Endogemma
Endogemma is a monotypic genus of liverworts belonging to the family Endogemmataceae and subclass of Jungermanniineae.
The genera Endogemma and fellow Jungermanniineae subclass genus Solenostoma was also accepted by Borovichev 2014, and Konstantinova & Lapshina 2014.
The only known species is Endogemma caespiticia.
The family Endogemmataceae, the genus Endogemma and the lone species Endogemma caespiticia were all published by Konstant., Vilnet et A.V.Troitsky in Folia Cryptog. Estonica 48: 132 in 2011.
It has the beaked perianth mouth of Solenostoma and a lack of perigynium and shoot calyptra as in Jungermannia species. It differs from similar Solenostomataceae and Jungermanniaceae species in having endogenous gemmae and in a characteristic large, single oil-body otherwise only known for Solenostoma tetragonum.
The name Endogemma is derived from endogenous and gemmae. This is a very rare feature in hepatic plants. The species epithet of caespiticia is derived from caespiticius meaning made of turf.
It is commonly known as the delicate flapwort, or carpet-like flapwort.
Description
Endogemma caespiticia has obliquely, or sub-transversely inserted leaves, that un-lobed and rounded. They are wide and long but very rarely up to 5 mm long. It has a creeping to ascending form, with endogenous gemmae concentrated in unfertilized perianths. The plants are pale brownish, whitish to yellowish, without red or purple pigmentation.The stem is 200–300 μm wide with lateral branching, mainly below gemmae tips or perianths.
The dorsal surface cells are thin-walled, with indistinct trigones which are 70–240 by 28–50 μm in size.
Rhizoids are dense to scattered and colour-less to brownish in shade. They are in indistinct obliquely spreading fascicles commonly closely attaching plant to the substratum or soils.
The cells in the midleaf, are thin-walled, from 28 × 28 μm up to 47–90 × 42–65 μm in size. The cells near the margins are 40–70 μm in size. They are thin-walled, but sometimes with a thickened external wall. The trigones are concave, with a cuticle smooth throughout. There are oil bodies in almost all of the leaf cells, 1 or 2 per cell. They are grayish to brownish and are coarsely granulate and nearly filling the cell lumen. The gemmae are ovoid or ellipsoidal shaped, orbicular to shortly elliptic, and irregularly tetragonal in projection. They are about 8.4–14.0 × 7.0–10 μm in size. They are 2 celled at leaf tips or margins. They are found within unfertilized perianth. The sexual condition is dioicous. The perianth is present, without perigynium or shoot calyptra.