plant glossary

Parts of a leaf

leaf (leaves): The major parts of a leaf are the blade, petiole, and stipule. The petiole and stipule may each be present or not, while the blade may be very small or needle-like. [Jepson]

blade: The expanded portion of a leaf where photosynthesis primarily occurs. May be simple or compound with multiple leaflets. [Jepson]
petiole: The stalk of a leaf. [Jepson]
stipule: Extension at the base of the petiole. [figure] [Jepson]

leaflet: A division of a compound leaf (which may itself be further compound). Can be distinguished from a leaf by the lack of any structures in its axil other than more leaflets or occasionally stipules. [Jepson]

3-D shapes (e.g. for an involucre)

All involucre shapes may be flared at the tip or not, which is independent of the shape listed below.

bell-shaped: Rapidly widening at the base, then slowly expanding toward the tip. [Jepson]
cylindric: Significantly longer than wide with parallel sides. [Jepson]
ovoid: Egg shaped; widest between the middle and the base. [Jepson]
obovoid: Egg shaped; widest between the middle and the tip.
rotate: Saucer-shaped. For a corolla, generally means a fused base with little or no tube and spreading limbs. [Jepson]
urn-shaped: Rapidly widening at the base, then narrowed toward the tip. [Jepson]

2-D shapes (e.g. for a leaf)

Particularly for leaves, the base of the blade may taper to the petiole regardless of the shape description. [example leaf shapes]

awl-like: Long, narrow, and pointed, but slightly wider at the base, so not quite linear. [Jepson]
cordate: Shaped like a heart in a deck of cards (with tip outward, lobes at the base). [example] [Jepson]
elliptic: In the shape of an elongated circle, widest near the middle. Wider than linear. [example] [Jepson]
fan-shaped: [I’m guessing] Expanding from the base to a ± truncate or ragged wide end.
hastate: In the shape of an spearhead, with the two basal lobes spreading ± perpendicular to the axis. Compare sagittate. [Jepson]
lanceolate: Long, somewhat narrow, and tapering to a point at the tip; widest between the middle and the base. [example] [Jepson]
linear: Long and very narrow with ± parallel sides. [example] [Jepson]
oblanceolate: Long, somewhat narrow, and tapering to a point at the tip; widest between the middle and the tip. [example]
oblong: Longer than wide, with ± parallel sides. Wider than linear. [example] [Jepson]
ovate: Egg shaped; widest between the middle and the base. [example] [Jepson]
obovate: Egg shaped; widest between the middle and the tip. [example]
reniform: In the shape of a dented oval, with the petiole connection in the dent. Depending on your source, the distinction from cordate is that the tip of the blade is rounded (instead of pointed) or that the blade base is concave around the petiole attachment (instead of sharply notched). [example] [Jepson]
sagittate: In the shape of an arrowhead, with the two basal lobes draped ± parallel to the axis. Compare hastate. [Jepson]
wedge-shaped: [I’m guessing] Like fan-shaped, but narrower.
spatulate: Broad near the tip and tapering toward the base. Based on the diversity of example images on the web, this term may be less precise than it sounds.

2-D branching organization

palmate: With lobes spreading in a plane from a common point. [Jepson]
palmate-pinnate: 1st-order palmate and 2nd-order pinnate.
pinnate: Refers to a two-dimensional structure with nodes branching to either side of a central axis. Typically refers to lobes or leaflets in a leaf. [Jepson]
odd-pinnate: Pinnate with pairs of lateral branches and one terminal branch.
even-pinnate: Pinnate with pairs of lateral branches but no terminal branch.
N-pinnate: 1-pinnate means that the structure has 1 level of branches arising from a central axis. 2-pinnate means that the branches also have branches, etc.
ternate: With three parts from a common point, or lobed/dissected/compound in three parts. [Jepson]
N-ternate: 1-ternate means that the structure has just 3 parts. 2-ternate means that each of the 3 main parts itself has 3 parts, etc.
N-ternate-pinnate: N-pinnate, with each level of branching being ternate.

Tip shapes

Example drawings are here.

acuminate: A long tip with concave sides meeting at a sharp angle. [Jepson]
acute: A short tip with convex or straight sides meeting at an angle sharper than 90°. [Jepson]
mucronate: A short tip with concave sides meeting at a sharp angle. [Jepson]
obtuse: A short tip with convex or straight sides meeting at an angle blunter than 90°. [Jepson]
tapered: Narrowing gradually to the tip. [Jepson]
truncate: Abruptly narrowed at the tip, as if cut flat. [Jepson]

Border shapes

entire: In one smooth shape; i.e. not toothed, lobed, or compound. [Jepson]

crenate: With shallow, rounded teeth and usually with acute sinuses. Could also be called “scalloped”. [Jepson]

tooth (teeth): A small, roughly triangular projection. See serrate and dentate. Compare lobe. [Jepson]
deltate: Shaped like the Greek letter Δ; an equilateral triangle with corners rounded or not; attached at base. [Jepson]
dentate: With teeth pointing outward. Contrast serrate. [Jepson]
serrate: With teeth pointing tipward. Contrast dentate. [Jepson]
double-serrate: Serrate, with each tooth having smaller serrate teeth on it.

