GLOSSARY OF TAXONOMIC TERMS
From: Amer Taxonom Society?
GLOSSARY OF TAXONOMIC TERMS
Commonly Employed in the Identification of Woody Plants
Achene - A dry indehiscent one-seeded fruit. Ex: fr. of
members of the Compositae.
Acuminate - Having an apex whose sides are gradually
concave and tapering to a point.
Acute - Having an apex whose sides are straight and taper
to a point.
Adventitious - Arising from an unusual or irregular position.
Aggregate flower - A flower heaped or crowded into a dense
cluster.
Aggregate fruit - One formed by the coherence or the connation
of pistils that were distinct in the flower
(as in Rubus) when the pistils of separate
flowers (as in mulberry) make up the fr. it is
designated as a multiple fruit.
Alternate - An arrangement of leaves or other parts not
opposite or whorled; parts situated one at a
node, as leaves on a stem: like parts
succeeding each other singly with a common
structure.
Ament - See catkin.
Apetalous - Without petals. Ex: fls. of grasses.
Apex - The tip or terminal end.
Apical - Describes the apex or tip.
Apiculate - Ending abruptly in a short pointed tip.
Appressed - Pressed close to the stem, not spreading.
Auriculate - Bearing ear-like appendages, as the
projections of some leaf and petal bases.
Berry - A fleshy indehiscent pulpy multi-seeded fr.
resulting from a single pistil. Ex: tomato.
Bipinnate - Twice pinnate.
Bloom - A waxy coating found on stems, leaves, flowers and
fruits, usually of a grayish cast and easily
removed.
Boss - A raised usually pointed projection.
Bract - A much-reduced lf., often scale-like and usually
associated with a fl. or infl.
Broad-elliptic - Wider than elliptic.
Broad-ovate - Wider than ovate.
Bud scale - A modified leaf or stipule (there may be one,
a few, or many) protective of the embryonic
tissue of the bud.
Bud scale scar - The mark left by the sloughing off of the bud
scale.
Bundle scar - Seen in the leaf scar, the broken ends of the
woody vascular strands that connected the leaf
and the stem.
Calyx - The outer set of perianth segments or floral
envelope of a flower, usually green in color and
smaller than the inner set.
Capsule - A dry dehiscent fruit produced from a compound
pistil. Ex: fruit of a tobacco, Catalpa, Dianthus.
Catkin - A spike-like infl. comprised of scaly bracts
subtending unisexual fls., often somewhat flexuous
and pendulous but not necessarily so. Ex: infl. of
willows (Salix) and poplars (Populus).
Chambered - Of pith, divided into empty horizontal
chambers by cross partitions.
Ciliate - Marginally fringed with hairs, often minutely so
and then termed "ciliolate."
Clone - A group of plants derived vegetatively from one
parent plant, identical to each other and to the
parent.
Coarse texture - Consisting of large or rough parts.
Compound leaf - A leaf of two or more leaflets.
Cone - A coniferous fruit, having a number of woody,
leathery, or fleshy scales, each bearing one or
more seeds, and attached to a central axis.
Conical - Cone shaped, as the young form of many spruces.
Coniferous - Cone, bearing.
Cordate - Heart-shaped, with a sinus and rounded lobes.
Corymb - A more or less flat-topped indeterminate infl.
whose outer fls. open first. Ex: Viburnum, some
verbenas.
Crenate - Rounded teeth on mgn. Ex: Ivs. of some Coleus.
Crenulate - Having very small rounded teeth.
Cultivar - A cultivated variety.
Cuneate - Wedge-shaped with essentially straight sides, the
structure attached at the narrow end.
Cyme - A more or less flat-topped determinate infl. whose
outer fls. open last. Ex: elderberry (Sambucus).
Dehiscent - Splitting open. The term is commonly applied
to anthers or seed pods.
Dentate - Having marginal teeth whose apices are
perpendicular to the margin and do not point
forward.
Dicot - Angiospermous plant having two cotyledons.
Dimorphic - Having two forms.
Dioecious - Having unisexual fls., each sex confined to a
separate plant, said of species.
Double serrate - Serrations bearing minute teeth on margins.
Drupe - A fleshy indehiscent fr. whose seed is enclosed in
a stony endorcarp. Ex: date, cherry.
Ellipsoid - Three dimensional shape of ellipse, football
shaped.
Elliptic-oblong - A shape between the two forms.
Elliptical - Having the outline of an ellipse, broadest at
middle and narrower at each end.
Emariginate - With a shallow notch at the apex.
Endocarp - The inner layer of the pericarp.
Entire - Having a margin without teeth or crenations.
Even-pinnate - Results in a lack of the terminal leaflet, since
each one is paired.
Exfoliate - To peel off in shreds or thin layers, as bark
from a tree.
Falcate - Sickle-shaped.
Fascicle - A close cluster. Ex: lvs. of white pine.
Filiform - Long and very slender; thread-like.
Fine texture - Consisting of small rather delicate parts.
Flaking - Shreddy, with shorter fragments.
