Riccardia fastigiata (Lehm.) Trevis.

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 : 21-22

publication ID	https://doi.org/ 10.5252/cryptogamie-bryologie2020v41a2
persistent identifier	https://treatment.plazi.org/id/03EF87AA-652E-FFC6-CAD0-E43AFE94F801
treatment provided by	Felipe
scientific name	Riccardia fastigiata (Lehm.) Trevis.
status

Treatment

Riccardia fastigiata (Lehm.) Trevis. View in CoL

( Fig. 2 View FIG M-R)

Jungermannia fastigiata Lehm. , Linnaea View in CoL 4: 370 (1829). — Aneura fastigiata (Lehm.) Lehm. & Lindenb. View in CoL , Synopsis Hepaticarum 500 (1846). — Type: Cape Town, „Montis Teufelsberg et in vertice montis Tafelberg“, Ecklon s.n. (lecto-, S-B104928!; isolecto-, G[G0067556]!).

? Aneura caespitans Steph. View in CoL , Bulletin de la Société Royal de Botanique de Belgique 30: 194 (1891) — Type: Réunion, Rodriguez s.n., ex hb. Renauld (holo-, BM[BM001167936]!). syn. nov.

FURTHER SPECIMENS EXAMINED. — Réunion. Cirque de Salazie, plaine des Merles, 21°02’50”S, 55°28’08”E, 1800 m, 24.VIII.1994, Vojko 9422AP*, 9422V* (EGR); Forêt de Belouve, plateau des Cochons, 21°02’00”S, 55°33’00”E, 1430 m, 02.VII.1996, Orban 9615CB* (EGR, PC0146833); Piton de la Fournaise. 21°18’00”S 55°42’07”E. 1390-2100 m. 30.VI.1996. Pócs 9613CD* (EGR).

South AFrica. Pietermaritzburg, 914 m, XII.1914, Sim 7536, 7538 ( PRE); Knysna, 01.IV.1929, Bottomley 3671 ( PRE); eastern slope of Table Mountain, 300 m, 19.III.1995, Arts 3318CD ( PRE).

DISTRIBUTION. — South Africa, Réunion.

HABITAT. — Among Sphagnum and on rocks in streams, between 300 and 2100 m.

DESCRIPTION

Monoicous (Dioicous).

Thallus

Gray green, olive to deep green when fresh, becoming darker colored in herbarium, flaccid, strap-shaped, loosely or not attached to the substrate, to 25 mm long, 1-3-pinnate, not palmate, branches alternate, flagelliform branches sometimes present, stolons not seen.

Main axis

Well-defined, to 1 mm wide, in cross section plano-convex to concave-convex, usually with mycorrhiza-like fungi in the ventral part, 4-6 cells thick, margin rounded to acute, with a translucent band of protruding cells but not clearly winged, epidermis cells c. 2-3× smaller than inner cells to equal in size, regularly quadrate, radial walls of the epidermis cells often thickened (in material from Réunion).

Ultimate branches

Tongue-shaped to oblong, mostly 1-2(-4) mm long and 200- 400(-500) µm wide, at an angle of 60-80° with the axis, cross section similar to axis, margins with protruding cells but not clearly winged, branch apex often broadened, rounded or cucullate, not dissected.

Mucilage papillae

In two rows, clavate.

Oil bodies

Not seen.

Male branches

Short, straight or reflexed, often shortly stalked, up to 900 µm, max. of 7-8 antheridial pairs, regularly bordered by a plane or undulate, 2-3 cells wide wing.

Female branches

Mostly solitary, laterally inserted, present along the main axis and along primary branches, sessile or shortly stalked, recurved when immature, 300-800 µm long, with wing-like scales, the scales 2-4 cells wide; archegonia in up to five pairs.

Calyptra

With an umbo of aggregated cells and pachydermal scattered cells.

Gemmae

Occasionally present, 2-celled.

COMMENTS

Riccardia fastigiata resembles R. chamedryfolia but the latter species is autoicous and has clearly winged branches. A noteworthy feature of the specimens of R. fastigiata from Réunion are the thickened radial walls of the epidermis cells. In the material from South Africa, including the type, epidermal thickenings are usually lacking. As the plants from the two regions are identical in all other respects, we treat them as conspecific. Fresh collections are needed to verify this (DNA of the South African plants could not be amplified).

Aneura caespitans Steph. is probably a synonym of Riccardia fastigiata . The type material ( Réunion, leg. Rodriguez) is sterile and poorly developed. Reeb & Bardat (2014) did not see the type (it is lacking in G) and treated A. caespitans as a dubious name. They noted that the description of the species in Species Hepaticarum (Stephani, 1898-1924) is heterogeneous and includes characters of two different species, including the type and a specimen from Cameroon (Dusén 251) not mentioned in the protologue. The confusion was worsened by Stephani’s illustration of A. caespitans in Icones Ineditae (Stephani 1985), which was based on the specimen from Cameroon and not on the type. We have now been able to examine both specimens (kept in BM) and found that the type belongs probably to R. fastigiata , as mentioned, whereas the plant from Cameroon is R. saccatiflora . Already E.W. Jones (in sched.) noted that the type of A. caespitans and the specimen from Cameroon are different taxa. Since no duplicates of the type are present in G or other herbaria, the collection in BM may be considered the holotype.