Abaxial.   Away from the axis; the lower surface of the leaf; dorsal
Abcissent.   Falling off or separating at a specific separation (abcission) layer, as in most deciduous plants


Acarpous.   No carpels or carpellate whorl; no pistil


Bud.   Accessory Bud - Buds lateral to or above axillary buds; Accessory Organs - The calyx and corolla


Accrescent.   Growing after flowering or bud development has occurred, as the sepals in Hypericum and bud scales in Carya


Accumbent or Pleurorhizal.   Reclinate with cotyledon edges against hypocotyl


Acerose.   Needle-shaped; sharp


Achene.   A one-seeded, dry, indehiscent fruit with seed attached to fruit wall at one point only, derived from a one-loculed superior ovary


Achenecetum.   An aggregation of achenes, as in Ranunculus


Achlamydeous.   Without perianth


Acicular.   Needlelike, round or grooved in cross section


Aciculate.   Finely marked as with pin pricks, fine lines usually randomly arranged


Acrocaulous.   With terminal branches


Acrocidal Capsule.   One that dehisces through terminal slits, or fissures, as in Staphylea


Acrodromous.   With two or more primary or strongly developed secondary veins diverging at or above the base of the blade and running in convergent arches toward the apex over some or all of the blade length, the arches not basally curved


Acropetal.   Developing upward, toward apex


Acroramous.   Leaves terminal, near apex of branch


Acroscopic.   Facing apically


Actinodromous.   With three or more primary veins diverging radially from a single point at or above the base of the blade and running toward the margin, reaching it or not


Actinomorphic or Radial.   With floral parts radiate from center like spokes on wheel


Actinostele.   A protostele having a xylem core in the form of radiating ribs, as viewed in transverse section


Aculeate.   Prickly


Acuminate (Base narrowly cuneate).   Margins straight to convex forming a terminal angle of less than 45


Acute (Base cuneate).   Margins straight to convex forming a terminal angle 45-90


Adaxial.   Next to the axis; facing the stem; ventral


Adherent.  With unlike parts of organs joined, but only superficially and without actual histological continuity


Adnate.   With unlike parts or organs integrally fused to one another with histological continuity


Adventitious.   Arising from organ other than root; usually lateral


Aerating or Knee.   Vertical or horizontal aboveground roots


Aerial or Epigeous.   Above the ground or water, in the air; aerial stem - an erect stem arising from a horizontal rhizome


Aerocaulous.   With aerial stems


Aerophyllous.   With aerial leaves


Aestival.   Appearing in summer


Agamandrous.   Inflorescence with neuter flowers inside or above and staminate outside or below (agamandrocephalous)


Agamogynous.   Inflorescence with neuter flowers inside or above and pistillate outside or below (agamogynecephalous)


Agamohermaphroditic.   Inflorescence with neuter flowers inside or above and hermaphroditic outside or below (agamohermaphrodicephalous)


Agamous or Neuter.   Without sex; sexual organs abortive


Agglomerate, Conglomerate, Crowded, or Aggregate.   Dense structures with varied angles of divergence


Aianthous or Semperflorous.   With flowers appearing throughout the year


Alate.   Winged


Allagostemonous.   Having stamens attached to petal and torus alternately


Allautogamy.   Cross- and self-fertilization in same plant, as in Viola


Allogamy or Xenogamy.   Cross-fertilization in plants


Allopatric.   Isolated, separated


Alternate.   One leaf or other structure per node


Alveolate.   Honey-combed


Ament or Catkin.   A unisexual spike or elongate axis with simple dichasia that falls as a unit after flowering or fruiting


Amorphic or Paleomorphic.   Flowers without symmetry; usually with an indefinite number of stamens and carpels, and usually subtended by bracts or discolored upper leaves; e.g., Salix discolor, Echinops ritro (mostly fossil forms)


Amphicarpous.   With fruits in two environments; e.g., aerial and subterranean


Amphiflorous.   Flowers above and below ground, as in Amphicarpum


Amphisarca.   A berry-like succulent fruit with a crustaceous or woody rind, as in Lagenaria


Amphitropous.   With body bent or curved on both sides so that the micropyle is near the medially attached funiculus


Amplexicaul.   Completely clasping the stem


Ampliate.   Enlarged; dilated


Anadromous.   Having the first lobe or segment of a pinna arising basiscopically in compound leaves


Anatropous.   With body completely inverted so that funiculus is attached basally near adjoining micropyle area


Ancipital.   Two-edged


Andragamous.   Inflorescence with staminate flowers inside or above and neuter flowers outside or below (andragamocephalous)


Androdioecious.   Some plants with staminate flowers and some with perfect flowers


Androecium.   One or more whorls or groups of stamens; all stamens in flower


Androgynecandrous.   Inflorescence with staminate flowers above and below pistillate, as in the spikes of some species of Carex


