Glossary: A

abaxial abaxial
On the side away from the axis, usually refers to the underside of a leaf relative to the stem.
abscission abscission
Shedding branches, leaves, or flowers at a seam; usually seasonally (i.e., leaves abscise in the Fall in New England).
acaulescent acaulescent
With lower leaves reduced to sheaths or scales so that leaves/flowers appear to arise directly from rootstock.
acaulous
Without a stem.
achene achene
A dry, usually 1-seeded fruit that does not separate or split open at maturity.
achlorophyllous
Lacking chlorophyll and therefore incapable of photosynthesis.
acropetal acropetal
In the direction of the tip or apex.
acroscopic acroscopic
In the direction of the tip or apex.
actinomorphic actinomorphic
Radially symmetrical; a shape that can be divided by 2 or more planes into roughly equal halves, usually refers to the perianth of a flower.
acuminate acuminate
Tapering to a narrow point, more tapering than acute, less than attenuate.
acute acute
Condition of an apex with more or less straight sides that meet to form an angle of less than 90°, more pointed than obtuse, but less pointed than acuminate.
adaxial adaxial
On the side toward the axis, usually refers to the top side of a leaf relative to the stem.
adnate adnate
An organ that is fused with a structure different from itself, as when stamens are attached to petals.
adpressed adpressed
Lying close and flat, usually referring to leaves growing up against the stem.
adventitious adventitious
A structure such as a bud or root that is produced on an unusual part of the plant (i.e., roots that come from stems).
adventive
A species not intentionally introduced; growing here and there.
aerenchyma aerenchyma
Plant tissue that is filled with large air spaces, usually in the stem or rhizome/root.
aerial
Above-ground.
aerial leaves aerial leaves
On aquatic plants, the leaves that are produced above the water's surface.
aggregate fruit aggregate fruit
A fruit such as a raspberry that is actually composed of multiple, fused fruits (small drupes).
Agrotis ipsilon Agrotis ipsilon
Black Cutworm, photo ©Adam Sisson, Iowa State University, Bugwood.org.
Allagrapha aerea Allagrapha aerea
Unspotted Looper Moth, photo ©Carol Wolf, North American Moth Photographers Group.
allopatric
Species that do not occur in the same geographic ranges.
alternate alternate
A node bears only 1 similar organ, such as a leaf or flower (compare with opposite, whorled).
alveolate alveolate
With many angular cavities, like a honeycomb.
ament ament
Catkin: a slender, usually pendulous inflorescence, with crowded male or female flowers.
amphibious
Plants adapted to living in water or on land.
amphistomic amphistomic
With stomata on both leaf surfaces.
ampliate
Epanding or enlarged.
Anageshna primordialis Anageshna primordialis
Yellow-spotted Webworm Moth, photo ©Carol Wolf, North American Moth Photographers Group.
Anagrapha falcifera Anagrapha falcifera
Celery Looper, photo ©Robert J. Bauernfeind, Kansas State University, Bugwood.org.
Andrena barbilabris Andrena barbilabris
Long-lipped Mining Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Andrena ceanothi Andrena ceanothi
Mining Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Andrena miranda Andrena miranda
Mining Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Andrena nasonii Andrena nasonii
Nason's Mining Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Andrena ziziae Andrena ziziae
Golden-Alexanders Andrena, photo ©Brooke Alexander, USGS Native Bee Inventory and Monitoring Laboratory.
androecium androecium
The collective term for the male organs (stamens) of the flower.
androgynous androgynous
With both male and female flowers in the same inflorescence.
anemophilous
Wind-pollinated.
angiosperm
Flowering plants that bear seeds that are enclosed in an ovary.
angular angular
With edges where two planes meet (come together at an angle). Opposite: "rounded.".
anisophyllous anisophyllous
With two opposite leaves of very different sizes at the same node.
annual
A plant that lives for only one year.
annual growth constrictions annual growth constrictions
In Lycophytes, areas of the stem with smaller leaves that are produced at the colder beginning and end of the growing season.
annular annular
Like a ring, or with organs arranged in a ring.
annulus
Ring of specialized cells encircling a fern sporangium.
antepetalous antepetalous
When the stamens are positioned opposite the petals in a flower.
anterior anterior
Positioned in front of.
antesepalous antesepalous
When the stamens are positioned opposite the sepals in a flower.
anther anther
The pollen-bearing structure in a flower, usually borne at the end of a stalk called a filament.
antherode antherode
A sterile, modified anther.
