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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.
Stipa ambigua
HABIT Perennial; caespitose. Culms erect; 50–100 cm long. Culm-internodes distally glabrous. Lateral branches lacking. Leaf-sheaths glabrous on surface; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule an eciliate membrane; 0.2 mm long. Leaf-blades filiform; convolute; 20–45 cm long; 0.6 mm wide. Leaf-blade surface glabrous. Leaf-blade margins ciliate. Leaf-blade apex attenuate; pungent.
INFLORESCENCE Inflorescence a panicle; exserted, or embraced at base by subtending leaf.
Panicle open; 20–45 cm long; bearing few spikelets.
Spikelets solitary. Fertile spikelets pedicelled.
FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 6–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; curved; 0.5–1 mm long; pilose; acute.
GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 6–10 mm long; 1 length of upper glume; hyaline; yellow, or purple; without keels; 3 -veined. Lower glume apex acuminate. Upper glume lanceolate; 6–10 mm long; 1.5–2 length of adjacent fertile lemma; hyaline; yellow, or purple; without keels; 3 -veined. Upper glume apex acuminate.
FLORETS Fertile lemma lanceolate; subterete; 4–5.5 mm long; chartaceous; without keel; 5 -veined. Lemma surface pubescent; with conspicuous apical hairs. Lemma margins flat; covering most of palea. Lemma hairs 2–4 mm long. Lemma apex surmounted by a ring of hairs; awned; 1 -awned. Principal lemma awn bigeniculate; 25–30 mm long overall; with 14–24 mm long limb; with twisted column; deciduous. Column of lemma awn 3–7 mm long. Palea 3–4 mm long; 0.8 length of lemma; chartaceous; 2 -veined; without keels. Palea surface pilose (1–2mm); hairy on back.
FLOWER Lodicules 3. Anthers 3; 1.5–2.5 mm long; anther tip smooth. Stigmas 2. Styles free to the base. Ovary glabrous.
FRUIT Caryopsis with adherent pericarp; fusiform; 2.5–3.5 mm long; dark brown; striate. Hilum linear; 0.66–0.75 length of caryopsis.
CLEISTOGENES AND VIVIPARY Cleistogenes present; in lower sheaths.
DISTRIBUTION South America: southern South America.
NOTES Stipeae. Torres 1994.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
