STANDLEY — FLORA OF GLACIER PARK. 259 



Plants not floating on or submerged in water B, BB. 



B. Leaves opposite or whorl ed (a few of the uppermost sometimes alternate); sterna 



leafy. 

 Leaves toothed or lobed. 



Stems Avith slender stinging hairs; flowers green, in cymes . . TJS,TICACEAE(p.326). 

 Stems without stinging hairs; flowers colored or, if green, not in cymes. 

 Flowers in a dense head surrounded by an involucre of bracts, the whole resembling 



a flower; stems not prostrate ASTERACEAE (p. 419). 



Flowers not in a head surrounded by bracts; stems sometimes prostrate. 

 Corolla none or of distinct petals. 



Leaves deeply lobed GERANIACEAE (p. 374). 



Leaves merely toothed. 



Corollanone;stemsprostrate; juice milky . . EUPHORBIACEAE (p. 374). 

 Corolla present, white, green, pink, or purple; stems not prostrate; juice 

 not milky. 

 Leaves thin, not evergreen; petals 2 or 5 . . . ONAGRACEAE (p. 378). 



Leaves leathery, evergreen ; petals 5 PYROLACEAE (p. 388). 



Corolla of united petals. 

 Leaves thick, evergreen; stems prostrate; flowers 2 at the end of a slender 



stalk Linnaea (p. 412). 



Leaves thin, not evergreen; stems usually erect; flowers not in twos. 



Fruit a capsule; corolla 2-lipped .... SCROPHTJLARIACEAE (p. 403). 

 Fruit of 4 nutlets in the bottom of the calyx; corolla 2-lipped or regular. 



Stems prostrate; leaves lobed VERBENACEAE (p. 401). 



Stems erect or nearly so; leaves toothed .... MENTHACEAE (p. 401). 

 Leaves entire. 

 Leaves in whorls of 3 or more, or else a single pair on the stem. 

 Leaves 2 on each stem. 

 Petals 3, very unlike, green; leaves oval, rounded, or kidney-shaped. 



Ophrys (p. 315). 



Petals 5, all alike, pink; leaves lanceolate Claytonia (p. 333). 



Leaves 3 or more on each stem. 



Flowers sessile in the leaf axils; leaves 6 to 12 in a whorl . . . Hippuris (p. 383). 

 Flowers not sessile in the leaf axils; leaves 3 to 6 in a whorl. 



Stems bearing numerous whorls of leaves RUBIACEAE (p. 411). 



Stems bearing a single whorl of leaves. 

 Flowers in a dense head surrounded by 4 white petal -like bracts; leaves 



4 to 6 Cornus (p. 387). 



Flower 1 on each stem, with 3 distinct petals; leaves 3 . . Trillium (p. 314). 

 Leaves opposite by twos, several pairs on each stem. 



Plants parasitic upon the branches of trees LORANTHACEAE (p. 438). 



Plants growing on the ground. 

 Corolla of distinct petals or none. 



Leaves very thick and fleshy CRASSITLACEAE (p. 352). 



Leaves thin, not fleshy. 



Petals yellow; leaves with black dots .... HYPERICACEAE (p. 376). 

 Petals never yellow; leaves not black-dotted. 

 Calyx and corolla absent; flowers sessile in the axils of the leaves. 



CALLITRICHACEAE (p. 375). 

 Calyx and usually a corolla present; flowers not sessUe in the axils of 

 the leaves. 

 Calyx borne on top of the ovary and fruit; petals 2 or 4. 



ONAGRACEAE (p. 378). 

 2048—21 3 



