Glossary for the Key to
The Gymnosperms of the Southeastern U.S.

edited by Stephen M. Seiberling
November 30, 2005

The following glossary contains botanical terms that occur in the Key to the Gymnosperms of the Southeastern U.S. <> along with certain other basic terms that the reader may find helpful for understanding the definitions. A number of the definitions given here apply specifically to the features of the taxa in the key, and are thus more narrow than the range of meanings used more broadly in botanical literature.

The principal source used for each definition is listed in brackets at the end of the entry. Definitions with no source listed were written by the editor.



Acute – Tapering to a pointed apex with more or less straight sides, the sides coming together at an angle of less than 90º. (Compare with obtuse.) [modified from H&H, p. 153]

Alternate – Positioned singly at different heights on the stem; one leaf occurring at each node. (Compare with opposite and whorled.) [modified from L, p. 738]

Angiosperm – Plants that bear their seeds enclosed in an ovary; the flowering plants. (Compare with gymnosperm.)

Anther – The pollen-producing portion of the stamen, typically borne at the tip of a stalk or filament. [modified from Z, p. 358]

Apex – The portion of a plant structure (such as a leaf, bud, stem, etc.) farthest from its point of attachment or uppermost; the tip. (Compare with base.) [modified from H&H, p. 10]

Appressed – Pressed upwardly, close or flat against the bearing structure, thus more or less parallel to it. (Compare with ascending, reflexed and spreading.) [modified from K&P, p. 16]

Armature – Any kind of sharp defense such as thorns, spines, or prickles. [modified from L, p. 739]

Armed – Bearing a hook, prickle or other sharply pointed structure on the end of the cone scale. (Compare with unarmed.)

Ascending – Spreading at the base and then curving upward to an angle of 45º or less relative to the bearing structure. (Compare with appressed, reflexed and spreading.) [modified from K&P, p. 18]

Asymmetric – Not divisible into essentially equal halves along any plane. (Compare with nearly symmetric and symmetric.) [modified from K&P, p. 18]

Awl-shaped – Narrowly triangular and sharply pointed, like an awl. (Compare with linear.) [modified from H&H, p. 150]

Axis – Any relatively long, continuous, supporting structure that typically bears other organs laterally, and represents the main line of growth and/or symmetry; as a stem that bears leaves or branches. [modified from K&P, p. 19 & H&H, p. 13]


Bark – The outermost layer of a woody stem, usually with one or more corky layers that prevent water loss and protect the inner living tissues from mechanical damage. [modified from W&K, p. 587]

Bark plate – A more or less flat section of bark, often separated by furrows or grooves, as in bark of mature loblolly pine (Pinus taeda).

Base – The portion of a plant structure (such as a leaf, bud, stem, etc.) nearest the point of attachment or lowermost; the bottom. (Compare with apex.)

Bisexual – Having functional reproductive structures of both sexes (i.e. male and female) in the same flower or cone. (Compare with unisexual.) [modified from K&P, p. 21]

Blade – The flat, expanded portion of a leaf, petal, sepal, etc. [modified from RDMB, p. 93]

Bract – A modified, usually reduced leaf, often occurring at the base of a flower or cone; in some conifers, such as firs (Abies), bracts are interspersed between the cone scales. [modified from H&H, p. 18]

Branchlet – An ultimate branch, i.e. one located at the end of a system of branches; a small branch. (Compare with twig.) [modified from K&P, p. 22]

Broad-leaved – With leaves that are not needle-like or scale-like, but having relatively broad, flat surfaces, as in most deciduous trees such as maples (Acer) and hickories (Carya). (Compare with needle-like and scale-like.)

Bud – An immature shoot, either vegetative, floral (or cone producing), or both, and often covered by protective scales. [modified from RDMB, p. 88]

Bush – A short shrub that branches from ground level. (Compare with shrub.) [modified from K&P, p. 23]


Calyx – The collective term for all of the sepals of a flower; the outer perianth whorl. (Compare with corolla.) [modified from H&H, p. 20]

Clustered – Leaves grouped closely together at the point of attachment and tending to diverge from one another, as the leaves on short shoots in gingko (Gingko biloba) or the needles on short shoots in larches (Larix). (Compare with fascicled and solitary.) [modified from K&P, p. 29]

Compound – Divided into two or more equivalent parts, as a leaf that consists of multiple, distinct leaflets; not simple. (Compare with simple.) [modified from K&P, p. 31]

Cone – The reproductive structure in conifers comprised of scales and/or other types of modified leaves densely arranged on a central stalk; female, or seed cones, bear ovules on the surface of their scales; male cones produce pollen. (Compare with flower.)

