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Pakistan | Family List | Poaceae


Annual or perennial herbs. Leaf-blades linear, often with small auricles; ligule membranous. Inflorescence a spike, the spikelets or clusters of 2-3(-7) spikelets alternating on opposite sides of a tough or fragile rhachis Spikelets all alike or the lateral spikelets of a cluster shortly pedicelled and male or barren and much reduced, usually laterally compressed, 1-many-flowered; rhachilla disarticulating below each floret, sometimes the spikelet and its supporting internode falling entire. but the rhachilla and rhachis tough in cultivated cereals; glumes persistent, well-developed, as long as or shorter than the spikelet, sometimes narrow and awn-like; lemmas coriaceous, 5-9-nerved, awnless or with a straight or curved awn from the tip; palea hyaline, as long as the lemma; lodicules 2; stamens 3; ovary with a hairy apical appendage and 2 stigmas. Grain with small embryo and linear hilum; starcn grains simple, rounded. Chromosomes large, basic number 7.

Genera ± 15; temperate regions generally, including the main temperate cereals and many weeds of cultivation; 12 genera and 47 species in Pakistan.

The tribe can usually be recognised by its spicate inflorescence. It is allied to Poeae, but the endosperm contains simple starch grains of a distinctive rounded shape. Owing to the facility with which wide crosses may be made, there is much disagreement over the number of genera which should be recognized within the tribe.

Hystrix duthiei (Stapf) Bor and Psathyrostachys caduca (Boiss.) Meld., although reported from Pakistan, remain unconfirmed.

1 Spikelets solitary at each node of the rhachis   (2)
+ Spikelets in groups of 2-6 at each node of the rhachis   (9)
2 (1) Spikelets 1-2-flowered, awnless, sunk into the jointed fragile spike-axis and closely appressed to it; florets covered by the collateral glumes; lemmas thin, membranous   Henrardia
+ Spikelets 2-12-flowered, awned or awnless, not sunk into the spike-axis, lightly appressed to it or divergent; florets, at least the upper, exceeding the glumes; glumes not collateral; lemmas herbaceous to coriaceous   (3)
3 (2) Spikelets dimorphic, the fertile hairy and warty, the sterile scale-like   Heteranthelium
+ Spikelets all alike or the uppermost reduced or aborted   (4)
4 (3) Spikelets 2-flowered; keels of the lemma prominently pectinate-ciliate; glumes subulate   Secale
+ Spikelets more than 2-flowered; lemma not pectinate-ciliate on the keel; glumes not subulate   (5)
5 (4) Nerves of the lemma not confluent at the tip; annuals   (6)
+ Nerves of the lemma confluent at the tip; annuals or perennials   (7)
6 (5) Glumes and lemmas keeled on the back; caryopsis free between the lemma and palea, easily removed by threshing (cultivated wheat)   Triticum
+ Glumes and lemmas rounded on the back; caryopsis closely enfolded by the lemma and palea, adnate to them, not removed by threshing (wild grasses)   Aegilops
7 (5) Spike-axis fragile   Eremopyrum
+ Spike-axis tough   (8)
8 (7) Glumes boat-shaped, keeled; spikelets pectinate, diverging from the rhachis at a wide angle   Agropyron
+ Glumes not boat-shaped, rounded on the back; spikelets ± appressed to the rhachis   Elymus
9 (1) Spikelets 1-flowered, the rhachilla produced and bearing a second, vestigial floret   (10)
+ Spikelets usually 3-5-flowered   (11)
10 (9) Spikelets in pairs at each node of the rhachis   Taeniatherum
+ Spikelets in threes at each node of the rhachis   Hordeum
11 (9) Spike-axis partly tough, partly fragile; sterile hybrid   x Elyhordeum
+ Spike-axis tough throughout   (12)
12 (11) Glumes subulate,1-nerved; awn of lemma short, not more than 3 mm long   Leymus
+ Glumes broader, several-nerved; awn of lemma at least 10 mm long   Elymus

  • List of lower taxa


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