or fugacious, mitrate or cucullate, and irregularly lobed or torn at the base, covering up to 2/3 of the capsule. Spores appearing reniform, globose, or variously angled, 20-120 µm, ranging from barely papillose to coarsely warty, the elaboration often correlating with degree of maturity, usually bearing small remnants of a hyaline membrane, orange, red, brown, or black.

<==Ephemeraceae
    |--Nanomitriopsis Cardot 1909 SK02
    |    `--N. longifolia Cardot 1909 SK02
    `--Ephemerum Hampe 1837 SK02
         |--E. capense Müll.Hal. 1888 SK02
         |--E. cohaerens FHH01 [=Phascum cohaerens D24]
         |--E. cristatum (Hooker & Wilson) Müll.Hal. 1847 (see below for synonymy) SK02
         |--E. fimbriatum Müll.Hal. 1872 SK02
         |--E. intermedium D24
         |--E. furcatum Stone 1996 SK02
         |--E. recurvifolium (Dicks.) Boulay 1872 SK02 [=Ephemerella recurvifolia D24, Phascum recurvifolium D24]
         |--E. rehmannii (Müll.Hal.) Broth. 1924 SK02
         |--E. serratum [=Phascum serratum] D24
         |    |--E. s. var. serratum D24
         |    `--E. s. var. angustifolium [incl. E. minutissimum] D24
         |--E. sessile [=Phascum sessile; incl. E. stenophyllum] D24
         |    |--E. s. var. sessile D24
         |    `--E. s. var. brevifolium D24
         `--E. stellatum D24

Ephemerum cristatum (Hooker & Wilson) Müll.Hal. 1847 [=Phascum cristatum; incl. E. grosseciliatum Müll.Hal. 1898] SK02

*Type species of generic name indicated

REFERENCES

Bryan, V. S. 2007. Ephemeraceae. In: Flora of North America Editorial Committee (eds) Flora of North America North of Mexico, vol. 27, pp. 646-653. New York and Oxford.

[D24] Dixon, H. N. 1924. The Student's Handbook of British Mosses 3rd ed. V. V. Sumfield: Eastbourne.

[FHH01] Frey, W., M. Hofmann & H. H. Hilger. 2001. The gametophyte-sporophyte junction: unequivocal hints for two evolutionary lines of archegoniate land plants. Flora 196: 431–445.

[SK02] Streimann, H., & N. Klazenga. 2002. Catalogue of Australian Mosses. Flora of Australia Supplementary Series 17. Australian Biological Resources Study: Canberra.