Follicle - A dry dehiscent fruit opening only along one
suture and the product of a single carpel
(simple ovary). Ex: peony, columbine,
milkweed.
Fruit - Technically a ripened ovary with its adnate parts,
the seed-containing unit characteristic of all
Angiosperms.
Genus - A group of species possessing fundamental traits in
common but differing in other lesser
characteristics.
Glabrous - Not hairy. Note: a glabrous surface need not
be smooth, for it may be bullate or rugose.
Glandular - Bearing glands.
Glaucescent - Slightly glaucous.
Glaucous - Covered with a waxy bloom or whitish material
that rubs off readily. Ex: the bloom on many
sorts of grape.
Globose - Having a round or spherical shape.
Grooved - Marked with long narrow furrows or channels.
Hairy - Pubescent with longer hairs.
Hispid - With stiff or bristly hairs.
Hirsute - Pubescent with coarse or stiff hairs.
Imbricated - Overlapping, as shingles on a roof.
Imperfect - A flower that lacks either stamens or pistils.
Incised - Cut by sharp and irregular incisions more or less
deeply, but intermediate between toothed and lobed.
Indehiscent - Not opening regularly, as a capsule or anther.
Indumentum - With a generally heavy covering of hair: a general
term without precise connotation.
Inferior - Beneath, below; said of an ovary when situated
below the apparent point of attachment of
stamens and perianth.
Involucre - One or more whorls or series of small lvs. or
bracts that are close underneath a fl. or
infl.
Juvenile - An early phase of plant growth, usually
characterized by non-flowering, vigorous
increase in size, and often thorniness.
Lanceolate - Much longer than wide, broadest below the
middle and tapering to the apex.
Lateral bud - A bud borne in the axil of a previous season's
leaf.
Latex - Milky sap.
Leaf scar - The mark remaining after the leaf falls off a
twig.
Lenticel - A small corky spot on young bark made of
loosely packed cells, providing gaseous
exchange between the inner tissues and the
atmosphere.
Linear - Long and very narrow, as in blades of grass.
Lobe - A projecting part or segment of an organ as in a
lobed ovary or stigma; usually a division of a lf.,
calyx, or petals cut to about the middle (i.e.
midway between margin and midrib).
Margin - The edge of a leaf.
Marginal - Pertaining to the margin.
Mature - A later phase of growth characterized by flowering,
fruiting, and a reduced rate of size increase.
Milky sap - Whitish in color, often thicker than water.
Monoecious - A species with unisexual fls., having both
sexes on the same plant. Ex: corn.
Mucro - A short, sharp, abrupt tip.
Mucronate - Abruptly terminated by a mucro.
Multiple buds - A terminal or lateral bud crowded by many
accessory buds.
Naked bud - One without scales.
Native - Inherent and original to an area.
Needle - The slender leaf of many conifers.
Nerve - A slender rib or vein, especially unbranched.
Node - A joint on a stem, represented by point of origin
of a leaf or bud; sometimes represented by a
swollen or constricted ring, or by a distinct leaf
scar.
Nut - A dry, indehiscent, 1-celled, 1-seeded fruit
having a hard and bony mesocarp; the outermost
endocarp may be fibrous or slightly fleshy.
Obscordate - The apex being codate.
Oblanceolate - Inversely lanceolate.
Oblique - Lop-sided, as one side of a leaf base larger, wider
or more rounded than the other.
Oblong - Longer than broad; rectangular; the sides nearly
parallel.
Oblong - Lanceolate: a shape in between the two forms.
Oblong-obovate - A shape in between the two forms.
Obovate - Inversely ovate, broadest above the middle.
Obovoid - Three dimensional shape of obovate, pear shaped.
Obtuse - Rounded, approaching the semi-circular.
Opposite - Two at a node, as leaves.
Orbiculate - Circular or disk-shaped. Ex: leaf of common
nasturtium.
Oval - Twice as long as broad, widest at the middle,
both ends rounded.
Ovate-oblong - A combination of the two forms.
Palmate - Digitate, radiating, fan-like from a common point,
as leaflets of a palmately compound lf. or veins or
palmately-veined lf.
Panicle - An indeterminate infl. whose primary axis bears
branches of pedicelled fls. (at least basally so);
a branching raceme.
Peltate - Having the petiole attached inside the margin, such
a lf. is typically shield-shaped.
Pendulous - More or less hanging or declined.
Pericarp - A term used by some to designate a fruit;
technically, the ovary wall.
Periderm - A protective layer of corky cells.
Petiole - Leaf-stalk.
Petiolule - Leaflet-stalk.
Pilose - Shaggy with soft hairs.
Pinna - The lft. of a compound lf.; of ferns, the primary
division attached to the main rachis; feather-like.
Pinnate - Compounded with the lfts. or segments along each
side of a common axis or rachis; feather-like.
Polygamous - Bearing unisexual and bisexual flowers on the
same plant.
Pome - A type of fleshy fruit represented by the apple,
pear and related genera, resulting from a compound
ovary.
