Plagiochila fracta Pócs

Gradstein, S. Robbert & Reeb, Catherine, 2022, The genus Plagiochila (Dumort.) Dumort. (Marchantiophyta) in Madagascar, Cryptogamie, Bryologie 20 (5), pp. 65-106 : 78-79

Plagiochila fracta Pócs

( Fig. 7)

Plagiochila fracta Pócs, Phytotaxa 195 (2): 183 (2015) . — Type: Madagascar. Prov. Antsiranana, Manongarivo-Ambahatra Reserve, on ridge between the two branches of Mt. Ambahatra, c. 800 m, on rock in montane forest, 1250-1300 m, III.1999, Geissler19691/1 (holo-, G00281722; iso-, EGR; fide Pócs 2015).

DISTRIBUTION AND HABITAT. — Only known from the type from Madagascar.

DESCRIPTION (after Pócs 2015)

Plants very small, 0.8-1.3 mm wide, to 1 cm long, very flaccid, irregularly branched, branches intercalary, rhizome-like creeping shoot present. Mature stem leaves contiguous, rather widely and horizontally spreading, sligthly asymmetrically oblong-ligulate, c. 2-3× longer than wide, widest in the middle, very fragile, irregularly fragmenting in the upper half, base not ampliate and not shouldered, apex rounded or 2-4 lobulate, without teeth; leaf bases shortly and narrowly decurrent. Leaf cells somewhat elongate, c. 15-2 µm wide in midleaf, with small trigones; leaf base without vitta-like area; cuticle smooth; oil bodies probably granular. Underleaves minute. Androecia slender, terminal to intercalary, with 3-5 pairs of bracts. Perianth campanulate, without stalk, perianth mounth laciniate. Vegetative reproduction by leaf fragmentation.

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NOTES

Plagiochila fracta (sect. Heteromallae Lindenb.) is recognized by the very small plants with intercalary branching and horizontally spreading, oblong-ligulate, entire or shallowly 2-4

lobed leaves that are strongly fragmenting in the upper half ( Pócs 2015). The species may be related to P. pectinata , but the latter is a larger plant with ventrad, toothed leaves that are caducous, not fragmenting.