Abscissing:- Natural detachment of parts of a plant, typically dead leaves and ripe fruit.
Increasing in length or thickness with age.
A single-seeded dry fruit, not splitting.
Acicle:- Needle-like prickle.
Acicular:- Needle-shaped very narrow, stiff, and pointed.
Acrodromous:- With two or more main veins starting at the base of the leaf, running parallel to the leaf margin and meeting ( or almost) at the apex.
Actinomorphic:- A regular flower, radially symmetrical and cap­able of being cut into two equal halves in various directions.
Acumen:- A protuberance from a plant body or organ.
Acuminate:- Gradually narrowing to a point.
Aculeolate:- With small prickles or sharp points.
Acute:- Sharp, sharply pointed, the margins near the tip being almost straight.
Adaxial:- Side of an organ towards the axis on which it is inserted, (e.g. the upper surface of a leaf).
Adpressed - Appressed:- Pressed close to another organ - hairs close to the stem for instance.
Appressed - hairy:- With hairs lying close to the stem.
Appressed - tomentose:- Densely covered in short soft, matted hair, lying close to the stem.
Adnate:- Attached to, surface to surface; usually said of different organs or structures (e.g. stamen adnate to a petal)
Aerial:- Growing or borne above the ground or water.
Spot on the surface of cacti where clusters of spines or bristles arise. - as on the sur­face of many cacti.
Aestivation:- The way in which sepals and petals are folded or packed in bud.
Alar:- Flower borne in the fork of two branches of a dichasium.
Amplexicaul:- Clasping the stem, but not completely encircling it.
Anastomosing- Forming a network; vein branches uniting where they come into contact.
Anemophilous:- Wind-pollinated.
Angustiseptate:- Having a silicula (broad, flat capsule) laterally compressed with a narrow septum (dividing wall or enclosure).
Anthophore. plural -s. Stalk-like extension of the receptacle on which the pistil and corolla are borne.
Alternate:- Leaves alternating along the stem, as opposed to op­posite or whorled.
Alveolate:- Pitted like a honeycomb; similar to fove(ol)ate, but with the depressions angled rather than round.
Anatropous:- Of an ovule. reversed; bent parallel to its stalk so the micropyle is close to the point of funiculus attachment.
Anther:- The fertile part of the stamen - the upper part which con­tains the pollen.
Anthesis:- The period during which a flower is fully open and functional.  when the flower is fully open, when in full bloom.
Antrorse:- Pointing forwards or upwards.
Antrorsely - scabridulous:- Slightly roughly bristly, bristles pointing forwards or upwards.
Apex:- Refers to the highest or furthest point of a plant stem, root, leaf, etc.
Apical:- Of the apex; also used in the sense of distal (which is preferred).
Apiculate:- Ending in an abrupt, short point.
Apiculum:- Short, sharp, but not stiff point.
Appendiculate:- With appendage or appendages.
Appressed:- Lying close and flat (e.g. branches or hairs on a stem).
Appressed - setulose:- with close lying minute bristles.
Arachnoid hairs:-
Fine interlaced hairs resembling a spider's web.
Arachnoid - lanate With long dense curly interwoven matted woolly hairs, resembling a spider's web.
Arachnoid - pilose:- With dense curly interwoven matted fine hairs.
Arachnoid - tomentose:- Densely covered in short soft, matted hairs, resembling a spider's web.
Curved like a bow, bow-like.
Aristate:- With a bristle-like pointed axis.
A long, bristle-like pointed axis.
With a short beard or awn.
Ascending:- Curving or pointing upwards.
Attenuate:- Gradually narrowing over a long distance.
Auricle:- Small ear-like projections or appendages, often at the base of leaves.
Auriculate:- Equipped with ear-like structures, usually near the base.
A stiff bristle-like projection, sometimes barbed or feathered. a fine bristle ending an organ.
Axil:- The angle between the leaf and stem.