Cone scale – The structure in seed cones, derived from a modified leaf, that bears an ovule on its surface. Cone scales are typically flattened, dry and woody, as the scales of pine (Pinus) cones. However, they may be soft and fleshy, as in junipers (Juniperus), or leathery as in eastern arborvitae (Thuja occidentalis).

Conifer – Cone-bearing plants, such as pines (Pinus).

Corolla – The collective term for all of the petals of a flower; the inner perianth whorl. (Compare with calyx.) [modified from H&H, p. 31]

Crown – The uppermost portion of a tree.


Deciduous – Falling at the end of one growing season, as the leaves of non-evergreen trees; not evergreen. (Compare with evergreen.) [modified from L, p. 748]

Decurrent – With the leaf base extending downward along the stem. [modified from RDMB, p. 134]

Dentate – Toothed along the margin, with pointed teeth that are directed outward rather than forward. (Compare with entire and serrate.) [modified from H&H, p. 157]

Dioecious – Having functionally unisexual (i.e. separate male and female) flowers or cones, which are borne on different plants within the species; thus some plants are male and others are female. (Compare with monoecious and synoecious.) [modified from K&P p. 39]


Entire – With relatively smooth margins that lack teeth, spines or other projections (the margins may be lobed); with a continuous margin. [modified from H&H, p. 157]

Evergreen – Bearing green leaves through the winter and into the next growing season; persisting two or more growing seasons; not deciduous. (Compare with deciduous.) [modified from RDMB, pp. 146 & 154]


Fan-shaped – Shaped like a fan, as a gingko (Gingko biloba) leaf.

Fascicled – In a tight bundle, several leaves appearing to arise from a common point and diverging little if at all, as the needles of many pines (Pinus). (Compare with clustered and solitary). [modified from RDMB, p. 119]

Filament – The stalk of a stamen, which supports an anther at its tip. [modified from K&P, p. 46]

Fleshy – Fairly firm and dense, juicy or at least moist, and easily cut. (Compare with leathery and woody.) [modified from K&P, p. 47]

Floral – upon, within, or associated with the flowers. [K&P, p. 48]

Flower – The reproductive structure in flowering plants (angiosperms), consisting of stamens and/or pistils, and usually including a perianth of sepals and/or petals. (Compare with cone.) [modified from H&H, p. 48]

Four-sided – More or less diamond-shaped in cross section.


Glabrous – Lacking plant hairs (trichomes). (Compare with pubescent.) [modified from W&K, p. 39]

Gland – A distinct structure that produces and secretes a substance such as oil or nectar, or resembles those that do. [modified from K&P, p. 52]

Glaucous – Covered with a whitish or bluish waxy coating (bloom) that can sometimes be rubbed off. [modified from W&K, p. 594]

Globose – Circular in cross section and in outline when viewed from any angle; like a globe or sphere. [modified from K&P, p. 52]

Gymnosperm – A seed plant that produces seeds which are not enclosed inside an ovary, as the conifers. (Compare with angiosperm.) [modified from REE, p. 898]


Internode – The portion of a stem between two nodes, i.e. the part where leaves and/or branches do not arise. (Compare with node.) [H&H, p. 60]

Involute – With margins rolled inward, toward the upper side. (Compare with plane and revolute.) [modified from H&H, p. 157]


Keel – A longitudinal ridge, more or less triangular in cross section, like the keel of a boat. [modified from K&P, p. 61]


Leaf – A lateral outgrowth of a stem, usually green and photosynthetic, and often consisting of a stalk (petiole) and an expanded portion (blade); leaves may also be needle-like or scale-like in form. (Compare with leaflet.) [modified from H&K, p. 24]

Leaflet – One of the separate, leaf-like segments of a compound leaf. [modified from K&P, p. 64]

Leathery – Moderately thick, tough and pliable. (Compare with fleshy and woody.) [modified from K&P, p. 64]

Linear – Long and narrow, with the sides more or less straight and parallel. (Compare with awl-shaped.) [modified from K&P, p. 66]

Lobe – A more or less major protrusion or segment of a leaf or leaflet delimited by concavities (sinuses) in the leaf margin. [modified from K&P, p. 66]

Long shoot – A typically formed stem or branch, without compressed internodes. (Compare with short shoot.)


