Plants without leaves. Parasitic on branches or stems of evergreens. =Loranthaceæ.= Not parasitic on trees; roots coral-like. (_Corallorhiza_) =Orchidaceæ.= Plants with leaves. _Leaves parallel-veined._ (A) Flowers small, collected on a spadix. =Araceæ.= (B) Flowers not collected on a spadix. *Flowers regular; corolla lobes 6; stamens 6. (_a_) Leaves grass-like, mostly at the base. Flowers white or greenish. =Melanthaceæ.= Flowers pink. (_Allium_). =Liliaceæ.= Flowers blue. (_Sisyrinchium_). =Iridaceæ.= (_b_) Leaves not grass-like, mostly on the stem. Flowers white or pink. =Convallariaceæ.= Flowers green. =Melanthaceæ.= Flowers yellow or orange. =Liliaceæ.= Flowers red or wine-color. (_Kruhsea_.) =Convallariaceæ.= **Flowers irregular, frequently with broad or inflated lip and spur. =Orchidaceæ.= _Leaves not parallel-veined._ (A) Flowers small, in close heads surrounded by an involucre. Flowers all alike, florets ligulate. =Cichoriaceæ.= Flowers not alike, central ones tubular, marginal usually with rays. =Carduaceæ.= (B) Flowers in umbels at the ends of the stems or branches. Umbels broad, flat or nearly so, flowers white, yellow, or purple. =Apiaceæ.= Umbels round. Flowers greenish; leaves compound. =Araliaceæ.= Flowers white or pink; leaves simple. (_Eriogonum_.) =Polygonaceæ.= (C) Flowers not in umbels. *Flowers regular. (_a_) Flowers with 2 sepals and 5 petals; corolla pink. =Portulacaceæ.= (_b_) Flowers with 3 sepals and 3 petals; seeds triangular. =Polygonaceæ.=