Amarella/Gentianella/Gentian:  Budd's Flora (BF) places this species in broadly circumscribed genus Gentian.  Flora of Alberta (FOA) has removed a number of species (including this one) from Gentian sensu lato and placed them in a new, smaller genus Gentianella.  The following are answers to key questions leading to genus Gentian in Budd's Flora, leading to genus Gentianella in Flora of Alberta, and leading to species amarella in both floras.

	plants with simple opposite leaves; NOT [plants with trifoliolate leaves]
	flowers short-peduncled, NOT [flowers long-peduncled]
	flowers usually less than 1.5 cm long; NOT [flowers usually more than 2 cm long]
	calyx-lobes with green margins; NOT [calyx-lobes with thin hyaline margins]
	corolla not spurred at base; NOT [corolla, at least in the larger flowers, with 4 hollow spurs at base]
	corolla tubular to funnelform or nearly cup-shaped; NOT [corolla rotate] (FOA)
	corolla campanulate or bell-shaped; NOT [corolla rotate] (BF)
	corolla tube as long as or longer than the lobes; NOT [corolla tube much shorter than the lobes]
	corolla WITHOUT plaits or folds between the lobes; NOT [corolla with plaits or folds between the lobes]
	corolla-lobes entire or sparingly toothed; NOT [corolla-lobes fringed or toothed]
	corolla-lobes acute or obtuse; NOT [corolla-lobes apiculate or setose at tips]
	corolla lobes 5-9 veined; NOT [corolla lobes 3-veined]
	throat of corolla with a fringe of hairs; NOT [throat of corolla hairless]
	stamens on the corolla tube; NOT [stamens inserted at base of corolla]
	nectaries upon the base of the corolla-tube alternate with the stamens; NOT [nectaries at the base of the ovary]

Gentianaceae: Note that the key to the families in Budd's Flora requires flowers in cymose clusters; NOT [flowers scorpioid or solitary in leaf axils] in order to distinguish Gentianaceae from Hydrophyllaceae.  Although many authors define scorpioid as a type of cyme, Budd's Flora defines it as of an inflorescence, uncoiling as the flowers develop.  It defines cyme as a cluster of flowers in which the central flowers open first.  The rest of the answers to key questions in Budd's Flora leading to family Gentianaceae are listed below:

	herbs; NOT [shrubs or trees]
	plants green or with some chlorophyll; NOT [plants parasitic or saprophytic, without chlorophyll]
	plants NOT twining
	plants WITHOUT milky juice
	leaves opposite; NOT [leaves alternate or basal]
	flowers NOT in heads or spikes; NOT [flowers in long or short spikes], NOT [flowers in heads or in form resembling a head]
	flowers with two floral rings, but with the petals wholly or partly united forming a tube or bell
	corolla regular; NOT [corolla irregular]
	stamens 4 or 5; NOT [stamens 8 or 10]
	stamens alternating with corolla lobes, or twice their number; NOT [stamens directly in front of corolla lobes]
	style terminal; NOT [style from centre of lobes of ovary]
	ovary superior; NOT [ovary inferior]
	ovary 1-celled; NOT [ovary 2- or 3-celled]
	ovary with seeds borne on wall of cell; NOT [ovary with seeds born on axis in centre of cell]
	fruit a berry or capsule; NOT [fruit with 4 nutlets]