Bio 430

Contemporary Circumscription Compared with A Utah Flora 4th ed.

Bio430

Poaceae•Graminae

No difference at the family level; within the family, a number of species have been placed in new or different genera.

Key Features

Annual to perennial herbs, sometime woody (bamboo), with hollow stems, swollen nodes, open, sheathing leaf bases, and 2-ranked leaves. Flowers are zygomorphic and also highly modified. Individual flowers are surrounded by a pair of bracts called the Palea and Lemma, and these bracts plus the flower make a “Floret.” Florets are clustered into spiklets subtended by a pair of glumes. Spikelets are arranged into various inflorescence patterns such as racemes, and panicles. Other features useful for identifying species include the collar, auricles, and the ligule. The fruit is a caryopsis.

Bamboo (China)

Grass rhizome

Grass fibrous roots

Grass spiklets - what and where are the glumes?

at anthesis; anthers and stigmas protruding from lemma and palea apparent

Poa bulbosa

Poa bulbosa - identify open sheath, ligule, collar, blade, stem (=culm)

Poa bulbosa - inflorescence

Poa bulbosa - this species is viviparous, giving rise to plantlets in place of caryopses; its the only grass that grows from true bulbs

Two ranked leaves

Culm at node (left) and sectioned (right; upside down...oops). Right image shows hollow internode

Leaves with open sheaths, ligule, blade, collar

Two ranked leaves

Leaves with open sheaths, blade, collar (no ligule or auricles)

Miscanthus sinensis

Miscanthus culm with sheathing leaf base, collar, and blade

Miscanthus spiklets - each spikelet is surrounded by a ring of hairs

Miscanthus individual spiklet. The two glumes are apparent. The lemma and palea are membranous and hidden by the glumes, but the awn from the lemma is apparent.

Wheat caryopses

Corn caryopses

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