Ohio State University Extension Bulletin 866-98

Identifying Noxious Weeds of Ohio

Bulletin 866-98


Glossary of Plant Terminology

alternate leaves - adjacent leaves arranged on alternating sides of stem, not opposing.

annual - a plant that flowers, sets seed, and dies within one year.

basal rosette - a low cluster of leaves; a growth habit typical of biennials in the first year.

biennial - a plant that lives for two years, producing flowers and seed the second year.

blade - a linear, parallel-veined leaf, typical of a grass.

brace roots - supporting roots that sprout from the base of stems.

bracts - modified leaves that may encircle or envelope flowers; bracts may be colored resembling petals, or may be green and scalelike.

compound leaf - a leaf divided into leaflets, but considered one unit.

fibrous roots - a fine, branched root system with many root hairs and lateral roots, lacking a taproot.

glabrous - hairless.

inflorescence - a floral structure.

lanceolate - long, spear or lance-shaped.

leaf margins - leaf edges.

leaflet - individual leaflike portions of a compound leaf; e.g., a rose leaf may have 3, 5 or 7 leaflets.

midvein - the middle vein running through the center of a leaf.

node - the portion of stem where the leaves are attached.

opposite leaves - leaves arranged in pairs on opposite sides of the stem.

panicle - a branched floral structure.

pappus - a cluster of seeds with tiny tufts of "hair" attached (e.g., dandelion)

perennial - a plant that may live many years, growing each year from stored energy reserves in roots or woody structures.

petiole - the stem-like structure attaching a leaf to the branch.

pinnately compound leaf - leaflets arranged along a single axis much like a feather.

pubescent - covered with small hairs

rhizomes - underground, creeping stems; capable of forming new plants.

simple - A leaf lacking any subdivisions (leaflets). The opposite of compound.

spike - a long slender floral structure with individual flowers directly attached to the stalk.

stipules - leaflike structures attached at the base of the leaf.

taproot - a single, thick, fleshy root. (e.g. carrot).

terminal - located at the top

umbel - a branched floral structure resembling an (upside-down) umbrella.

whorled leaves - three or more leaves arising from a single node.


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