Grass morphology

Yes – grasses (family Poaceae) are structured a bit differently from most flowering plants. Below is a breakdown of the main vegetative (non-flowering) and reproductive (flowering) parts of a grass plant, with definitions.

🌱 Vegetative parts (non-flowering structures)

1. Roots – fibrous root system, anchoring the plant and absorbing water and nutrients.

2. Culm (stem) – the main upright stem of the grass, usually jointed with nodes and internodes.
   
   

   • Node – the solid joint on the stem where leaves and tillers arise.

   • Internode – the hollow or pithy section between nodes.

3. 
   

4. Leaf sheath – the tubular lower part of the leaf that wraps around the stem.

5. Leaf blade – the flat (sometimes rolled), photosynthetic part of the leaf extending from the sheath.

6. Ligule – a thin, often membranous or hairy structure at the junction of the leaf sheath and blade, inside the leaf.

7. Auricles – small ear-like projections at the base of the blade (present in some species, absent in others).

8. Collar – the outer zone where the blade and sheath meet; often used in grass ID.

9. Tillers – secondary shoots that arise from the base of the plant, helping it spread and form tufts.

10. Rhizomes – underground horizontal stems in some grasses, enabling spreading.

11. Stolons – above-ground creeping stems (in species like Couch grass).

🌾 Reproductive parts (inflorescence and flowers)

1. Inflorescence – the flowering head, which may be a spike, raceme, or panicle.

2. Spikelet – the basic flowering unit of grasses, made of glumes and florets.

   • Glumes – two sterile bracts at the base of each spikelet.

   • Rachilla – the small axis within the spikelet that bears florets.

3. Floret – the individual grass flower unit, enclosed by two bracts:

   • Lemma – the outer bract of the floret.

   • Palea – the inner bract of the floret.

4. Lodicules – tiny, scale-like structures at the base of the floret that swell to open the floret for pollination.

5. Stamens – the male organs; usually 3, with long dangling anthers that shed pollen.

6. Ovary – the female organ, with a single ovule inside.

7. Styles & Stigmas – usually 2 feathery stigmas, which catch airborne pollen.

8. Grain (caryopsis) – the fruit of grasses; a dry, one-seeded fruit with the seed coat fused to the ovary wall (e.g., wheat grain).