Direction of growth

appressed: Leaning closely against the originating structure, e.g. a leaf appressed to a stem or a hair appressed to a leaf. [Jepson]
ascending: Angled up (but less than erect) or angled in the direction of the main axis (but not nearly parallel to the main axis). [Jepson]
decumbent: Lying on or near the ground but with its tips ascending or erect. Compare to prostrate. [Jepson]
erect: Pointing ± straight up or parallel to the main axis. [Jepson]
nodding: Partially drooping, between pendent and spreading. [Jepson]
pendent: Drooping or hanging ± straight down. [Jepson]
prostrate: Lying entirely on the ground. Compare to decumbent. [Jepson]
spreading: Nearly horizontal or perpendicular to the main axis. [Jepson]

Relative position

abaxial: The surface further from the stem when upright. E.g. the lower surface of a leaf or the outer surface of a petal. [Jepson]
adaxial: The surface closer to the stem when upright. E.g. the upper surface of a leaf or the inner surface of a petal. [Jepson]
basal: Positioned at the base. Most commonly refers to leaves growing at the base of the stem. Contrast cauline as well as lateral and terminal. [Jepson]
cauline: Growing along a plant’s stem. Most commonly refers to leaves. Contrast basal. [Jepson]
distal: Closer to the tip and farther away from the base of a structure. The structure is often implied; e.g. a distal leaf grows at the end of the plant furthest from the base. Contrast proximal. [Jepson]
exceeds: Reaches further distally (than the compared structure), either because it is longer or is positioned further distally.
lateral: Relative to the sides of a structure (neither distal nor proximal). May refer to the sides of the described structure or of an implied structure, e.g. lateral lobes. Contrast basal, terminal. [Jepson]
proximal: Closer to the base and farther from the tip of a structure. The structure is often implied; e.g. a proximal leaf grows close to the base of the whole plant. Contrast distal. [Jepson]
subtend: Growing immediately proximal to the compared structure. [Jepson]
terminal: At the tip of a structure, e.g. the most distal segment of a compound or lobed leaf. Contrast lateral, basal. [Jepson]

Sexual capability

female: A reproductive structure capable of being fertilized by a male gamete.
male: A reproductive structure that produces gametes capable of fertizing a female body.
bisexual: A plant that has both male and female parts (e.g. both staminate and pistillate flowers), in the same structure or not. [Jepson]
dioecious: A plant that has only either male or female reproductive structures (e.g. staminate or pistillate flowers), never both on the same plant. [Jepson]
monoecious: A plant that has both male and female structures (e.g. flowers), but never both male and female parts in the same structure. [Jepson]

