Plants

Annual Tree Mallow

Annual Tree Mallow (Lavatera) — overview, identification, and garden uses

Anthurium

Aphid

Aphid: biology, impact on plants, control, and notable facts

Apiaceae

Apiales

Apiales: the order of umbels and related flowering plants

Apocynaceae

Apocynaceae — the dogbane and oleander family

Apocynum cannabinum

Apocynum cannabinum (Indian hemp)

Apple

Apple (Malus): fruit, tree, cultivation, uses, and global importance

Apricot

Aquatic plant

Aquatic plant: types, adaptations, roles and uses

Aquilegia

Aquilegia (columbine): spurred perennial flowers of the Northern Hemisphere

Arabidopsis thaliana

Araceae

Araceae (Arum family): characteristics, ecology, uses, and notable genera

Araliaceae

Araliaceae: the ivy family — diversity, features, and uses

Araucaria

Araucaria: ancient conifer genus and its natural history

Araucaria heterophylla

Araucaria heterophylla (Norfolk Island Pine)

Arboriculture

Archaefructus

Archaefructus: an early aquatic flowering-plant genus

Arctic willow

Arctic willow (Salix arctica)

Argemone

Argemone (prickly poppy): description, distribution, uses and risks

Aristolochia

Aristolochiaceae

Aristolochiaceae (Birthwort or Pipevine Family)

Artemisia (genus)

Artemisia (genus of flowering plants)

Artemisia absinthium

Artemisia annua

Artichoke

Asclepiadoideae

Asclepiadoideae — the milkweed subfamily

Asclepias amplexicaulis

Asclepias asperula

Asclepias asperula (antelope horns)

Asclepias californica

Asclepias curassavica

Asclepias curassavica — scarlet milkweed (Mexican butterfly weed)

Asclepias curtissii

Curtiss's milkweed (Asclepias curtissii)

Asclepias eriocarpa

Asclepias eriocarpa — woollypod (Indian) milkweed

Asclepias erosa

Asclepias erosa — desert milkweed

Asclepias fascicularis

Asclepias fascicularis — Narrowleaf (Mexican) Milkweed

Asclepias humistrata

Asclepias humistrata — sandhill (pinewoods) milkweed

Asclepias nivea

Asclepias nivea — Caribbean milkweed

Asclepias physocarpa

Asclepias physocarpa — swan plant (balloon milkweed)

Asclepias purpurascens

Asclepias purpurascens (Purple Milkweed)

Asclepias syriaca

Asclepias syriaca — common milkweed

Asclepias tuberosa

Asclepias tuberosa (butterfly weed)

Ash tree

Ash tree (Fraxinus): description, uses, distribution and threats

Asparagaceae

Asparagaceae: the asparagus family of flowering plants

Asparagales

Asparagales — order of monocot flowering plants

Asparagus

Asparagus: botany, cultivation, uses, and notable facts

Asparagus officinalis

Asparagus officinalis (garden asparagus)

Aspen

Aspen (Populus): description, biology, uses and notable facts

Aster (genus)

Aster (genus) — Old World asters and their taxonomy