Botanical Glossary

68 terms across 3 categories

Ecology

allelopathic

Producing biochemical compounds that inhibit the germination or growth of neighbouring plants. A competitive strategy used by some species to suppress rivals.

A plant that grows on another plant for physical support without parasitizing it. Epiphytes obtain moisture and nutrients from air, rain, and surface debris. Common examples include orchids, bromeliads, and many ferns.

mycorrhizal

Relating to mycorrhizae: symbiotic associations between plant roots and fungi. The fungi extend the root system, improving water and nutrient uptake in exchange for carbohydrates from the plant.

myrmecochorous

Dispersed by ants. Seeds of myrmecochorous plants bear a lipid-rich appendage (elaiosome) that attracts ants, which carry the seeds to their nests, eat the elaiosome, and discard the seed in nutrient-rich waste.

Morphology

achene

A small, dry, one-seeded fruit that does not open at maturity. The seed coat is separate from the fruit wall. Sunflower 'seeds' are technically achenes.

acuminate

Tapering to a long, narrow point, typically referring to a leaf tip. The sides of the tip are concave, creating a drawn-out point.

alternate

A leaf arrangement where one leaf emerges per node, alternating sides along the stem. The most common leaf arrangement in flowering plants.

annual

A plant that completes its entire life cycle — germination, flowering, seed production, and death — within a single growing season.

axillary

Located in or arising from an axil — the angle between a leaf or branch and the stem from which it grows. Axillary buds develop into lateral branches or flowers.

basal

Located at or arising from the base of a plant or structure. Basal leaves grow from the base of the stem at ground level.

berry

A fleshy fruit produced from a single ovary, with seeds embedded in the flesh. Botanically includes tomatoes, grapes, and blueberries, but not strawberries or raspberries.

biennial

A plant that takes two years to complete its life cycle. Typically forms a basal rosette in the first year, then bolts, flowers, sets seed, and dies in the second year.

bract

A modified leaf associated with a flower or inflorescence, often differing in size, shape, or colour from ordinary leaves. Some bracts are showy and petal-like (e.g., dogwood).

calyx

The collective term for all the sepals of a flower, forming the outermost protective whorl. The calyx encloses and protects the developing bud.

capsule

A dry fruit that splits open at maturity to release seeds, formed from two or more fused carpels. Opens by pores, slits, or separating segments.

cauline

Of or pertaining to the stem. Cauline leaves grow along the stem, as opposed to basal leaves which arise at ground level.

clasping

A sessile leaf base that partially or fully wraps around the stem. The leaf appears to hug or clasp the stem at its point of attachment.

cordate

Heart-shaped, typically referring to a leaf base with two rounded lobes where the petiole attaches. From Latin cor (heart).

corolla

The collective term for all the petals of a flower, forming the inner whorl of the perianth. The corolla may be composed of separate petals (polypetalous) or fused petals (sympetalous), and its shape, color, and structure are key features for plant identification.

crenate

A leaf margin with rounded teeth or scalloped edges. Distinguished from serrate (sharp teeth) and dentate (outward-pointing teeth).

cyme

A determinate inflorescence where the central or terminal flower opens first, followed by lateral flowers. Branching is typically forked. Contrast with raceme, which blooms from bottom to top.

cypsela

A small, dry, single-seeded fruit characteristic of the Asteraceae family, formed from an inferior ovary. Unlike a true achene (derived from a superior ovary), the cypsela incorporates tissues from the surrounding floral parts. Often topped by a pappus for wind dispersal.

deciduous

Shedding leaves seasonally, typically in autumn. Deciduous trees drop all their leaves before winter dormancy and regrow them in spring.

dentate

A leaf margin with outward-pointing teeth perpendicular to the edge. Distinguished from serrate (forward-pointing teeth) and crenate (rounded teeth).

drupe

A fleshy fruit with a hard stony pit (endocarp) enclosing a single seed. Cherries, peaches, plums, and poison ivy berries are all drupes.

entire

A leaf margin that is smooth and continuous, with no teeth, lobes, or indentations.

evergreen

Retaining green leaves throughout the year, with old leaves shed gradually as new ones grow. Includes conifers, hollies, and many tropical trees. Contrast with deciduous.

glaucous

Covered with a waxy, bluish-white or grey-green bloom that can be rubbed off. Often seen on leaves, stems, and fruits (e.g., blueberries, cabbage leaves).

inflorescence

The complete flower cluster of a plant, including its arrangement, stalks, and bracts. Common types include racemes, cymes, umbels, panicles, and spikes.