Margin – The edge, as in the edge of a leaf blade. [H&H, p. 67]

Midrib – A main or primary vein running lengthwise down the center of a leaf or leaf-like structure; a continuation of the leaf stalk (petiole); the midvein. [modified from W&K, p. 598, & K&P, p. 70]

Monoecious – Having functionally unisexual (i.e. separate male and female) flowers or cones, which are borne on the same plant; each plant thus possessing both male and female reproductive structures. (Compare with dioecious and synoecious.) [modified from K&P, p. 70]


Nearly sessile – With a very short, somewhat indistinct stalk. (Compare with sessile and stalked.) [modified from K&P, p. 106]

Nearly symmetric – Not fully symmetric, but divisible into nearly equal halves along one or more planes. (Compare with asymmetric and symmetric.)

Needle – A leaf that is long and thin (more or less needle-shaped) and usually evergreen; it may be flattened as in hemlocks (Tsuga) or more rounded as in pines (Pinus).

Needle-like – With leaves that are more or less needle-shaped, and usually evergreen; they may be flattened as in hemlocks (Tsuga) or more rounded as in pines (Pinus). (Compare with broad-leaved and scale-like.)

Node – The portion of a stem where leaves and/or branches arise; often recognizable by the presence of one or more buds. (Compare with internode.) [modified from H&H, p. 73]


Obtuse – More or less blunt at the apex, with the sides coming together at an angle of greater than 90º. (Compare with acute.) [modified from H&H, p. 153]

Opposite – Positioned in pairs along the stem, the members of each pair at the same level across from one another; two leaves occurring at each node. (Compare with alternate and whorled.) [modified from K&P, p. 75]

Oval – Elliptic in cross section.

Ovary – The lower portion of a pistil where ovules are borne; often distinguishable from the rest of the pistil by its larger circumference. [modified from K&P, p. 75]

Ovoid – Rounded in cross section, broadest near a bluntly rounded base and convexly tapering to a narrower rounded tip; egg-shaped. [modified from K&P, p. 75]

Ovule – The structure in flowering plants and gymnosperms which when fertilized develops into a seed. [modified from H&K, p. 29]


Palmate – With three or more leaflets, lobes or other structures arising from a common point and diverging from one another; arranged or structured in a hand-like pattern. (Compare with pinnate.) [modified from K&P, p. 76 & RDMB, p. 139]

Perennial – Normally living more than two years, with no definite limit to its life span. [K&P, p. 79]

Perianth – The collective term for the outer sterile parts of a flower, comprising the calyx (sepals) and the corolla (petals) when both whorls are present. [modified from W&K, p. 600]

Petal – A unit or segment of the inner floral envelope or corolla of a flower; often colored and more or less showy. (Compare with sepal.) [modified from L, p. 764]

Petiole – The stalk of a leaf. [modified from W&K, p. 600]

Pinnate – With several leaflets, lobes or other structures positioned along and on either side of a central axis; arranged or structured in a feather-like pattern. (Compare with palmate.) [modified from K&P, p. 81]

Pistil – The female or ovule-bearing organ of a flower, typically composed of an ovary, style and stigma. [modified from Z, p. 379]

Plane – With midrib and margin all in one plane, or nearly so; flat. (Compare with involute and revolute.) [modified from W&K, p. 39]

Plated – Bark with relatively large, more or less flat plates, as in mature loblolly pine (Pinus taeda) or mature white oak (Quercus alba).

Pollen – The small, often powdery, grains which contain the male reproductive cells of flowering plants and gymnosperms. [modified from H&K, p. 33]

Pollen cone – A male or pollen-producing cone; typically smaller and of shorter duration than seed cones.

