Sporobolus diandrus (Retz.) P.Beauv.

synonyms: Sporobolus diander


Indian dropseed


Info

Subfamily: Chloridoideae
Genus etymology: Sporobolus = "seed thrower" referring to the seed being ejected from the pericarp
Species etymology: diandrus = "two anthers" [Latin] refering to two anthers per floret
Photosynthetic type: C4 (warm season)
Nativity: naturalized - accidental
First recorded in Hawaiʻi: 1911

Map

 Distribution of Sporobolus diandrus in Hawaiʻi.

Inflorescence

Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence
Sporobolus diandrus Inflorescence

Plant

Sporobolus diandrus Plant

Habit

Sporobolus diandrus Habit
Sporobolus diandrus Habit
Sporobolus diandrus Habit

Spikelets

Sporobolus diandrus Spikelets
Sporobolus diandrus Spikelets
Sporobolus diandrus Spikelets
Sporobolus diandrus Spikelets

Collar

Sporobolus diandrus Collar

Description

Plants perennial; cespitose, not rhizomatous. Culms 30-80 cm. Sheaths keeled or rounded; ligules 0.2-0.5 mm; blades 10-30 cm long, 2-4 mm wide, flat, becoming folded. Panicles 15-35 cm long, 0.4-4 cm wide, contracted to rather lax and open; primary branches appressed to strongly ascending, without spikelets on the lower XA, lower branches much longer than the internodes; pedicels 0.1-3 mm. Spikelets 1.3-1.8 mm, plumbeous to greenish. Lower glumes 0.4-0.8 mm, acuminate to truncate; upper glumes 0.7-1 mm, usually less than H as long as the florets, rarely longer, faintly 1-veined, truncate, erose to denticulate; lemmas 1.2-1.6(1.8) mm, elliptic, glabrous, 1-veined, acute to obtuse; paleas 1.4-1.8 mm, elliptic; anthers 2(3), 0.5-0.8 mm. Fruits 0.7-0.9 mm, quadrangular, laterally compressed, reddish-brown, truncate. 2n = 12.
(Description source: Barkworth, M.E., Capels, K.M., Long, S. & Piep, M.B. (eds.) 2003. Flora of North America, north of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, Part 2. Oxford University Press, New York. 783 pp. http://floranorthamerica.org/Sporobolus_diandrus )

Perennials; culms tufted, erect from a geniculate base, slender, 3-7 dm tall, glabrous. Sheaths glabrous, compressed, sometimes sparsely pilose at throat; ligule membranous, shallow, margins fimbriate; blades linear, flat, involute when dry, 1-2 (-4) mm wide, glabrous or with a few hairs on the upper surface. Panicles narrow, somewhat diffuse, up to 30 cm long, the branches ascending to spreading, 2-3 cm long near base; spikelets numerous, clustered along the branches, slightly compressed, 1.3-1.5 mm long, glabrous, short pedicellate; glumes unequal, first glume ca. 0.3 mm long, apex truncate, second glume ovate, ca. 0.5 mm long, apex obtuse; lemma grayish green, ovate, ca. 1.4 mm long, 1-nerved, apex acute; palea ovate, ca. 1.3 mm long, grayish green, nerveless. Fruit green to brown, cuboid-oblong, 0.6-0.8 mm long. [2n = 24, 36, 48.]
(Description source: O’Connor, P.J. 1990. Poaceae, pp. 1481–1604. In: Wagner W.L., Herbst D.R. & Sohmer S.H. (eds.)., Manual of the flowering plant of Hawaiʻi. Vol. 2. University of Hawaii Press & Bishop Museum Press, Honolulu )