Glossary for Poaceae

For terms not listed here, see the Plant Glossary.

Line drawings of plant features.
Awn
— A stiff bristle situated at the tip of a glume or lemma.
Caryopsis
— A seed-like fruit with a thin outer wall; a grain.
Collar
— The junction of the leaf sheath and blade.
Culm
— The stem of a grass.
Floret
— A single small flower, usually a member of a cluster, such as a spikelet or a head.
Glume
— The lowest two (sometimes one) empty scales subtending the usually fertile scales in grass spikelets.
Lemma
— The lowermost of the two scales forming the floret in a grass spikelet -- the uppermost, less easily seen, is called the palea.
Ligule
— An extension, often scarious (papery), of the summit of the leaf sheath.
Nerve
— Same as a vein. The central vein running lengthwise on a scale
Node
— The point along a stem which gives rise to leaves, branches, or inflorescences.
Palea
— The uppermost of the two scales forming the floret in a grass spikelet (often obscure or hidden).
Rachilla
— A secondary rachis. The axis of a spikelet.
Sheath
— A tubular structure effected by the formation of leaf margins around the stem. The base of a grass leaf that runs from the node up to the blade.
Spikelet
— A secondary or small spike; specifically, in the Poaceae family, the unit composed or one or two glumes subtending one to several sets of lemma and palea combinations.

Family Glossaries

Contents of Plates

Plate 1:
Stem and Root Types.
Plate 2:
Leaf Composition, Parts, and Types.
Plate 3:
Leaf Shapes.
Plate 4:
Leaf Margins.
Plate 5:
Leaf Apices, Venation, and Bases.
Plate 6:
Surface Features.
Plate 7:
Stem and Leaf Parts, and Variations.
Plate 8:
Inflorescence Types.
Plate 9:
Floral Morphology.
Plate 10:
Corolla Types.
Plate 11:
Fruit Types.
Plate 12:
Sedges, Grasses, and Composites.

Information provided on this page applies to the Chicago Region and may not be relevant or complete for other regions.

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