Dorstenia luamensis M. E. Leal, 2014

Leal, Miguel E., 2014, Dorstenia luamensis (Moraceae), a new species from eastern Democratic Republic of Congo, PhytoKeys 42, pp. 49-55 : 51-53

Dorstenia luamensis M. E. Leal sp. nov. Figs 1A, B, 2

Diagnosis.

Haec species notabilis ab omnibus Dorstenia speciebus differt ob filicinu lithophitu habitu novu familae

Type.

The Democratic Republic of Congo, Katanga Province, Tumbwe Sector, Luama Wildlife Reserve, M.E. Leal 2551 (holo LWI, iso BR), S5°14,526', E 28° 52,215', 1176m, 31 October 2012.

Description.

Lithophytes 10-17 cm long with a tuber 0.5 cm; stems aerial, hanging, glabrous; internodes 2.5-3 cm long; no white latex or translucent exu date. Stipules absent or deciduous without scars. Leaves distichous; blade narrowly subfalcate 5-7 × 1-1.4 cm, membranaceous, apex micrunate, base cunate, adaxial side glabrous and subspiculate, abaxial side white and glabrous; margins entire; petiole 1-2 mm long; venation brochidodromous; 5-7 pairs of secondary veins; tertiary veins scalariform. Receptacle elliptic to round, 3-4 mm in diameter, patelliform; margin greenish with triangular lobes (1 mm) and subspathulate appendages, 2-3 mm long; peduncle 1 mm long, glabrous. Staminate and pistilate flowers (7 to 8) tightly packed in receptacle: perianth short lobed, whit apex minutely 2-3 lobed, glabrous; stigma 0.1 mm long. Drupes and seeds are unknown.

Distinction from other species.

This new species can be distinguished from any other Dorstenia species by its fernlike habit, hanging from vertical rock faces and the absence of latex.

The new species is added to the existing key of Berg and Hijman (1999) the "key to succulent and semi-succulent species of the Old World"

1	Stems succulent and thick, internodes short; leaves subrosulate	section Acauloma
1'	Stems (semi-)succulent, or herbaceous, internodes long; leaves spaced, sometimes crowded at stem apices	section Kosaria , 2
2	Plants stem hanging
3	Plant lithophyte, multiple appendages	Dorstenia luamensis
3'	Plant epiphyte, one appendage	Dorstenia astyanactis
2'	Plants stem erect to ascending
4	Plants annual, without a rhizome or a tuber	Dorstenia annua
4'	Plants perennial, with rhizome or a tuber
5	Petiole relatively short, (0-)0.1-0.2(-0.5) cm long	Dorstenia benguellensis
5'	Petiole relatively long (0.2-)0.5-2.5(-3) cm long	other species of section Kosaria

Phenology.

The specimens were collected in late October.

Ecology.

Dorstenia luamensis M.E.Leal inhabits moist and shady vertical rock faces close to small waterfalls in forest within a riverine forest-open woodland-savanna mosaic.

Distribution and conservation status.

The species is distributed in small populations within the type locality, and according to these demographic characteristics it merits the conservation status of endangered (EN).

Etymology.

The epithet luamensis refers the Luama Wildlife Reserve which is drained by the Luama River.