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BOTANICAL EXPLORATION IN VENEZUELA - I 63
species may go back a long time in geological history
original segregation and ancestral home.
for their
Vesicarex Steyermark, gen. nov.
Folia evaginantia, ligulo marginibus cartilagineis. Flores dioicae.
Stigmata 2. Stylus rectus. Squamae cucullatae incurvatae, infra
apicem coalescentes, hyalinae. Flores foemineae cacumene appendiculata
carnosa. Perigynia 2-parietina.
Leaves sheathless, ligules grass-like with cartilaginous margins.
Flowers dioecious. Stigmas 2. Style straight, persistent at base.
Scales cucullate-incurved, margins joined below apex, hyaline.
Pistillate flowers subsessile, the summit of perigynium crowned by a
whitish fleshy somewhat lobed appendage. Perigynia with the pericarp
apparently 2-layered, separating at maturity into a whitish
somewhat thickened inner membrane, surrounding the achene, and a
firmer outer layer.
The generic name, from vesiculus or vesica, refers to the extra
sac-like membrane or inner layer of the pericarp which encloses the
achene.
Vesicarex collumanthus Steyermark, sp. nov.
Planta caespitosa acaulescens vel subacaulescens; foliis glaucis
caeruleo-viridibus patentibus, supra sulcatis, subtus prominente
costatis, 1.3 cm. longis, 1-2.5 mm. latis, glabris vel marginibus et
costa inferiore scabridis; ligulo ore brunneo obtuso; floribus foemineis
subsessilibus; spiculis capitulis ovoideis 4-floris, 4 mm. longis,
2 mm. latis; squamis flores subtendentibus hyalinis, 3.75-5.5 mm.
longis, 3 ram. latis, ovatis cuspidatis; appendice 0.5 mm. longo; perigyniis
subcapitatis congestis terminalibus, 4.5-5.5 mm. longis, 1.5-
2.25 mm. latis, plano-convex is, biconvexis, vel obscure trigonis,
2-angulatis, elliptico-oblongis, glabris basi rotundatis, sensira in
rostrum attenuatis, ore bidentato; achaenio lenticulari-subtereti vel
trigono, ovato- vel late oblongo-elliptico, 2-3 mm. longo, 1.2-1.5 mm.
lato, superne et infeme angustato, minute puncticulato.
Plant in dense rosettes; leaves subcoriaceous, complicate, the
lower crowded portions of the sheathless leaves subimbricate,
membranaceous, whitish, 10-nerved; orifice conspicuously protruded
upward; pistillate flowers subsessile or shortly pedicellate, the
pedicels about 0.5 mm. long; spikelets terminal; pistillate scales
with central midrib prominent, the other 2 lateral nerves scarcely
prominent, shorter than the perigynia, but as broad as and clasping
the perigynia at the base; perigynia firmly membranaceous, congested,
fulvous- or olivaceous-brown, somewhat shining, faintly
3-4-nerved on one side, rather obscurely or not nerved elsewhere;
achene about half filling the perigynium, lenticular-subterete when
immature, trigonous when mature, dark brown (Fig. 8, a-f).