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.

Jansenella

HABIT Annual. Culms erect (1), or geniculately ascending (1), or decumbent (1); slender (1/1); 10–23.75–40 cm long; rooting from lower nodes. Ligule an eciliate membrane. Leaf-blades lanceolate; firm, or flaccid (1).

INFLORESCENCE Inflorescence a panicle.

Panicle open.

Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or oblong (1), or ovate (1); laterally compressed; 5–7.75–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose (1/1).

GLUMES Glumes persistent; reaching apex of florets (1), or exceeding apex of florets (1); thinner than fertile lemma. Lower glume ovate; 0.5–0.575–0.6 length of upper glume; membranous; without keels; 3 -veined. Lower glume surface without pits; glabrous (1), or pilose. Lower glume apex acute; awned. Upper glume lanceolate (1), or oblong (1); 1 length of adjacent fertile lemma; membranous; without keels; 3–4 -veined (1), or 5 -veined. Upper glume surface smooth (1), or scabrous (1); glabrous (1), or pilose; with tubercle-based hairs. Upper glume apex acute; awned; 1 -awned (1/1).

FLORETS Basal sterile florets male, or barren; with palea. Lemma of lower sterile floret lanceolate (1), or oblong (1); 0.9–0.95–1 length of fertile lemma; membranous; 3 -veined, or 4–5 -veined (1); obtuse (1/1); awned. Palea of lower sterile floret winged on keels. Fertile lemma oblong; chartaceous (1), or coriaceous; without keel; wingless; 3 -veined. Lemma surface unwrinkled; without grooves; glabrous (1), or pilose; with marginal hair tufts (1), or with a transverse row of hair tufts (1). Lemma margins involute; interlocking with palea keels. Lemma apex lobed; 2 -fid; incised 0.3–0.35–0.4 of lemma length; awned; 3 -awned. Principal lemma awn from a sinus; geniculate. Lateral lemma awns shorter than principal. Palea 2 -veined. Palea keels winged. Palea surface glabrous (1), or pubescent (1). Palea apex dentate.

FLOWER Lodicules 2 (1/1); fleshy (1/1). Anthers 3. Stigmas 2.

FRUIT Caryopsis with adherent pericarp; ellipsoid (1), or oblong (1); dorsally compressed; plano-convex. Embryo 0.5 length of caryopsis. Hilum punctiform.

DISTRIBUTION Tropical Asia.

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