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.

Tuctoria

HABIT Annual. Culms erect (1), or geniculately ascending (2), or decumbent; 5–21.33–50 cm long. Leaves without demarcation between sheath and blade. Ligule absent. Leaf-blades persistent (2), or deciduous at the ligule (1); viscid; aromatic.

INFLORESCENCE Inflorescence composed of racemes; exserted (1), or embraced at base by subtending leaf (2).

Racemes single; multilateral. Rhachis angular. Spikelet packing broadside to rhachis; contiguous (2), or distant (1).

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–6 fertile florets (1), or 7–9 fertile florets (2), or 10 fertile florets, or 11–40 fertile florets (1); with diminished florets at the apex. Spikelets oblong; laterally compressed; 10–13.33–23 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite.

GLUMES Glumes persistent; shorter than spikelet. Lower glume ovate; 1 length of upper glume; chartaceous; without keels; 7 -veined. Lower glume surface without pits. Lower glume apex entire (2), or erose (1), or with a unilateral tooth (1), or dentate (1); 1–2 -fid (1/1); acute (2/2); muticous (2), or mucronate (1). Upper glume oblong; 0.75–0.9583–1 length of adjacent fertile lemma; chartaceous; with undifferentiated margins (2), or hyaline margins (1); without keels; 7–9 -veined. Upper glume apex entire (2), or erose (1), or with a unilateral tooth (1), or dentate (1); 1–2 -fid (1/1); acute (2/2); muticous (2), or mucronate (1).

FLORETS Fertile lemma oblong; chartaceous; of similar consistency on margins (2), or much thinner on margins (1); keeled; wingless; 5 -veined (1), or 9–10 -veined (1), or 11–13 -veined (2), or 14–15 -veined (1). Lemma lateral veins ribbed. Lemma surface smooth (2), or scaberulous (1); unwrinkled; without grooves. Lemma apex entire (1), or erose; truncate (1), or acute (2); mucronate. Palea 1 length of lemma; 2 -veined. Palea keels smooth (2), or scaberulous (1). Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; free (1), or adnate to palea (2); fleshy; truncate. Anthers 3. Stigmas 2; sparsely hairy.

FRUIT Caryopsis with adherent pericarp; oblong (2), or obovoid (1); laterally compressed; smooth (1), or rugose (2). Embryo 0.75–0.7917–1 length of caryopsis.

DISTRIBUTION North America.

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