Cluster

Cluster (Synonym: clump) [ Botany ]
Adjective: clustered or clustery

Dictionary of botanic terminology - index of names


	A clump or cluster is a mass; a lump, a thick group of something like growing plants, as of trees, bushes or basal shoots.

(For example a clump of moss)

To cluster (Intransitive and transitive verb: past clustered, past participle clustered, present participle clustering, 3rd person present singular clusters)


	To gather, to combine things into mass or form lumps or small groupings of something.

Clustering habit [ Habit of growth - Botany ]
Synonym: Clumping habit.

	A clumping or clustering habit is a vegetative features that describe a plant forming a tight or open clumps or groups of shoots.

(Spine) cluster [ Botany ]

A (spine) cluster is a group of spine, arising from a formation called an areole.

Spine clusters are typical structures characteristic of the Cactaceae family, they develop from a meristematic growth centre called the areole which is positioned on the tubercles (raised , domelike or elongate areas along the stem) or on the ribs. Each spine cluster (corresponding to an areole) may contains central and radial spines and also glochids, hairs, leafs or glands.
	Unlike other flowering plants that are principally identified by flower and fruit morphology, cacti are identified primarily by their spine clusters morphology.
In plants of the subfamily Opuntioideae the cluster of spines arise in the axil of a small caducous (early deciduous) leaf.

Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994