United Kingdom

Armenian crane's-bill

Geranium psilostemon

Arrow bamboo

Pseudosasa japonica

arrow-head scale

Unaspis yanonensis

Arrowleaf clover

Trifolium vesiculosum

Arsenic bush

Senna septemtrionalis

Atlantic Giant Pumpkin

Cucurbita maxima

Atlantic Ninebark

Physocarpus opulifolius

Atlantic rangia

Rangia cuneata

Atlantic Stream Crayfish

Austropotamobius pallipes

Atlantic Surf Clam

Spisula solidissima

Atlas Poppy

Papaver atlanticum

Aubretia

Aubrieta deltoidea

Auricula

Primula auricula

Ascochyta syringae

Ashy Cinquefoil

Potentilla inclinata

Asian Ambrosia Beetle

Xyleborinus attenuatus

Asian Bittersweet

Celastrus orbiculatus

Asian China-mark

Elophila difflualis

Asian Hornet

Vespa velutina

Asian Longhorned Beetle

Anoplophora glabripennis

Asian Skunk-cabbage

Lysichiton camtschatcensis

Asiatic Dayflower

Commelina communis

Astrantia

Astrantia major

Asian brush crab

Hemigrapsus takanoi

Asian Bush Mosquito

Aedes japonicus

Asian chestnut gall wasp

Dryocosmus kuriphilus

Asian Clam

Corbicula fluminalis

Asian date mussel

Arcuatula senhousia

Asian drill snail

Ocinebrellus inornatus

Asian kelp

Undaria pinnatifida

Asian Lady Beetle

Harmonia axyridis

Asian netvein hollyfern

Cyrtomium fortunei

Asian Shore Crab

Hemigrapsus sanguineus

Asian Tiger Mosquito

Aedes albopictus

Asparagus Beetle

Crioceris asparagi

aspen daisy

Erigeron speciosus

Aster-Like Boltonia

Boltonia asteroides

Bethlehem Lungwort

Pulmonaria saccharata

bigpod sesbania

Sesbania herbacea

Billard's Bridewort

Spiraea billardii

Billion-Dollar Grass

Echinochloa frumentacea

Bird-In-A-Bush

Corydalis solida

Bird'S-Eye Gilia

Gilia tricolor

birthwort

Aristolochia clematitis

Bicolored trailing ant

Monomorium floricola

Bieberstein's Crocus

Crocus speciosus

Bieberstein's freshwater crab

Potamon ibericum

Big-Bract Vervain

Verbena bracteata

Bigcone Pine

Pinus coulteri

Bighead knapweed

Centaurea macrocephala

black rat

Rattus rattus

black Sea jellyfish

Blackfordia virginica

black slug

Milax nigricans

Black soldier fly

Hermetia illucens

Blackspot hornpoppy

Glaucium corniculatum

Black Spruce

Picea mariana

Bithynian vetch

Vicia bithynica

Bitternut

Carya cordiformis

Bladder Campion

Silene latifolia

Bladder Ketmia

Hibiscus trionum