Plagiochila rodriguezii Steph.

Gradstein, S. Robbert & Reeb, Catherine, 2022, The genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar, Cryptogamie, Bryologie 20 (5), pp. 65-106 : 90-92

Plagiochila rodriguezii Steph.

( Fig. 16 )

Plagiochila rodriguezii Steph. , Botanical Gazette 15: 290 (1890). — Type: France. La Réunion, 1889, Rodriguez 140 (lecto-, designated here, G00045515!; isolecto-, PC0102937!, PC0102938!). Plagiochila liliputana Herzog, Botaniska Notiser 101: 232 (1947). — Type: Comores ( Grolle 1995).

ADDITIONAL SPECIMENS EXAMINED. — Madagascar. Prov. Antsiranana • Marojejy Nat. Park, III.1990, Pócs et al. 90115/ F ( EGR). — Prov. Fianarantsoa • near Ambositra, I.1970, Onraedt 70 M41 , 70 M361 ( BR); Andringitra Nat. Park, tributary W of Korokoro river, IX.1994, Pócs 9473/ AV ( EGR). — Prov. Toamasina • near Moramanga , I.1970, Onraedt 70 M2034 ( BR) .

DISTRIBUTION AND HABITAT. — East Africa ( Tanzania), East African Islands ( Comores, Madagascar, La Réunion). In Madagascar found on bark in humid evergreen forests at 1000-1800 m.

DESCRIPTION (see also Vanden Berghen 1981)

Plants 2.5-3 mm wide, to 5 cm long, rather rigid, irregularly pinnate, becoming dichotomous in younger parts, branches mostly terminal, few intercalary branches. Creeping, rhizome -like shoot present, long. Stem surface without paraphyllia. Mature stem leaves imbricate and ventrad, obliquely spreading, asymmetrically ovate-triangular, c. 1.5× longer than wide, ± ampliate, margins unbordered, ventral margin arched and deeply undulate-crispate from base to near apex, undulations entire or with 1-several sharp, to 10 cells long triangular teeth, the teeth up to 20 per leaf, dorsal margin almost straight, narrowly recurved and entire or with 1-2 short teeth; dorsal bases longly broadly decurrent, partly to entirely covering the stem, ventral bases shortly and very narrowly decurrent, the decurrent part entire. Leaf cells subrectangular, 10-20 µm wide in midleaf, trigones small to large and confluent, cell-lumina rounded to flexuose-angular; leaf base with a short vitta-like area; cuticle smooth; oil bodies not observed. Underleaves absent. Androecia terminal to intercalary, of 4-10 pairs of bracts. Perianth without stalk, perianth mouth densely toothed by shortly triangular teeth. Vegetative reproduction not observed.

NOTES

Plagiochila rodriguezii (sect. Vagae) is readily recognized by the rigid, irregularly (bi)pinnate to dichtomous plants with terminal and intercalary branches, ventrad leaves with strongly undulate-crispate ventral margins without or with several (to 15) long and sharp teeth, small leaf cells (10-20 µm wide in midleaf), and absence of underleaves. In the type material the undulate ventral leaf margins are subentire but in the collections made by Pócs (EGR) they are strongly toothed.

In the branching type and undulate-crispate ventral leaf margins, P. rodriguezii is similar to P. squamulosa and P. corrugata but the ventral leaf bases in the latter two species are broadly and longly decurrent and ciliate-laciniate, underleaves are present and the leaf cells are slightly larger. Moreover, P. squamulosa has paraphyllia.

Plagiochila rodriguezii shares undulate ventral leaf margins and shortly decurrent leaf bases with P. africana Steph. from West Africa. The latter species clearly differs from P. rodriguezii , however, in purely dichotomous branching, leaves horizontally spreading and very flat, ventral leaf base not ampliate but with a low shoulder (which may be differentiated into a small, inflated auricle on older leaves),larger leaf cells, c. 25 µm wide in midleaf, and presence of distinct underleaves (see Jones1962). Plagiochila africana is close to P. boivinii (see under the latter species).

Plagiochila liliputana Herzog , described from the Comores and a synonym of P. rodriguezii according to Grolle (1995), was reported from Madagascar by Vanden Berghen (1981). The Madagassan plant is a very different plant and and a synonym of P. repanda var. perrotana .

Figures

FIG. 16. ― Plagiochila rodriguezii Steph.: A, habit; B, shoot in ventral view with terminal branch; C, shoot in dorsal view; D, leaves; E, G, portion of leaf margin; F, leaf apex;H, midleaf cells;I, branch with intercalary androecia.From Pócs 90115/F (EGR).Scale bars:A, 5 mm;B-D, 1 mm;E-G,0.25 mm; H, 0.05 mm; I, 1 mm.