GrassBase - The Online World Grass Flora


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

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

Orthoclada laxa

HABIT Perennial; caespitose. Rhizomes absent. Culms erect, or decumbent; 50–120 cm long; rooting from lower nodes. Leaf-sheaths pilose; with hooked hairs. Ligule a ciliolate membrane. Leaf-blade base simple; with a false petiole. Leaf-blades lanceolate, or oblong; 10–20 cm long; 17–25 mm wide. Leaf-blade venation with distinct cross veins. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; effuse; 10–35 cm long; with spikelets clustered towards branch tips. Primary panicle branches not whorled. Panicle branches capillary; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 1–2 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 8–10 mm long; falling entire.

GLUMES Glumes similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume lanceolate; 3.5–5 mm long; 1 length of upper glume; herbaceous; 1-keeled; 3 -veined. Lower glume primary vein scaberulous. Lower glume surface asperulous. Lower glume apex acute. Upper glume ovate; 3.5–5 mm long; 0.8 length of adjacent fertile lemma; herbaceous; 1-keeled; 5 -veined. Upper glume primary vein scaberulous. Upper glume surface asperulous; rough on veins. Upper glume apex acute.

FLORETS Fertile lemma ovate; 5–6 mm long; herbaceous; keeled; 5–7 -veined. Lemma midvein scaberulous. Lemma apex acuminate. Palea fused below to rhachilla internode; oblong; 1 length of lemma; 2 -veined. Palea keels scaberulous. Apical sterile florets 1 in number; barren; linear; 0–2 mm long.

FLOWER Lodicules 2. Anthers 2; 0.5–1 mm long.

FRUIT Caryopsis with adherent pericarp. Embryo 0.25 length of caryopsis. Hilum punctiform.

DISTRIBUTION South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Centotheceae. WDC.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.