Lemma
Definition
The lower of the two bracts enclosing the grass floret. Its surface texture, venation, awn character, and marginal features are major identification characters at genus level.
- Location
- Lower bract of a grass floret
- Field
- Grass and phytolith identification
- Diagnostic features
- Texture, venation, awn, margins
- Taxonomic level
- Genus
Common questions
Why is the lemma useful for forensic botanical identification?+
Its surface and structural features vary consistently between grass genera, so a lemma fragment recovered as trace evidence, for example on clothing or a vehicle, can help narrow the plant source to a genus even when the rest of the plant material is fragmentary.
What is the lemma's counterpart structure called?+
The palea is the companion bract that, together with the lemma, encloses the grass floret; comparing both structures together, where present, gives a more reliable identification than the lemma alone.
Related terms
- Caryopsis
- The grain of a grass: a single-seeded fruit in which the seed coat is fused to the ovary wall. Shape, size, and...
- Floret
- The basic reproductive unit of a grass spikelet, consisting of the lemma, palea, and the enclosed flower. Floret morphology, including lemma surface,...
- Morphotype
- A phytolith shape class defined by the geometry of the silica body: bilobate, cross-shaped, saddle-shaped, elongate, dendritic, and so on. Individual morphotypes...
- Phytolith
- Opaline silica body precipitated in or between plant cells during growth. Grass phytoliths are produced in high quantities and persist in soil...
- Subfamilies Panicoideae and Chloridoideae
- Two of the major grass subfamilies. Panicoideae (warm-season C4 grasses of humid tropics and subtropics) are characterised by bilobate and cross-shaped phytoliths....