Miscellaneous terms

alternate: Arranged singly along an axis. Not all on the same side, but not necessarily on alternating sides, either. E.g. may be spirally arranged. See opposite, whorl. [Jepson]
annual: Lives for one year or less, generally without forming any woody parts. [Jepson]
axil: The distal, adaxial angle between a main axis (e.g. a stem) and an appendage (e.g. a branch or leaf). [Jepson]
axis (axes): The direction of growth, or the structure that grows along the axis (e.g. a stem). [Jepson]
biennial: Lives for only two years, generally flowering only in the second year. Non-woody. [Jepson]
bud: A new shoot, usually covered with bud scales. [Jepson, flower glossary]
caudex (caudices): Short stem below ground level. [Jepson]
clasping: Mostly surrounding, e.g. a leaf blade or winged petiole clasping the stem. See also decurrent.
compound: Generally, composed of multiple parts. Opposite of simple.
leaf: divided into distinct leaflets connected by an axis but no blade material.
umbel: an umbel of umbels
[Jepson]
deciduous: Having leaves that fall off seasonally. If another deciduous part is named, that part falls off naturally before other parts or is easily knocked off. [Jepson]
decurrent: The leaf blade extends onto the stem as a short wing. [Jepson]
dehiscent: Splitting along a seam. [Jepson]
dissected: Cut deeply, but not fully divided. [Jepson]
divided: Divided into distinct parts, e.g. a compound leaf.
exserted: Protruding more than surrounding structures. [Jepson]
fertile: Capable of germinating or causing germination, e.g. a stamen that can make viable pollen. Not sterile. [Jepson]
fleshy: Soft and thick. Succulent. [Jepson]
free: Growing separately from equivalent structures at the same level, e.g. sepals in the calyx. Compare fused. [Jepson]
fuse: Equivalent structures at the same level that have grown together (more than just touching). Compare free.
gland: A small sphere on the surface of a plant or at the tip of a hair that excretes a generally sticky material. [Jepson]
glandular-hairy: Having gland-tipped hairs.
glaucous: Covered with the appearance of a whitish powder. [Jepson]
habit: Overall aboveground plant shape and general direction of growth. [Jepson]
herb: Plant without any woody parts. [Jepson]
internode: Stem segment between nodes. [Jepson]
lobe: An protrusion from a larger body, otherwise undifferentiated from the main body. E.g. a corolla lobe is the free part of a petal. [Jepson, blue-eyed marys]
mucro: An abrupt, short, narrow tip/projection. [Jepson]
node: A position on a stem from which grow structures such as leaves, flowers, or stems. See also internode. [Jepson]
open: Not densely clustered, i.e. with parts that are spread out from each other. [Jepson, flower glossary]
opposite: Arranged in clusters of 2 with each pair on opposing sides of an axis. See alternate, whorl. [Jepson]
papillate: Has a surface with small protuberances, e.g. like the surface of your tongue. [Jepson]
perennial: Lives for more than two years. May be woody or non-woody. [Jepson]
perennial herb: Non-woody plant that lives for more than two years. Is generally more robust than an annual, but there is no general way to distinguish a perennial herb from an annual unless you’re already familiar with the ranges of variation in the plants in question.
persistent: Not deciduous. [Jepson]
plumose: Having many feathery tufts in a 3-D arrangement around an axis. [Jepson]
primary leaf: The first one or two leaves of a sprouting monocot or dicot. These are the most proximal leaves. For dicots, the two leaves are opposite.
ray: One of 3+ radiating axes, e.g. a primary branch in a compound umbel. [Jepson, sunflower glossary]
recurved: Gradually curved backward. Contrast reflexed. [Jepson]
reflexed: Abruptly bent somewhat or entirely backward. Opposite of erect or ascending. Contrast recurved. [Jepson]
reticulate: Wrinkled. (Not just ribbed.)
rib: A raised band of material, e.g. covering a vein. [Jepson]
rosette: Basal leaves growing radially around the stem. [example] [Jepson]
scale: Flat, membranous structure. [Jepson, conifer glossary, sunflower glossary]
scarious: Membranous. [Jepson]
seed: A fetrilized ovule capable of sprouting a new plant. Often encapsulated in a fruit which provides energy, protection, and/or a means to dispersal for the seed. [figure] [Jepson]
segment: The smallest division of a compound/dissected leaf. [Jepson]
series: A group of similar structures in a row, circle, or whorl. If there are multiple series of the same kind of structure, then each series differs in size or shape. [Jepson]
sessile: Unstalked. E.g. no petiole, peduncle, or pedicel. [Jepson]
sheath: Surrounding tubular structure, e.g. a grass leaf base. [Jepson]
shrub: Woody plant, shorter than a tree, generally with many branches from the base. Compare subshrub. [Jepson]
simple: Generally, composed of a single part; undivided; unbranched. Opposite of compound.
Leaf: composed of a single part (which may be lobed or dissected), not divided into distinct leaflets separated from each other.
[Jepson]
sinus: The gap between adjacent lobes or teeth. [Jepson]
stellate: With 3+ branches radiating from a common point. (Usually used to describe hair.) [Jepson]
stem: The generally above-ground structure of a plant supporting leaves, flowers, etc. Depending on context, “stem” may include branches or only the primary axis. [Jepson]
sterile: Incapable of germinating or causing germination, e.g. branches without flowers. Not fertile. [Jepson]
subsessile: Almost sessile. E.g. very short petiole, peduncle, or pedicel.
subshrub: Similar to a shrub, but with only the proximal stems woody. The distal stems are non-woody (or are at least significantly less woody). [Jepson]
succulent: Composed of fleshy tissue that conserves water.
taproot: Primary root growing straight down, tapering at the end, with smaller lateral branches. [Jepson]
tree: Woody plant, taller than a shrub, generally with one central trunk from which branches spring higher up. [Jepson]
tubercle: A small hemispherical projection. [Jepson]
twig: The ultimate branch segment of a woody plant. [Jepson]
ultimate: The smallest division of a compound/dissected leaf or the final segments of a branching stem. [Jepson]
vegetative: Without reproductive structures (flowers, fruit, cones, etc.)
vein: A visible vascular bundle used for transport of material through the plant. Appears as a line of a different color shade or as a raised rib. [Jepson]
waif: A plant that has spread with human assistance but cannot reproduce or spread further on its own. Will eventually die out with no further assistance. [Jepson]
whorl: A cluster of 3 or more (e.g. flowers) with each whorl generally surrounding an axis and multiple whorls interspersed along the axis. See alternate, opposite. [Jepson]
wing: A thin, flat extension of a surface. See also decurrent. [Jepson, legume glossary]
winged petiole: A petiole with a wing on each side which is distinct but significantly narrower than the leaf blade.