Androgynophore.   The stipe or column on which stamens and carpels are borne


Androgynous.   Inflorescence with staminate flowers inside or above and pistillate outside or below (androgynecephalous)


Androhermaphroditic.   Inflorescence with staminate flowers inside or above and hermaphroditic outside or below (androhermaphrodicephalous)


Andromonoecious.   Plant with staminate and perfect flowers


Anemophily.   Pollinated by wind


Angustate.   Narrow


Anisocarpous.   With unequal carpels


Anisocotylous.   With unequal cotyledons


Anisolateral.   With unequal sides


Anisopetalous.   With unequal petals


Anisophyllous.   With unequal leaves


Anisostylous.   With unequal styles


Annotinal or Yearly.   Appearing yearly


Annual.   Living one year or less. Winter Annual - Living less than one year but through the winter; germination usually in late fall, and usually flowering and fruiting in early spring


Annular.   Ring-like


Annulus.   Thick-walled ring of cells on the sporangium


Anomalicidal or Rupturing Capsule.   One that dehisces irregularly, as in Ammannia


Anterior.   Anterior Lobes - The lobes away from axis, toward the subtending bract, abaxial lobes; Anterior Ridges, Lines, Grooves - The lines, grooves, ridges in or on the dorsal side, abaxial, within the perianth


Anther.   Pollen-bearing portion of stamen


Antheridium.   The male sex organ producing the sperm


Anthesis.   Time of flowering; opening of flower with parts available for pollination


Anthocarpous.   Having a body of combined floral and fruit parts, as in multiple fruits


Anthotaxis.   Arrangement of sporophylls, primarily reproductive in function


Anthropophily.   Pollinated by man


Antipetalous.   Opposite the petals


Antisepalous.   Opposite the sepals


Antitropous.   With radicle pointing away from hilum


Antrorse.   Bent or directed upward


Apetalous.   No petals or corolla


Aphyllopodic.   Without blade-bearing leaves at base of plant


Aphyllous.   Without leaves, no whorls of leaves


Apical or Terminal.   At the top, tip, or end of a structure


Apiculate.   More than 3:1 l/w, usually slightly curled and flexuous


Apocarpous.   With carpels separate


Apogamy.   Producing sporophytes from a gametophyte without fertilization


Apopetalous or Choripetalous.   With separate petals


Apophysis.   Exposed outer surface of either an ovuliferous scale or megasporophyll as seen when the cone is closed


Aposepalous or Chorisepalous.   With separate sepals


Apospory.   Producing gametophytes directly from a sporophyte without producing spores


Apostemonous.   With separate stamens


Appendicular.   Typical stamen with a variously-shaped or modified, protruding connective, as in Viola


Applanate or Plane.   Flat, without vertical curves or bends


Appressed or Adpressed.   Pressed closely to axis upward with angle of divergence 15 or less


Arachnoid.   Cobwebby


Arborescent.   Tree-like in appearance and size


Archegonium.   The female sex organ producing the egg


Arcuate.   Curved like a crescent, can be downward or upward


Areolate.   Divided into many angular or squarish spaces


Areoles.   The spaces formed by a vein network


Arhizous.   Without roots, no whorls of roots


Aril.   Outgrowth of funiculus, raphe, or integuments; or fleshy integuments or seed coat, a sarcotesta at base of the fleshy seed; e.g., Cepalotaxus


Arillate.   General term for an outgrowth from the funiculus, seed coat or chalaza; or a fleshy seed coat


Aristate.   More than 3:1 l/w, usually prolonged, straight and stiff


Articulate.   Generally meaning having a joint as in leaves, leaflets or stems, as in heterophyllous species of Selaginella; or having a swollen area, often discolored, at the point of branching of the stem


Ascending.   Directed upward with an angle of divergence of 16-45


Asepalous.   No sepals or calyx


Asperous.   Having a rough surface


Assurgent.   Directed upward or forward


Astemonous or Anandrous.   No stamens or androecium


Astylocarpellous.   Without a style and a stipe


Astylocarpepodic.   Without a style, with a stipe


Astylous.   Style absent


Asymmetric.   Without regularity in any dimension


Attenuate.   Elongate, tapering, usually applied to base


Auriculate.   Lobe rounded; sinus depth variable; outer margin concave, inner convex or straight


Auriculiform.   Usually obovate with two small rounded, basal lobes


Autogamy.   Self-fertilization in a single flower


Autumnal.   Appearing in autumn


Awl-shaped Leaf.   Subulate; narrow, flat, stiff, sharp-pointed, usually less than 1/2 in. long; e.g., Juniperus


Axial.   With branches arising from buds in leaf axil


Axile.   With the placentae along the central axis in a compound ovary with septa


Axillary or Lateral.   In axils of leaves or leaf scars; axillary leaves - leaves borne in the axils of branches, as in heterosporous species of Selaginella