Botanical Glossary
79 terms across 4 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.
epiphyte
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.
hemiepiphyte
A plant that spends only part of its life cycle as an epiphyte. Primary hemiepiphytes germinate in the canopy and later send roots to the ground; secondary hemiepiphytes begin rooted in soil, climb a host tree, and may eventually lose their ground connection.
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.
nitrogen fixation
The biological conversion of atmospheric nitrogen gas (N₂) into ammonia (NH₃) by symbiotic bacteria (Rhizobium and relatives) housed in root nodules. This makes nitrogen available to the plant and enriches the surrounding soil. The hallmark ecological trait of most Fabaceae species.
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.
aerial root
A root that grows from a stem or branch above the soil surface. Aerial roots may serve to anchor climbing plants to supports, absorb moisture from the air, or reach the ground to provide additional water and nutrient uptake. Common in aroids, orchids, and tropical vines.
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.
corymb
A flat-topped or convex flower cluster (inflorescence) in which the outer flower stalks (pedicels) are longer than the inner ones, so that all flowers reach approximately the same level. Differs from an umbel in that the pedicels arise at different points along the stem rather than from a single point.
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.
fenestration
Natural holes, perforations, or window-like openings in a leaf blade. Thought to optimize light capture by allowing sunlight to reach lower leaves, reduce wind resistance, or improve thermoregulation. Most famously seen in Monstera species.
follicle
A dry, dehiscent fruit derived from a single carpel that splits open along one seam (suture) to release seeds. Often found in clusters (aggregate of follicles). Common in Ranunculaceae, Rosaceae (Spiraea), and Apocynaceae (milkweed).
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.
legume
A dry, dehiscent fruit (pod) derived from a single carpel that splits open along two seams — the defining fruit type of the family Fabaceae. Also used informally to refer to any plant in Fabaceae or its edible seeds (beans, peas, lentils).
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.
papilionaceous
Butterfly-shaped; describing the characteristic flower form of subfamily Papilionoideae (Fabaceae), with five petals arranged as a broad upper standard (banner), two lateral wings, and two lower petals fused into a keel that encloses the stamens and pistil.
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.
stipule
A small, usually paired appendage found at the base of a leaf petiole where it attaches to the stem. Stipules vary widely in form: leaf-like, scale-like, spiny (as in Robinia), or fused to the petiole (as in Rosaceae). Their presence or absence is an important diagnostic character.
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.
Phenology
Reproduction
apomixis
Asexual reproduction through seeds, in which embryos develop without fertilization. The resulting offspring are genetically identical clones of the mother plant. Common in some grasses, dandelions, and hawkweeds.
dioecious
Having male and female flowers on separate individual plants. Both a male and a female plant are needed for seed production. Contrast with monoecious.
gametophyte
The haploid, gamete-producing phase in the life cycle of plants that exhibit alternation of generations. In ferns, the gametophyte is a small, heart-shaped prothallus; in flowering plants, it is reduced to structures within the pollen and ovule.
monoecious
Having separate male and female flowers on the same individual plant. A single plant can produce seed on its own. Contrast with dioecious.
pollen
Fine powdery grains produced by the anthers of seed plants, containing the male gametophyte. Transferred to the stigma (pollination) to enable fertilization.
sporophyte
The diploid, spore-producing phase in the life cycle of plants that exhibit alternation of generations. In ferns and seed plants, the sporophyte is the dominant, visible plant body.
turion
A specialized, compact vegetative bud produced by aquatic plants for asexual reproduction and overwintering. Turions detach from the parent plant, sink to the sediment, remain dormant through unfavorable conditions, and germinate when conditions improve — functioning as a survival and dispersal strategy.