BFNA Title: Blasiaceae
Date: Jan 22, 2020
Edit Level: S
Version: 1

Bryophyte Flora of North America, Provisional Publication
Missouri Botanical Garden
BFNA Web site: http://www.mobot.org/plantscience/BFNA/bfnamenu.htm

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XX. BLASIACEAE Klinggräff

Karen S. Renzaglia

Plants thallose, terrestrial, bright to dark green, often blotched with anthocyanins (red to purple). Thallus midrib broad and flattened to narrow and rib-like, wing divided into inconspicuous to distinct regular, leaf-like lobes that are unistratose except at extreme base, dichotomous branching, without strong internal cell differentiation, well-developed ventral apical scales, in two rows on the midrib, that become inconspicuous farther from the apex, and with ventral superficial auricles containing Nostoc colonies. Sexual condition dioicous, male plants often smaller than female, gametangia dorsal on main thallus segments, antheridia individually sunken in dorsal pits. Capsule ellipsoidal to ovoid, protected by a fragile calyptra and well-developed pouch-like involucre, four-valved, fixed elaters few, basal, capsule wall 2-stratose, seta massive and elongate. Spores unicellular to multicellular when shed, endosporic, spore walls thin and delicate,

Genera 2 (1 in the flora): nearly worldwide.

The thalli of Blasiaceae have wedge-shaped apical cells, faint central strands, oil bodies present or absent, asexual reproduction through stalked spherical gemmae in dorsal receptacles, and complex stellate gemmae (Blasia only). The archegonia are superficial, in groups and often covered by an involucre. Spores are generated through monoplastidic meiosis, with a single large plastid in the early stage of spore development. The sporophyte foot is bulbous to conical, with several layers of transfer cells on both sides of the placenta. Sporeling and gemmae development involves a quadrant system. There are two genera, Blasia, which is circumboreal, and Cavicularia Stephani restricted to Japan.

 SELECTED REFERENCES  Duckett, J. G. and K. S. Renzaglia. 1993. The reproductive biology of the liverwort Blasia pusilla L. J. Bryol. 17: 541--552.   Renzaglia, K. S. 1982. A comparative developmental investigation of the gametophyte generation in the Metzgeriales (Hepatophyta). Bryophyt. Biblioth. 24: 1--253. Vaduz.   Schuster, R. M., 1992. The Hepaticae and Anthocerotae of North America east of the Hundredth Meridian, Volume V. Chicago.

1. BLASIA L.. Sp. Pl. 2: 1138. 1753 * [For Blaso Biagi, a monk, companion of Tournefort when botanizing in Italy]

Thallus with distinct lateral lobes, succubously arranged, 2--5 faint central strands, oil bodies absent, scales ventral, curving over the apex, and extend in two rows on thallus. Asexual reproduction by two types of dorsal gemmae, long-lived ellipsoidal gemmae containing abundant lipid and protein reserves, produced in dorsal flask-shaped receptacles with long necks, and stellate gemmae each equipped with two Nostoc auricles and two scales. Sexual condition dioicous, male plants smaller, antheridia dorsal in two rows, secondarily sunken in individual chambers. Capsule oval, basal collar of four to six cell layers of sterile tissue, gametophyte dies as sporophyte overwinters. Spores unicellular when shed. Foot variable from bulbous to elongated, several layers of transfer cells on both sides of the placenta.

Species 1: North America, West Indies, Central America, South America, Europe, Asia, Africa, Atlantic Islands, Australia.

1. Blasia pusilla L., Sp. Pl. 2: 1138. 1753

Male plants 1--2 mm in width. Female plants 3--5 mm broad. Spores 30--40 μm when shed, elaters average 25 μm in length, tapered, occasionally branched, 2-spiraled.

Temporary sites, on loose silt, clay or loam soil of roadsides and stream banks; low to high elevations; Greenland; Alta., B.C., Man., N.B., Nfld. and Labrador, N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Mass., Mich., Minn., Miss., Mo., Mont., Nev., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., Tenn., Vt., Va., Wash., W.Va., Wis.; West Indies; Central America; South America; Eurasia, Asia; Africa (including Madagascar); Atlantic Islands; Australia.

Blasia pusilla grows commonly with hornworts, but the species can be distinguished by dorsal stellate gemmae and flask-shaped receptacles, dichotomous branching, and distinct midrib and thallus lobes. The thallus of Anthoceros and Phaeoceros are more orbicular, and lack a midrib.