Riccardia multifida

Reeb, Catherine & Gradstein, Robbert, 2020, A taxonomic revision of Aneuraceae (Marchantiophyta) from eastern Africa with an interactive identification key, Cryptogamie, Bryologie 20 (2), pp. 11-34 : 28-29

Riccardia multifida (L.) Gray (Illustration: Perold 2001b)

Jungermannia multifida L., Species Plantarum 1: 1136 (1753). — Aneura multifida (L.) Dumort., Commentationes Botanicae 112 (1822). — Type: England ( Grolle 1976).

SPECIMEN EXAMINED. — South AFrica. Diepwalle Forest Reserve, 07.X.2000, Perold 4449 (PRE-P581351.0).

DISTRIBUTION. — Riccardia multifida is widespread in temperate regions of the Northern Hemisphere; in addition, the species has been recorded from Brazil (Rio de Janeiro; Gradstein & Costa 2003) and from South Africa where it is known from several localities ( Perold 2001b). The occurrence of R. multifida in South African was confirmed by molecular analysis ( Reeb et al. 2018). The species is not yet known from East Africa and the Indian Ocean Islands, but may be expected there and is therefore included in this treatment.

DESCRIPTION

Monoicous (autoicous).

Thallus

Glossy green when fresh, green to brown in herbarium, fleshy, mostly flat, in compact layers, to 30 mm long, 1-3(-4)-pinnate, with regulary pinnate secondary branches, branches alternate to subopposite, reiterations and flagelliform branches present, stolons absent.

Main axis

Well-defined, in cross section ellipsoid, biconvex(to plano-convex) in the middle, 4-5(-8) cells thick, with a 2-3 cells wide wing, epidermis cells 2-4 × smaller than inner cells.

Primary branches

Up to 5 mm, regularly branched, branching at an angle of c. 45⁰ with the axis, rarely overlapping.

Ultimate branches

Usually narrowly linear, occasionally tongue-shaped to oblong, straight, to 1.6 mm long, 0.5-0.6 mm wide, in cross section plano-convex to biconvex, 3-4 cells thick, winged, wings 3-4 cells wide, narrower than the midrib, branch apex rounded to truncate, margins crenulate by bulging cells.

Mucilage papillae

Apical and in two ventral rows, persistent.

Oil bodies

Absent or rare in epidermis cells, present in inner cells, 1(-2) per cell, spherical to ellipsoidal, light brown, finely granular.

Male branches

Along the axis, solitary to grouped, 600-750 µm long, margins crenate by larger, bulging cells.

Female branches

Laterally inserted, to 450 µm long, margins with mostly straight cilia or scales.

Calyptra

Up to 3 mm long, ornamented by loosely aggregated umbo cells and scattered thick-walled cells.

Gemmae

Not seen.