Zea

HABIT Annual (4), or perennial (2). Rhizomes absent (4), or short (1), or elongated (1). Culms erect; robust (1/2), or of moderate stature (1/2); 100–245.8–500 cm long; with prop roots (3/3). Lateral branches lacking (1/1). Ligule an eciliate membrane. Leaf-blades linear (4), or lanceolate.

INFLORESCENCE Monoecious. Inflorescence composed of racemes; axillary; subtended by a spatheole; enclosed. Spatheole elliptic; herbaceous.

Racemes single; bilateral (5), or multilateral (1); bearing 4 fertile spikelets on each (1/2), or 5–10 fertile spikelets on each (2/2). Rhachis tough (1), or fragile at the nodes (5); subcylindrical and excavated (5), or enlarged into a woody cob (1). Spikelet packing crowded (1), or contiguous (5); 2 -rowed (2/3), or 4–11 -rowed (1/3). Rhachis internodes indefinite (1), or inflated (5). Rhachis internode tip oblique (5/5); flat (3/5), or cupuliform (2/5).

Spikelets sunken; solitary (5), or in pairs (1). Fertile spikelets sessile; 2 in the cluster (1/1). Male spikelets sessile (1/5), or sessile and pedicelled (5/5); 2 in a cluster (5/5).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong (4), or obovate (1), or rhomboid (1); laterally compressed (5), or dorsally compressed (1); 4–5.333–8 mm long; persistent on plant (1), or falling entire (5); deciduous with accessory branch structures (5/5).

GLUMES Glumes reaching apex of florets; firmer than fertile lemma. Lower glume oblong (5), or oblate (1); scarious (1), or coriaceous (2), or indurate (3); without keels; 0 -veined (1/1). Lower glume lateral veins absent (1), or distinct (5). Lower glume surface without pits. Upper glume elliptic (5), or oblate (1); membranous (5), or scarious (1); without keels; 0 -veined (1/1).

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret ovate (1/1); membranous; 0 -veined (1/1). Fertile florets female. Fertile lemma elliptic (5), or orbicular (1); hyaline (5), or membranous (1); without keel; wingless; 0 -veined (1/1). Lemma surface unwrinkled; without grooves.

FLOWER Lodicules absent (1/1), or 2 (1/1). Anthers 3. Stigmas 2; papillose.

FRUIT Caryopsis with adherent pericarp.

MALE Male inflorescence terminal; unlike female; of subdigitate racemes (2), or of racemes along a central axis. Male spikelets distinct from female; elliptic (5/5). Male spikelet glumes 2; muticous. Male spikelet lemma muticous.

DISTRIBUTION Europe (1), or Africa (3), or Temperate Asia (2), or Tropical Asia (2), or Australasia (2), or Pacific (1), or North America (4), or South America (3).

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