lanceolate

Lance-shaped: much longer than wide, broadest near the base and tapering to a pointed tip. A common leaf shape description.

ligulate

Strap-shaped or tongue-shaped; having a flat, elongated form resembling a strap. Often used to describe ray florets in the Asteraceae family, where the fused petals form a flat, tongue-like extension.

lobed

Having rounded or pointed projections (lobes) separated by indentations (sinuses) that do not reach the midrib. Common in maple and oak leaves.

opposite

A leaf arrangement where two leaves emerge from the same node on opposite sides of the stem. Contrast with alternate and whorled.

ovary

The enlarged basal part of the pistil that contains the ovules. After fertilization, the ovary develops into the fruit.

palmate

A leaf shape or compound leaf arrangement where lobes or leaflets radiate from a single point, like fingers from a palm. Maple leaves are palmately lobed.

panicle

A branched inflorescence in which each branch bears a raceme of flowers. A compound raceme, typically pyramidal in outline and loosely branched.

pappus

A modified calyx in the Asteraceae family, forming a tuft of hairs, bristles, or scales atop the cypsela (fruit). The pappus aids in wind dispersal, as seen in the familiar 'parachute' of dandelion seeds.

pedicel

The stalk that attaches an individual flower to the main stem or inflorescence axis. Distinguished from a peduncle, which is the main stalk supporting an entire inflorescence.

perennial

A plant that lives for more than two years, typically flowering and setting seed each year. May die back to the roots in winter (herbaceous perennial) or retain woody stems (woody perennial).

petiole

The stalk that connects a leaf blade to the stem. Leaves without petioles are called sessile.

pinnate

A compound leaf arrangement where leaflets are arranged on opposite sides of a central axis (rachis), resembling a feather. Bipinnate leaves are twice divided.

pubescent

Covered with short, soft, downy hairs. A common surface texture on leaves, stems, and young shoots.

raceme

An unbranched, elongated inflorescence in which flowers are attached by short stalks (pedicels) along a central axis, typically blooming from bottom to top.

rachis

The main axis of a compound leaf or fern frond, from which the leaflets or pinnae arise. An extension of the petiole.

rhizome

A horizontal underground stem that sends out roots and shoots from its nodes. Rhizomes allow plants to spread vegetatively and store energy for regrowth.

rosette

A circular cluster of leaves radiating from a central point at or near ground level. Common in first-year biennials and some perennials.

sepal

One of the individual leaf-like parts of the calyx, the outermost whorl of a flower. Sepals are typically green and protect the flower bud before it opens.

serrate

Having a leaf margin with sharp, forward-pointing teeth like a saw. Doubly serrate margins have large teeth bearing smaller teeth.

sessile

Attached directly to the stem without a stalk. A sessile leaf lacks a petiole; a sessile flower lacks a pedicel.

silique

A long, narrow, dry seed pod characteristic of the mustard family (Brassicaceae). It splits open along two seams to release seeds, and is typically more than three times as long as wide.

spadix

A thick, fleshy spike bearing tiny flowers, typically enclosed or subtended by a spathe. Characteristic of the arum family (Araceae), as in jack-in-the-pulpit.

spathe

A large bract or pair of bracts that encloses or subtends a spadix or other inflorescence. Often showy and colourful, as in calla lilies and jack-in-the-pulpit.

spatulate

Shaped like a spatula: broad and rounded at the tip, tapering to a narrow base. Used to describe leaf or petal shape.

stamen

The male reproductive organ of a flower, consisting of a filament (stalk) topped by an anther that produces pollen.

succulent

Having thick, fleshy tissues adapted for water storage. Succulent leaves, stems, or roots allow plants to survive in arid or nutrient-poor conditions.

taproot

A large, dominant central root that grows vertically downward, from which smaller lateral roots branch. Carrots and dandelions have prominent taproots.

ternate

Divided into three parts or arranged in groups of three. A ternately compound leaf has leaflets arranged in threes, and may be further subdivided (2-3 times ternately compound).

thallus

A plant body that is not differentiated into distinct stems, leaves, and roots. Found in algae, liverworts, and some aquatic plants.

trifoliate

Having three leaflets, as in clover or poison ivy. A compound leaf divided into exactly three parts.

umbel

An inflorescence in which flower stalks (pedicels) of roughly equal length radiate from a common point, like the ribs of an umbrella. Characteristic of the carrot family (Apiaceae).

undulate

A leaf margin or surface with a wavy, gently rolling pattern. The waves occur in a vertical plane, perpendicular to the leaf surface.

whorled

A leaf arrangement where three or more leaves emerge from the same node, encircling the stem. Less common than alternate or opposite arrangements.