Glossary table of contents

grass glossary

Grass morphology is described here.

Spikelet morphology is illustrated here.

auricle: A short appendiage at the base of the leaf blade, typically clasping the sheath. [Jepson]
awn: A bristle extending from the midrib of the lemma. It may extend from the tip of the lemma from from the outer surface. [Jepson]
callus: The enlarged, hard base of a lemma. [Jepson]
floret: A unit of a spikelet, composed of a flower or caryopsis (fruit) enclosed by a nested pair of bractlets, the palea on the inside, and the lemma on the outside. [Jepson]
glume: A bract (usually in a pair) at the base of a spikelet. [Jepson]
lemma: The outer bractlet enclosing the floret. [Jepson]
palea (paleae): The inner bractlet enclosing the floret. [Jepson]
rachis: The part of a grass stem along which flower stalks are spaced at short intervals. [Jepson]
spikelet: The rough equivalent of an inflorescence for grasses. A spikelet is one or more florets growing alternately along a rachilla. Multiple spikelets may be borne along the rachis. Note that a spikelet is not necessarily related to a spike. [Jepson]

Inflorescence shapes

Within the grasses, these terms describe the organization of multiple epikelets in a larger inflorescence. The order of development among spikelets is not defined.

panicle: An inflorescence in which at least some spikelets are attached to inflorescence branches rather than the central axis. The order in which heads develop is not defined. [Jepson, flower glossary]
raceme: An inflorescence with stalked spikelets attached directly to the inflorescence axis (not to branches). [Jepson, flower glossary]
spike: An inflorescence with sessile spikelets attached directly to the inflorescence axis (not to branches). [Jepson, flower glossary]
umbel: An inflorescence in which 3+ stalked spikelets radiate from a common point with no continuation of the central axis. [Jepson, flower glossary]