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.

Oryza

HABIT Annual (7), or perennial (12). Rhizomes absent (11), or short (5), or elongated (3). Culms erect (11), or geniculately ascending (10), or decumbent (8), or prostrate (1); robust (1/2), or of moderate stature (1/2); 30–109.3–300 cm long; spongy (4), or firm (15); rooting from lower nodes (4/4). Culm-nodes constricted (3/3). Lateral branches lacking (1/1). Leaf-sheath auricles absent (10), or erect (5), or falcate (4). Ligule an eciliate membrane (18), or a ciliolate membrane (1). Leaf-blade base without a false petiole (18), or with a brief petiole-like connection to sheath (1). Leaf-blades linear (18), or lanceolate (3). Leaf-blade midrib indistinct (1/1), or evident (1/1).

INFLORESCENCE Inflorescence a panicle; exserted (18), or embraced at base by subtending leaf (1).

Panicle open (17), or contracted (2). Primary panicle branches not whorled (16), or whorled at lower nodes (2), or whorled at most nodes (1).

Spikelets appressed (4/5), or spreading (1/5); solitary (18/18). Fertile spikelets pedicelled. Pedicels linear; tip cupuliform (15/15), or lobed (2/15).

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic (8), or oblong (12), or ovate (4), or orbicular (1); laterally compressed; symmetrical (18), or gibbous (1); 1.5–6.939–12 mm long; persistent on plant (2), or falling entire (17). Spikelet callus glabrous (12/12); base truncate (11/11); attached transversely (2/6), or attached obliquely (4/6). Rhachilla internodes brief up to lowest fertile floret (16), or elongated below proximal fertile floret (3). Rhachilla elongation stout (2/2).

GLUMES Glumes both absent or obscure.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret subulate (3), or linear (5), or lanceolate (12), or oblong (2); membranous (7/10), or herbaceous (1/10), or coriaceous (2/10); 1 -veined (14/14); emarginate (1/10), or acute (7/10), or acuminate (3/10); muticous (15/16), or awned (1/16). Fertile lemma elliptic (11), or oblong (7), or orbicular (3); laterally compressed; not gibbous (18), or gibbous (1); chartaceous (1), or coriaceous (18); keeled; wingless; 5 -veined. Lemma midvein without distinctive roughness (8), or spinulose (11); eciliate (15), or ciliate (3), or hispid (1). Lemma surface granulose (3), or scaberulous (3), or scabrous (4), or striate (1), or reticulate (12); unwrinkled; without grooves; glabrous (14), or hispidulous (5), or hispid (4); with simple hairs (8/9), or hooked hairs (1/9). Lemma margins interlocking with palea margins (10), or involute (9); eciliate (18), or ciliolate (1). Lemma apex acute (2/14), or rostrate (11/14), or caudate (1/14); muticous (5), or awned (15); 1 -awned (15/15). Principal lemma awn straight (15/15), or flexuous (2/15). Palea 0.9–0.9778–1 length of lemma; chartaceous (1), or coriaceous (17), or indurate (1); 3 -veined (18), or 5 -veined (1); without keels (1), or 1-keeled (18). Palea keels smooth (6/18), or scabrous (7/18), or spinulose (5/18). Palea surface glabrous (18), or pubescent (1). Palea apex muticous (14), or with excurrent keel veins (1), or awned (5).

FLOWER Lodicules 2; membranous. Anthers 6 (17/17). Stigmas 2.

FRUIT Caryopsis with adherent pericarp (17/17); lanceolate (1/5), or ellipsoid (2/5), or oblong (2/5), or ovoid (1/5). Embryo 0.1–0.15–0.2 length of caryopsis. Hilum linear (1/1).

DISTRIBUTION Europe (1), or Africa (7), or Temperate Asia (5), or Tropical Asia (10), or Australasia (4), or Pacific (2), or North America (2), or South America (4).

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