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.

Olmeca clarkiae

HABIT Perennial; caespitose. Rhizomes short; pachymorph; scaly. Culms erect; pendulous at the tip; 500–800 cm long; 10–16 mm diam.; woody. Culm-internodes terete; hollow; mid-green. Lateral branches dendroid; intravaginal. Bud complement 1. Branch complement one; solitary. Culm-sheaths persistent; glabrous, or pilose; without auricles; setose on shoulders; shoulders with 8–15 mm long hairs. Culm-sheath ligule 0.8–2 mm high. Culm-sheath blade lanceolate; spreading, or reflexed. Leaves 4–8 per branch. Leaf-sheaths pilose; hairs tawny; outer margin hairy. Leaf-sheath oral hairs setose; 7–15 mm long. Leaf-sheath auricles falcate (on one side); 0.5–1 mm long. Ligule a ciliolate membrane; 0.5–1 mm long. Collar with external ligule. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades linear, or lanceolate; 10–36 cm long; 9–15 mm wide. Leaf-blade venation with obscure cross veins. Leaf-blade surface scabrous; rough adaxially; puberulous; hairy abaxially. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle; without bracts, or bracteate at branch bases (lowest branch).

Panicle open; pyramidal; 10–33 cm long. Primary panicle branches spreading; 1 -nate; sparsely divided; branching divaricately; 7–15 cm long. Panicle axis puberulous. Panicle branches pubescent in axils; with prominent pulvini.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 2–8 mm long; glabrous.

FERTILE SPIKELETS Spikelets comprising 0 basal sterile florets (both florets fertile), or 1 basal sterile florets; 1–2 fertile florets; with a barren rhachilla extension. Spikelets linear, or lanceolate; subterete; 19–25 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 2.5–6 mm long; sparsely hairy.

GLUMES Glumes persistent; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 3–5 mm long; 0.6–0.7 length of upper glume; membranous; without keels; 3 -veined. Lower glume margins ciliate. Lower glume apex acute; awned; 1 -awned. Lower glume awn 2–5.5 mm long. Upper glume lanceolate; 5–7.2 mm long; 0.33–0.5 length of adjacent fertile lemma; membranous; without keels; 5–7 -veined. Upper glume margins ciliate. Upper glume apex acute; awned; 1 -awned. Upper glume awn 2.5–4.5 mm long.

FLORETS Basal sterile florets barren; with palea; separately deciduous. Lemma of lower sterile floret similar to fertile lemma; lanceolate; 9.5–10.5 mm long; 11–13 -veined; ciliate on margins; fringed above; awned. Awn of lower sterile floret 3–5.5 mm long. Palea of lower sterile floret 1.5–2 mm long; pubescent. Fertile lemma lanceolate; 13–15 mm long; chartaceous; without keel; 11–13 -veined. Lemma lateral veins with cross-veins. Lemma surface pubescent; hairy above and at base. Lemma margins ciliate; hairy above. Lemma apex acute; awned; 1 -awned. Principal lemma awn 4–5 mm long overall. Palea 1 length of lemma; 4 -veined. Palea surface glabrous, or pubescent; hairy on flanks; hairy above. Rhachilla extension 9–12.5 mm long; pubescent.

FLOWER Lodicules 3; lanceolate; 2–2.5 mm long; veined; ciliate. Anthers 3; 8.5–9.5 mm long. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Bambuseae. Davidse & Pohl 1995.

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