Philadelphicum: Answers to key questions leading to this genus, from Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton.

	Flowers terminal, either single or grouped in an umbel, raceme or panicle.  NOT [Flowers axillary, suspended on delicate stalks from leaf axils, either singly or in few-flowered clusters (leaves small and scale-like in Asparagus).]
	Inflorescence a single flower or an umbel.  NOT [Inflorescence a raceme or panicle.]
	Leaves cauline, linear to lanceolate or ovate, not grass-like.  NOT [Leaves basal, long, narrow, grass-like.]
	Flowers erect (in ours), large (over 4 cm long), brightly-colored; fruit a capsule.  NOT [Flowers nodding, small (to 1.5 cm long), creamy-white; fruit a berry.]

Liliaceae: Answers to key questions leading to this family, from Lilies, Irises & Orchids of Saskatchewan by Vernon L. Harms and Anna L. Leighton. 

Ovary positioned above the attachment point of the other flower parts (ovary superior) or with the other parts attached partway up the ovary wall (ovary partly inferior) or, if ovary positioned below the attachment point (ovary inferior), then stamen number 6 (Hypoxis); stamens 3 or 6 (rarely 4); fruit a capsule or berry.  NOT [Ovary positioned below the attachment point of the other flower parts (ovary inferior); stamens 1-3; fruit a capsule.]