Prickle - An excrescence of bark that is small, weak, and
spine-like.
Pseudo-terminal bud - Seemingly the terminal bud of a twig, but
actually the upper-most lateral bud with
its subtending lf. scar on one side and
the scar of the terminal bud often
visible on opposite side.
Pubescent - Covered with short soft hairs; a general term.
Pyramidal - Broadest at base, tapering apically; pyramid-
shaped.
Raceme - A simple indeterminate inflorescence with
pedicelled flowers.
Rachilla - A diminutive or secondary axis; a branch of a
rachis; the minute axis bearing the individual
florets in grass and sedge spikelets; the
secondary axes of decompound fern fronds.
Rachis - Axis bearing leaflets or the primary axis of an
infl.; the axis bearing pinnae of a fern frond.
Ranked - Foliage is arranged in longitudinal planes around
the stem.
Receptacle - A torus; the distal end of a flower-bearing
axis, usually more or less enlarged,
flattened, or cup-like on which some or all of
the flower parts are borne. Ex: Compositae,
Onagraceae.
Reflexed - Bent abruptly backward or downward.
Reinform - Kidney-shaped.
Resin duct - A lengthwise or transverse canal carrying
resins.
Resinous - Secreting a viscid exudate.
Reticulate - Like a net, the interstices closed.
Rhombic - With four nearly equal sides, but unequal angles,
diamond shaped.
Rugose - Wrinkled, usually covered with wrinkles.
Samara - A dry indehiscent fruit bearing a wing (the wing
may be limb-like or envelop the seed and be wafer-
like). Ex: maple, ash, Ptelea.
Scar - The mark left from a former attachment.
Schizocarp - A dry dehiscent fr. that splits into two
halves. Ex: maple.
Serrate - Saw-toothed, the teeth pointing forward.
Serrulate - Minutely serrate.
Sessile - Without a stalk.
Simple - Said of a lf. when not compound, of an infl. when
unbranched.
Sinuate - With a strongly wavy margin.
Sinus - The space between two lobes, segments, or
divisions; as of Ivs. or perianth parts.
Solitary - Occurring alone, not paired or clustered.
Spatulate - Spoon-shaped.
Species - A natural group of plants composed of similar
individuals which can produce similar offspring;
usually including several minor variations.
Spike - A usually unbranched, elongated, simple,
indeterminate infl. whose fls. are sessile; the
fls. may be congested or remote.
Spikelet - (1) a secondary spike; (2) one part of a
compound infl. which of itself is spicate; (3)
the floral unit, or ultimate cluster, of a
grass infl. comprised of fls. and their
subtending bracts.
Spine - An excrescence of st., strong and sharp-pointed.
Ex: spines of hawthorns.
Squarrose - With branches spreading and recurved at the
ends.
Stalked bud - A bud whose outer scales are attached above
the base of the bud axis.
Stellate - Star-like; stellate hairs having radiating
branches or are separate hairs aggregated in
star-like clusters; hairs once or twice forked
often are treated as stellate.
Stipel - A stipule of a lft.
Stipule - A basal appendage of a petiole, usually one at each
side, often ear-like and sometimes caducous.
Striate - With fine longitudinal lines, channels or ridges.
Strigose - With sharp, stiff, straight and appressed
hairs.
Strobilus - A cone.
Subtend - To stand immediately beneath.
Sympodial - Continuing growth by the development of an
axillary bud and not the terminal bud, season
after season.
Tendril - A modified stem or leaf, usually filiform, branched
or simple, that twines about an object providing
support.
Tepal - A segment of perianth not differentiated into calyx
or corolla. Ex: tulip, magnolia.
Terminal - At the tip or distal end.
Ternate - In threes.
Thorn - A modified twig which has tiny leaf scars and buds;
can be single or branched.
Tomentose - Densely woolly, the hairs soft and matted.
Translucent - Transmitting light but diffuse enough to
distort images.
Trifoliate - Three-leaved. Ex: Trillium.
Truncate - As if cut off at right angles to the primary
axis; a term applicable to bases or apices.
Umbel - An indeterminate infl., usually but not necessarily
flat-topped with the pedicels and peduncles (termed
rays) arising from a common point, resembling the
stays of an umbrella.
Umbo - A conical projection arising from the surface.
Undulate - Wavy, as a leaf margin.
Valvate - (1) dehiscing by valves; (2) meeting by the edges
without overlapping, as lvs. or petals in the bud.
Variegated - Striped, margined or mottled with a color
other than green, where green is normal.
Variety - Subdivision of a species having a distinct though
often inconspicuous difference, and breeding true
to the difference. More generally also refers to
clones.
Vascular bundle - A discrete group of conducting vessels.
Vascular bundle scar - A minute spot within the leaf scar where
the vessels were positioned.
Velutinous - Clothed with velvety indumentum comprised of
erect straight dense moderately firm hairs.
Whorl - Arrangement of three or more structures arising
from a single node.
Woolly - Having long, soft, more or less matted hairs; like
wool.