Sphenopus divaricatus (Gouan)
Rchb.
|
Derivation
Sphenopus Trin., Fund. Agrostogr. 135 (1822); from the Greek sphen
(wedge) and pous (foot), in reference to the distally thickened pedicels.
divaricatus- from the Latin divarico (spread out). Inflorescence branches or culms regularly dividing into equal branches.
Published in
Fl. Germ. Excurs. 45 (1830).
Habit
Annual. Culms erect or decumbent, 2.530 cm tall. Mid-culm nodes black.
Ligule an eciliate membrane, 0.64 mm long, obtuse or acute. Leaf-blades
filiform, convolute, 0.85 cm long, 0.31 mm wide. Leaf-blade apex
obtuse, hooded.
Inflorescence
Inflorescence compound, a panicle. Panicle open, ovate, 1.510 cm long.
Primary panicle branches 2-nate, branching divaricately. Panicle branches capillary.
Spikelets
Spikelets solitary. Pedicels cuneate, 24 mm long. Fertile spikelets many
flowered, comprising 25 fertile florets, with diminished florets at
the apex, elliptic, laterally compressed, 1.93 mm long, breaking up at
maturity. Spikelets disarticulating below each fertile floret.
Glumes
Glumes persistent, dissimilar, thinner than fertile lemma. Lower glume ovate
or orbicular, 0.10.4 mm long, 2040% length of upper glume, hyaline,
0-nerved. Lower glume apex obtuse. Upper glume oblong, 0.51 mm long, 2550%
of length of adjacent fertile lemma, hyaline, 1-keeled, (0)1-nerved. Upper
glume apex emarginate or obtuse.
Florets
Fertile lemma ovate, 1.22 mm long, membranous, keeled above, 3-nerved.
Lemma midnerve scabrous. Lemma apex truncate or obtuse, muticous. Palea keels
scabrous, adorned above. Apical sterile florets resembling fertile though underdeveloped.
Anthers 3, oblong, 0.20.6 mm long. Ovary glabrous. Grain with adherent
pericarp, oblong, 0.751.25 mm long. Embryo 2025% of length of
grain. Hilum punctiform.
Continental Distribution:
Europe, Africa, Temperate Asia, Australasia.
Australian Distribution:
South Australia: Eyre Peninsula, Northern Lofty, Yorke Peninsula, Southern
Lofty.
Classification. (GPWG
2001):
Pooideae: Poeae
Notes
Introduced. Salt swamps and lakes and sandy soils. Flowers MayOct.
Inflorescence and spikelet (photo)
© Watson and Dallwitz 1989
Inflorescence and spikelet (line drawing)
© Australian Biological Resources Study
drawing by Lesley Elkan