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.

Merostachys magellanica

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms erect; 600–800 cm long; 12–14 mm diam.; woody. Culm-internodes terete; hollow; 60–80 cm long; yellow and dark green; striped and mottled. Culm-nodes pubescent. Lateral branches dendroid. Branch complement many; flabellate; with subequal branches; thinner than stem. Culm-sheaths deciduous; 25–30 cm long; 5 times as long as wide; green; hairy on margins. Culm-sheath blade lanceolate; reflexed; 5–12 cm long; 12–15 mm wide; attenuate. Leaves 4–7 per branch. Leaf-sheaths tight; striately veined; glabrous on surface. Leaf-sheath oral hairs setose; erect; 3–10 mm long; dark. Ligule a ciliolate membrane; 0.5 mm long. Collar with external ligule. Leaf-blade base asymmetrical; with a brief petiole-like connection to sheath; petiole glabrous. Leaf-blades linear, or lanceolate; 8–17 cm long; 15–20 mm wide. Leaf-blade venation indistinct; without cross veins. Leaf-blade surface glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle cylindrical at apex, or tipped by a glumaceous appendage.

Racemes 1; single; arcuate; unilateral; 6–18 cm long. Rhachis pilose on surface; terminating in a sterile spikelet. Rhachis hairs white. Spikelet packing broadside to rhachis; contiguous; regular.

Spikelets pectinate, or spreading (at maturity); solitary. Fertile spikelets pedicelled. Pedicels oblong; ciliate.

STERILE SPIKELETS Apical sterile spikelets rudimentary.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 11–14 mm long; 1.8–2(–4) mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes elongated below proximal fertile floret. Rhachilla elongation 2.5 mm long; pubescent.

GLUMES Glumes persistent; shorter than spikelet. Lower glume ovate; 3–3.5 mm long; 0.5 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface pubescent. Lower glume apex acuminate. Upper glume ovate; 5.5–7.5 mm long; 0.5 length of adjacent fertile lemma; chartaceous; 9 -veined. Upper glume surface pubescent. Upper glume apex acuminate; mucronate.

FLORETS Fertile lemma oblong; 10–11.5 mm long; 5–5.5 mm wide; chartaceous; shiny; without keel; 14–15 -veined. Lemma surface pubescent. Lemma margins ciliate. Palea 10.5–12.5 mm long; chartaceous; 8–12 -veined. Palea keels contiguous above a sulcus; ciliolate. Apical sterile florets 1 in number; rudimentary.

FLOWER Lodicules 3; 3.3 mm long; veined; ciliate. Anthers 3; 9 mm long. Stigmas 2.

FRUIT Caryopsis with free brittle pericarp; oblong; sulcate on hilar side; 6–7 mm long; apex rostrate. Embryo 0.1 length of caryopsis. Hilum linear.

DISTRIBUTION South America: Brazil.

NOTES Bambuseae. Sendulsky 2001.

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