Anthidiellum notatum Anthidiellum notatum
Leaf-cutting Bee, photo ©Joyce Amihere, USGS Native Bee Inventory and Monitoring Laboratory.
anthocyanic anthocyanic
Tinged or colored with a pink, red, or purple pigment.
anthocyanin
A purplish-red, usually protective pigment.
Anthophora abrupta Anthophora abrupta
Chimney Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Anthophora terminalis Anthophora terminalis
Orange-tail Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
anthropogenic
Caused, introduced by, or resulting from human activity; a disturbed or man-made habitat.
Anticarsia gemmatalis Anticarsia gemmatalis
Velvetbean Caterpillar Moth, photo ©Jim Vargo, North American Moth Photographers Group.
antrorse antrorse
Pointing upward or forward toward the distal end.
apetalous apetalous
With no petals.
apex (plural: apices) apex (plural: apices)
Tip or top.
aphyllopodic
With basal leaves much reduced or absent.
apiculate apiculate
With an abrupt, short, projected tip.
apiculus apiculus
A short projected tip.
Apis mellifera Apis mellifera
European Honey Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
aplexicaulous aplexicaulous
Clasping, as with a leaf with two bases that wrap around the stem.
apomictic
The production of seeds without fertilization.
apomixis
The production of seeds without fertilization.
apophysis apophysis
The outer part of a cone scale that is exposed even when the cone is closed.
apparently secure
Uncommon but not rare; some cause for concern due to declines or other factors.
appendage appendage
A secondary projection, ear, or other piece of tissue attached to a main structure.
appressed appressed
Lying close and flat, usually referring to leaves growing up against the stem.
aquatic
Living in water.
arcuate arcuate
Arching, as in curving veins in a leaf blade.
areole areole
A bounded space, as with leaves with net-like venation.
aril aril
An appendage of a seed, usually brightly colored, fleshy, and/or sweet, that attracts animals to eat it and coincidentally disperse the seed.
aristate aristate
Tipped with a long, slender bristle.
armature armature
Protective sharp projections like bristles, barbs, or thorns.
armed armed
Bearing a sharp projection such as a prickle, spine, or thorn.
articulated articulated
One structure joined to another, usually at a point where the two will separate.
ascending ascending
Diverging from an axis at an angle of 15–45°, less upward than erect, less outward than spreading.
asexual
Without male or female organs; reproducing vegetatively, without fertilization by another plant.
asymmetrical asymmetrical
With unequally sized or shaped parts on either side of a central axis.
attenuate attenuate
Tapering very gradually to a prolonged tip or base.
Augochlora pura Augochlora pura
Golden Green Sweat Bee, photo ©Phillip Moore, USGS Native Bee Inventory and Monitoring Laboratory.
Augochlorella aurata Augochlorella aurata
Blue-green Sweat Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
Augochloropsis sumptuosa Augochloropsis sumptuosa
Blue Sweat Bee, photo USGS Native Bee Inventory and Monitoring Laboratory.
auricle auricle
Ear-like lobe (usually refers to a leaf base).
authority
The botanist who first officially named a taxon.
Autographa ampla Autographa ampla
Large Looper Moth, photo ©Jim Vargo, North American Moth Photographers Group.
Autographa precationis Autographa precationis
Common Looper Moth, photo ©David Cappaert, Bugwood.org.
autotroph
A plant that makes its own food from raw materials obtained from the sun, water, and soil.
avleolus avleolus
Depressions or cavities in a surface.
awn awn
Fine bristle (usually referring to scales of Carex or bracts of grass flowers).
axil axil
The juncture where a lateral organ, such as a leaf, joins a main axis, like a stem.
axillary flower axillary flower
A flower that emerges from an axil (i.e. the juncture between a branch or leaf and the stem).
axis axis
The main stem of a structure, such as a plant or inflorescence.