Prickle – A small, sharp structure developed from outgrowth of the surface of bark or epidermis. (Compare with spine and thorn.) [modified from W&K, p. 39]

Pubescent – Bearing plant hairs (trichomes). (Compare with glabrous.) [modified from W&K, p. 39]


Reflexed – Bent backward or downward. (Compare with appressed, ascending and spreading.) [modified from H&H, p. 98]

Resin pocket – A small indentation in the surface of the bark of some conifer species where resin or pitch accumulates; a pitch pocket.

Resinous – Bearing resin and often, therefore, sticky. [H&H, p. 98]

Revolute – With margins rolled backward, toward the underside. (Compare with involute and plane.) [modified from H&H, p. 158]

Root – The portions of a plant that are anatomically distinct from the shoot and that lack nodes and internodes; roots serve for anchorage, absorption and/or storage, and usually grow below ground. (Compare with shoot.) [modified from K&P, pp. 87-88 (see radix)]


Scale (1) – Small, flattened structures that are usually thin, dry and membranous in texture.

Scale (2) – Small, often triangular shaped, leaves that are appressed to the branchlets as in juniper (Juniperus).

Scale-like – With small, typically triangular-shaped leaves that are often appressed to the branchlets, as in juniper (Juniperus). (Compare with broad-leaved and needle-like.) [modified from W&K, p. 603]

Seed – A mature or ripened ovule. [modified from K&P, p. 95]

Seed cone – A female or ovule-producing cone; typically larger and persisting longer than pollen cones.

Sepal – A unit or segment of the outermost floral envelope or calyx of a flower; usually green and leaf-like. (Compare with petal.) [modified from L, p. 769]

Serotinous – Having cones that remain closed long after the seeds are ripe. [modified from D, p. 1143]

Serrate – Toothed along the margin, the sharp teeth pointing forward; sawtoothed. (Compare with dentate and entire.) [modified from H&H, p. 158 & K&P, p. 97]

Sessile – Without a stalk, positioned directly against the bearing structure. (Compare with nearly sessile and stalked.) [modified from W&K, p. 604]

Shoot (1) – The portions of a plant that are anatomically distinct from the root and differentiated into nodes, where leaves and branches originate, and the spaces in between (internodes); shoots consist of stems, leaves and any other structures borne from the stem. (Compare with root.) [modified from K&P, p. 98]

Shoot (2) – A young stem or branch. [H&H, p. 107]

Short shoot – A stumpy, slow growing, lateral branch with very short internodes, often bearing flowers; a dwarf shoot. (Compare with long shoot.) [modified from W&K, p. 604]

Shrub – A relatively short, woody, perennial plant, usually without a single stem or trunk, and often with many crowded branches. (Compare with bush and tree.) [modified from RDMB, p. 88]

Simple – Undivided, as a leaf blade that is not separated into distinct leaflets; not compound. (Compare with compound.) [modified from H&H, p. 156]

Sinus – The space or recess between two divisions or lobes of an organ such as a leaf or petal. [modified from L, p. 770]

Smooth – Bark having a more or less continuous, even surface, with relatively few fissures or protrusions, as in American beech (Fagus grandifolia). [modified from H, p. xx]

Solitary – Occurring singly and not borne in a cluster or group. (Compare with clustered and fascicled.) [modified from H&H, p. 175]

Spine – A woody, sharp-pointed, modified leaf or leaf part. (Compare with prickle and thorn.) [modified from W&K, p. 39]

Spiral – Arranged along the stem in such a way that a line connecting the points of attachment would form a spiral; a form of alternate arrangement. [modified from H&K, p. 39]

Spreading – Extending outward horizontally, or upward at an angle between 90º to 45º relative to the bearing structure. (Compare with appressed, ascending and reflexed.) [modified from K&P, p. 102]

Stalk – A supporting axis or column that bears a structure at its apex and is usually narrower than the structure being borne, as the stalk of a flower or leaf. [modified from K&P, p. 102]

Stalked – With a stalk. (Compare with nearly sessile and sessile.)

Stamen – The male reproductive organ in a flower that produces and releases pollen, composed of an anther usually borne on a stalk (filament). [modified from Z, pp. 384-85]

Stem – The axis of a shoot, bearing leaves, bracts and/or flowers, and usually growing above ground, but sometimes specialized and growing underground or on the surface of the ground; stems are differentiated into regions called nodes, where leaves and branches originate, and internodes. [modified from K&P, p. 103]

Sterigma – A persistent leaf base that remains on the twig after the leaf falls, appearing as peg-like projection.

