Summary of Botanical Terminology and Grass Morphology
Botanical Terminology and Grass Morphology Guide for Students
Introduction
Plant morphological terminology encompasses the terms used to describe plant forms, textures, and structures, especially in vascular plants and grasses. This material presents clear definitions, comparisons, and practical examples for university-level botany or agronomy students.
Why is it important?
- It allows for precise description and comparison of species.
- It facilitates taxonomic identification and scientific communication.
- It is essential in herbarium work, phytosociology, and crop improvement.
Definition: Plant morphological terminology is the set of technical terms used to describe the form, arrangement, and texture of plant organs such as leaves, inflorescences, florets, and sheaths.
Leaf Structures and Related Features
Basic Parts
- Blade (leaf-blade): the expanded, photosynthetic part.
- Sheath (leaf-sheath): a basal enclosure that, in many grasses, is tubular for much of its length.
- Apex: the uppermost tip of the blade or a lemma.
Definition: Tubular leaf sheaths are "leaf sheaths that form a tube for most of their length."
Terms for Shape and Margin
- Acuminate: ending in a long, narrow point.
- Attenuate: an apex that gradually tapers.
- Lanceolate: lance-shaped, longer than wide.
- Obtuse: a rounded or slightly pointed apex.
Definition: Acuminate indicates a long, pointed apex; attenuate indicates a gradually tapering tip.
Texture and Covering
- Glabrous: hairless.
- Puberulous: covered with short or fine hairs.
- Hispidulous: covered with short, stiff hairs.
- Scabrous and Scaberulous: rough; scaberulous is slightly rough.
- Glaucous: with a waxy layer that gives a greenish or bluish tint.
Definition: Glabrous means the absence of hairs on the surface; puberulous indicates short, fine hairs.
Inflorescence and Spikelet Terminology (Grasses)
- Spikelet: the basic unit of a grass inflorescence, made up of glumes and florets.
- Glume: a basal bract of the spikelet; it can be persistent or chartaceous.
- Lemma and Palea: parts that enclose each floret.
- Florets: individual flowers within the spikelet.
Definition: A spikelet is the unit of a grass inflorescence that contains one or more florets, protected by glumes.
Characteristics of Glumes and Lemmas
- Persistent Glumes: remain on the spikelet after dispersal.
- Lower glume lateral veins absent or obscure.
- Chartaceous: firm and flexible texture; Membranous: translucent and thin.
- Dentate Apex: a toothed edge on the lemma.
- 2-fid: divided into two lobes or points.
Comparative Table: Glume/Lemma Texture
| Term | Texture / Appearance | Practical Example |
|---|---|---|
| Chartaceous | Firm and flexible | Glumes that retain shape after drying |
| Membranous | Thin and translucent | Awns or thin margins |
| Glaucous | Waxy layer | Young Poa or Festuca leaves |
| Scabrous | Rough surface | Margin rough to the touch |
Growth Forms and Arrangement
- Mat forming: a plant that grows by spreading over the ground, forming a dense cover.
- Caespitose: grows in dense tufts or clumps.
- Innovations: new shoots that arise from the base of the plant.
- Whorls: an arrangement in a circle around an axis.
Definition: Caespitose refers to plants that form dense groupings or tufts from their base.
Inflorescence Characteristics and Disarticulation
- Panicle branches: branches that bear spikelets.
- Disarticulating below each fertile floret: a separation mechanism for dispersal.
- Barren: lacking a rachilla or without fertile development.
- Length of spikelet: a quantifiable trait in mm, useful for identification.
Definition: Disarticulation below the fertile floret indicates that the spikelet separates at that point to facilitate dispersal.
Other Useful Mor
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Plant Morphology Terminology
Klíčové pojmy: Spikelet: basic inflorescence unit in grasses, Glume: basal bract; can be persistent or cartilaginous, Glabrous vs. puberulent: absence or presence of short hairs, Mat-forming vs. cespitose: creeping growth vs. tufted growth, Acuminate and attenuate: types of pointed apex, Disarticulation: separation of spikelets for dispersal, Keel: prominent nerve or crest on floral organs, Membranous vs. cartilaginous: fine vs. firm textures, Hyaline: translucent and thin tissue, Dentate, truncate, obtuse: forms of apices and margins