ONAGKACEAE 139 



On mud flats along the Missouri River, especially near Courtney. August- 

 October. 



3. EPILOBIUM L. WILLOW HERB. 



Calyx tube somewhat prolonged beyond the ovary. Parts of the flowers 

 in fours. Capsules linear. Flowers in upper axils. 



Leaves linear. 1. E. lineare. 



Leaves lanceolate. 2. E. coloratum. 



1. E. lineare Muhl. l-2 high, canescent : leaves entire, short-peti- 

 oled. In a bog two miles west of Sibley. Uncommon. July-October. 



2. E. coloratum Muhl. l-3 high, hoary-pubescent : leaves sharply 

 serrulate, short-petioled : seeds beakless, the coma with a slight reddish 

 tinge. In low grounds near Leeds, Grain Valley, Courtney and Sibley. 

 Locally common. August-October. 



4. OENOTHERA L. YELLOW EVENING PRIMROSE. 

 Flowers nocturnal. Flower parts in fours. Stamens equal in length. 

 Capsules elongated-cylindric. Seeds horizontal or ascending. Flowers 

 spicate, or axillary in No. 1. 



Stems decumbent and spreading. 1. 0. laciniata. 

 Stems tall and erect. 



Petals acute-pointed. 2. 0. rhombipetala. 

 Petals emarginate. 



Capsules little pubescent. 3. 0. Uennis. 



Capsule strongly pubescent. 4. 0. strigosa. 



1. O. laciniata Hill. 1 or less high, appressed -pubescent : leaves 

 sinuate-toothed or pinnatifid : flowers 3 // -12 // broad : capsules linear, 

 hairy. Rather common in sandy soil in the Missouri River bottoms. 

 May-July. 



Var. grandis Britton. Flowers 24 // -30 // broad. Occasionally adven- 

 tized near Sheffield and Leeds. May-July. 



2. O. rhombipetala Nutt. 2-4 high, appressed-pubescent : leaves 

 linear- lanceolate, somewhat denticulate : flowers \\' broad, in long leafy 

 spikes. Sandy bottoms from Sheffield to Courtney. Infrequent. June- 

 September. 



3. O. biennis L. 2-5 high, pubescent : leaves lanceolate to oblong- 

 lanceolate, repand-denticulate : flowers \\ f broad : capsules \\ f or less 

 long, appressed-pubescent. Common in dry soil throughout. Very vari- 

 ables. July-September. 



4. O. strigosa (Rydb.) Mackenzie & Bush, n. comb. Strongly resem- 

 bles the last, but stem strigose and capsules copiously pubescent. Not 

 uncommon throughout, especially in the southern part. (0. liennis 

 strigosa Rydb. ) 



5. HARTMANNIA Spach. 



Flowers diurnal. Parts in fours. Stamens unequal. Stigma 4-cleft. 

 Capsules club-shaped, 4-ribbed and 4-winged. 



