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