GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Thaumastochloa

HABIT Annual. Culms geniculately ascending (1/1), or decumbent (1/1); 7–29.31–70 cm long; rooting from lower nodes (1/1). Lateral branches ample (1/1). Ligule a ciliolate membrane. Leaf-blade margins cartilaginous (1/1).

INFLORESCENCE Inflorescence composed of racemes; terminal and axillary; not deciduous as a whole (7), or deciduous as a whole (2); subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear; herbaceous (1/1). Peduncle widened at apex; disarticulating.

Racemes single; linear (7), or moniliform (1); unilateral; bearing few fertile spikelets (4), or many spikelets (4); bearing 1 fertile spikelets on each (3), or 2–8 fertile spikelets on each (4), or 9 fertile spikelets on each (2), or 10 fertile spikelets on each (1). Rhachis tough (2), or fragile but the lowest internode fused to peduncle (7); subcylindrical and excavated; terminating in a sterile spikelet. Spikelet packing abaxial; 1 -rowed (2/6), or 2 -rowed (5/6). Rhachis internodes oblong (7), or inflated (1). Rhachis internode tip transverse (6), or oblique (4); crateriform.

Spikelets sunken; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels fused to internode.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong (3), or ovate (5); dorsally compressed; 1.6–2.837–4 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous (7/7); base truncate; simple (2), or with central boss (2), or with central peg (4); attached transversely (6), or attached obliquely (4).

GLUMES Glumes exceeding apex of florets; firmer than fertile lemma. Lower glume oblong (3), or ovate (5); indurate; 2-keeled; 5–6 -veined (1), or 7 -veined (6), or 8 -veined (1), or 9 -veined (3), or 10 -veined (1). Lower glume lateral veins without ribs (7), or ribbed (2). Lower glume surface convex (6), or flat (4), or concave (1); smooth (6), or rugose (2), or cancellate (1), or areolate (1); without pits. Lower glume apex obtuse (3), or acute (5). Upper glume elliptic; coriaceous; with hyaline margins; without keels; 5 -veined (1/1).

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret ovate (1/1); hyaline; 2 -veined (1/1); obtuse (1/1). Fertile lemma ovate (1/1); hyaline; without keel; wingless; 0 -veined (3), or 1 -veined (2), or 2 -veined (7), or 3 -veined (1). Lemma surface unwrinkled; without grooves. Lemma margins eciliate (7), or ciliolate (1). Lemma apex obtuse (1/1). Palea 0.9 length of lemma; hyaline (7), or membranous (1); 0–2 -veined (1/1); without keels (1), or 2-keeled (7).

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp (1/1); ovoid (1/1).

DISTRIBUTION Tropical Asia (3), or Australasia.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.