Plagiochila repanda (Schwägr.) Lindenb. var. repanda

Gradstein, S. Robbert & Reeb, Catherine, 2022, The genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar, Cryptogamie, Bryologie 20 (5), pp. 65-106 : 88-90

Plagiochila repanda (Schwägr.) Lindenb. var. repanda

( Fig. 14 )

Jungermannia repanda Schwägr., Historiae Muscorum Hepaticarum Prodromus : 26 (1814). — Plagiochila repanda (Schwägr.) Lindenb. , Species Hepathicarum (fasc. 2-4): 62 (1840). — Type: Mauritius. Unknown collector (lecto-, designated byGrolle [1995], W; isolecto-, S).

Plagiochila ligulata Steph. , Bulletin de l’Herbier Boissier (sér. 2) 4 (4): 347 (1904). — Type: Madagascar ( Grolle 1995).

Plagiochila madagascariensis Gottsche, Abhandlungen des Naturwissenschaftlichen Vereins zu Bremen 7: 344 (1882), nom. inval. (non Steph. 1904). — Type: Madagascar ( Grolle 1995).

Plagiochila nudiuscula Gottsche, Abhandlungen des Naturwissenschaftlichen Vereins zu Bremen 7: 339 (1882).— Type: Madagascar ( Grolle 1995).

Plagiochila rutenbergiana Gottsche, Abhandlungen des Naturwissenschaftlichen Vereins zu Bremen 7: 338 (1882), nom. inval. — Type: Madagascar ( Stephani 1906; Grolle 1995).

SPECIMENS EXAMINED. — Madagascar. Prov. Antananarivo • Angavokely, I.1978, Tixier 11112 ( BR); Ankazobe, Ambohitantely Reserve, IX.1994, Pócs 9444/ AC ( EGR, GOET). — Prov. Antsiranana • Cuvette d’Andape, Mission catholique, VII.1971, Onraedt 70 M5753 ( PC). — Prov. Fianarantsoa • Analabé near Ambositra, VIII.1971, Onraedt 71 M5817 , 71 . M5818 ( BR); Nosiarivo, X.1976, Tixier 9471, det. Vanden Berghen as P. barteri (BR) ; Andringitra Nat. Park , tributary W of Korokoro river , IX.1994, Pócs 9473/ BA ( EGR); Ramomafana Nat. Park , beyond W park boundary, Mt. Namatoana , Pócs & Tuba 04130/AQ ( EGR). — Prov. Toamasina • Masoala Peninsula W coast, slopes E of Ambanizana village, Pócs 9448/ B ( EGR); Andasibe (Perinet), III.1974, Cremers 3142 ( BR); VIII.1977, Tixier 10672 ( BR); Andasibe-Mantadia Nat. Park , III.1990, Pócs et al. 90103/ A, 90103/AE, 90103/ G, 90103/ L ( EGR), 90106/ N ( EGR, GOET); X.1994, Pócs 9485/ P ( EGR) .

DISTRIBUTION AND HABITAT. — East Africa ( Kenya, Tanzania, Malawi) and East African Islands ( Madagascar, La Réunion, Mauritius). In Madagascar growing on bark in humid to subhumid evergreen forests, also on tree ferns, 400-1500 m.

DESCRIPTION (see also Jones 1962; Vanden Berghen 1981) Plants 2-4.5 mm wide, to 10 cm long, slightly and irregularly pinnately branched or unbranched, branches mostly intercalary, occasionally terminal, dorsal stem surface without paraphyllia. Creeping, rhizome-like primary stem present. Mature stem leaves imbricate, obliquely to widely and± horizontally spreading, ovate-rectangular to ovate-triangular, c. 1.5-2.5× longer than wide, usually ampliate, the expanded ventral leaf bases sometimes forming a crest, apex rounded to truncate, entire or with 1-8 small teeth (teeth 1-4 cells long), not bifid, ventral margin usually entire, occasionally with a few irregular teeth, dorsal margin entire; dorsal leaf bases entire, rather shortly and broadly decurrent, inflated, almost concealing the stem, ventral bases shortly to moderately and narrowly decurrent, the linear decurrent portion to 0.2 mm long. Leaf cells subisodiametrical, 15-25 µm wide in midleaf, with small to large, swollen trigones, cells smaller and subquadrate to rectangular along the margin and usually with larger, sometimes confluent trigones, forming a weak border in robust plants; vitta-like area at the base present or absent, cells in the dorsal leaf base not elongate; cuticle smooth; oil bodies not observed.Underleaves absent. Androecia terminal to intercalary, with 3-6 pairs of bracts. Perianth campanulate, base without stalk, mouth with numerous narrowly triangular teeth or cilia. Vegetative reproduction by leaf fragmentation.