Stigma – The pollen-receptive region at the tip of a pistil. [modified from Z, p. 385]

Stomate – A microscopic pore on the surface of a leaf, stem or other surface, that controls moisture loss and exchange of gases.

Stout – With armature that is relatively thick and sturdy; not breaking easily. (Compare with weak.)

Style – The more or less elongated portion of a pistil between the ovary and the stigma. [modified from L, p. 772]

Symmetric – Divisible into essentially equal halves along one or more planes. (Compare with asymmetric and nearly symmetric.) [modified from K&P, p. 108]

Synoecious – With all flowers or cones bisexual, i.e. bearing functional reproductive structures of both sexes. (Compare with dioecious and monoecious.) [modified from K&P, p. 109]


Thorn – A woody, sharp-pointed, modified stem. (Compare with prickle and spine.) [modified from W&K, p. 39]

Three-sided – More or less triangular-shaped in cross section.

Tree – A relatively tall, woody, perennial plant usually with a single stem (trunk) that bears branches. (Compare with shrub.) [modified from RDMB, p. 88]

Trichome – Any type of plant hair (except for root hairs). [W&K, p. 607]

Trunk – The aboveground, relatively stout, main stem of a tree; the bole. [modified from K&P, p. 133]

Twig – The relatively small end portion of a woody branchlet; a small branchlet. (Compare with branchlet.) [modified from K&P, p. 114]

Two-sided – More or less flat in cross section, with an upper and lower surface.

Two-ranked – Arising from the bearing axis in two rows, usually on opposite sides. [modified from H&H, p. 128]


Unarmed – Without a hook, prickle or other sharply pointed structure on the end of the cone scale. (Compare with armed.)

Unisexual – Having functional reproductive structures of only one sex in the flower or cone. (Compare with bisexual.) [modified from K&P, p. 115]


Vegetative – Of, or relating to, the non-reproductive parts of a plant.


Weak – With armature that is slender and tends to break easily. (Compare with stout.)

Whorled – With three or more leaves positioned on the stem at the same level; three or more leaves occurring at each node. (Compare with alternate and opposite.) [modified from K&P, p. 119]

Woody (1) – With an aboveground shoot composed of relatively hard tissue that persists from one growing season to the next.

Woody (2) – Of or resembling wood, and thus relatively hard and dry. (Compare with fleshy and leathery.) [modified from K&P, p. 119]



D           Dirr, Michael A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses, 5th ed. Stipes Publishing: Champaign, Illinois.

H&H      Harris, James G. and Melinda Woolf Harris. 2001. Plant Identification Terminology: An Illustrated Glossary, 2nd ed. Spring Lake Publishing: Spring Lake, Utah.

H&K      Hickey, Michael and Clive King. 2000. The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press: Cambridge.

H           Hightshoe, Gary L. 1978. Native Trees for Urban and Rural America: A Planting Design Manual for Environmental Designers. Iowa State University Research Foundation: Ames, Iowa.

K&P       Kiger, Robert W. and Duncan M. Porter. 2001. Categorical Glossary for the Flora of North America Project. Hunt Institute for Botanical Documentation, Carnegie Mellon University: Pittsburgh, Pennsylvania.

L            Lawrence, George H. M. 1951. Taxonomy of Vascular Plants. The MacMillan Company: New York.

RDMB    Radford, Albert E., William C. Dickison, Jimmy R. Massey, and C. Ritchie Bell. 1974. Vascular Plant Systematics. Harper & Row Publishers: New York, Evanston, San Francisco, London.

REE       Raven, Peter H., Ray F. Evert, and Susan E. Eichhorn. 1999. Biology of Plants, 6th ed. Worth Publishers: New York.

W&K      Walters, Dirk R. and David J. Keil. 1996. Vascular Plant Taxonomy, 4th ed. Kendall/Hunt Publishing: Dubuque, Iowa.

Z            Zomlefer, Wendy B. 1994. Guide to Flowering Plant Families. University of North Carolina Press: Chapel Hill, NC & London.