NOTES

Plagiochila repanda var. repanda (sect. Vagae) is recognized by the wide-spreading, ovate-rectangular leaves with an ampliate ventral base and leaf margins ± entire or with a few small teeth

(up to 8) at apex. The leafy stems arising from the creeping rhizome-like shoot are long and sparsely branched by intercalary branching (very rarely terminal). Very characteristic are the rather small, subisodiametric leaf cells, 15-25 µm wide in midleaf, with frequently large bulging trigones (but sometimes trigones small). Whden the trigones are large, the leaf is rather opaque. The trigones tend to become larger and confluent at the leaf margin, and the thicker-walled margin cells may form an ill-defined border. The cells at the leaf base are sometimes enlarged, forming a vitta-like area (e.g. in Tixier 9471, det. Vanden Berghen as P. barteri ).

Plagiochila repanda var. perrotana (Steph.) Vanden Bergh.

( Fig. 15 )

Plagiochila perrotana Steph. , Bulletin de l’Herbier Boissier (sér. 2) 4 (6): 586 (1904). — Type: Madagascar. Tamatave, 1896, Bryotheca Levier 347 (lecto-, designated here [ Vanden Berghen 1981 as “ holotype ”], G00065763!); 1897, in silva “Fito”, Perrot s.n., Bryotheca Levier 1214 (syn-, G00068921!).

Plagiochila liliputana sensu Vanden Berghen (1981) , non typus (see below).

SPECIMENS EXAMINED. — Madagascar. Prov. Mahajanga • Seuil de Mandritsara, Jardin Botanique, c. 850 m, Morat 4532a ( BR). — Prov. Toliara • Tôlanaro (“ Fort Dauphin ”), on trees in primary forest, c. 20 m, VI.1971, Onraedt 70 M5561 ( BR 2 specimens as P. liliputana , det. Vanden Berghen). — Prov. Toamasina • Andasibe-Mantadia Nat. Park, III.1990, Pócs et al. 90106/ H, 90106/ J, 90108/X ( EGR); Saharanga river valley, X.1994, Pócs 9484/ P ( EGR); Anosibe, IV.1978, Tixier 11745 ( BR); Analabé, XII.1975, Tixier 7872 ( BR) .

DISTRIBUTION AND HABITAT. — East African Islands ( Comores, Madagascar, La Réunion, Mauritius). In Madagascar on bark and rotten wood in humid to subhumid mid-elevation forests and plantations, 850-1050 m; exceptionally at sea level.

NOTES

Plagiochila repanda var. perrotana is identical to var. repanda except for the mostly bifid leaf apex; in var. repanda the apex is entire or toothed, not bifid. The two teeth at the leaf apex in var. perrotana vary considerably in size and in the specimen from Madritsara (Morat 4532a) they are very long, up to ten cells long.

A collection from lowland elevation (“Fort Dauphin”, Onraedt 70M5561) identified by Vanden Berghen (1981) as P. liliputana , stands out by small plant size (1.5-2 mm wide) and rather distant leaves with ventral bases not or scarcely ampliate. In other respects, the plants are identical to P. repanda var. perrotana . We interprete the specimen as a weak lowland phenotype.

Figures

FIG. 14. ― Plagiochila repanda (Schwägr.) Lindenb. var. repanda: A, habit; B, C, shoots in dorsal view; D, shoot in ventral view, showing ampliate leaf bases; E, leaves; F, leaf apex; G, leaf margin bordered by subquadrate to rectangular cells; H, shoot with terminal androecia; I, J, midleaf cells. From Pócs 90103/AE (EGR). Scale bars: A, 5 mm; B-E, 1 mm; F, 0.5 mm; G-J, 0.05 mm.

FIG. 15. ― Plagiochila repanda var. perrotana (Steph.) Vanden Bergh.: A, leaves; B, portion of leaf. From Pócs 90106H (EGR). Scale bars: A, 1 mm; B, 0.5 mm.