ONAGRACEAE (EVENING PRIMROSE FAMILY) 335 



serted; ovary and capsule minutely glandular-pubescent. Utah, and prob- 

 ably in northwestern Colorado. 



4. EPILOBIUM L. WILLOW HERB 



Herbs or sometimes shrubby plants, with alternate or opposite leaves, and 

 axillary or terminal, solitary or racemose flowers. Calyx linear, produced be- 

 yond the ovary, the limb 4-parted, deciduous. Petals 4, mostly obovate or 

 obcordate. Stamens 8; anthers oblong or linear, short. Ovary 4-celled; 

 united styles slender or filiform; stigma club-shaped or 4-lobed. Capsule 

 elongated, 4-sided, 4-celled, loculicidally dehiscent by 4 valves. Seeds small, 

 numerous, with a tuft of hairs (coma) at the summit. 



Annual . . . . . ... . . 1. E. paniculatum. 



Perennials. 



Stigma deeply 4-lobed or 4-cleft; flowers cream-colored . . 2. E. suffruticosum. 

 Stigma entire or only notched; flowers never yellow. 

 Seeds smooth or nearly so under the microscope. 

 Leaves medium size, more or less toothed. 



Flowers violet . . . . . . . 3. E. Hornemannii. 



Flowers white , . . . . . . . , 4. E. alpinum. 



Leaves small, entire or nearly so; plants 3-10 cm. high . 5. E. anagallidifolium. 

 See Is papillate-roughened under the microscope. 

 Plants not glandular; leaves linear. 



Foliage and lower part of the stem glabrous . . 6. E. wyomingense. 



Foliage and stem crisped-hairy . . . . 7. E. lineare. 



Plants glandular above at least. 



Plants usually less than 3 dm. high. 



Leaves numerous and approximate; plants low, less 



than 2 dm. high. 

 Plants erect, not caespitose . . . . ^ . 8. E. saximontanum. 



Plants assurgent; densely caespitose . . 9. E. clavatum. 



Leaves fewer, remote, suberect; plants 2-3 dm. high, 



with turions (if any) not sessile. 



Leaves narrow, somewhat petioled . . . 10. E. Drummpndii. 

 Leaves oblong to ovate, sessile . . . . 11. E. ovatifolium. 



Plants tall, 4-10 dm. high. 



Usually freely branched, leafy, very glandular; 



petioles short, winged . . . . . 12. E. adenocaulon. 



Usually subsimple, less leafy and less glandular; 



petiole slender 13. E. perplexans. 



1. Epilobium paniculatum Nutt. T. & G. Fl. 1: 490. 1840. Annual, 

 slender, 3-6 dm. tall, loosely branched, glandular-pubescent above: leaves 

 alternate, linear to linear-lanceolate, 2.5-7.5 cm. long, denticulate or nearly 



entire, attenuate into slender- winged petioles: calyx often purple, its tube 

 funnelform, 2-3 mm. long, shorter than the lanceolate segments: petals cune- 

 ate, notched, 6-8 mm. long, violet: capsules ascending, linear-fusiform, 2-3 

 cm. long, curved: seeds obovoid, 2 mm. long, black, slightly papillose. Ap- 

 parently in most parts of the western United States. 



2. Epilobium. suffruticosum Nutt. 1. c. 488. Stems woody and freely 

 branched at base, 10-16 cm. high, minutely canescent throughout or at length 

 glabrate below: leaves numerous, less than 2 cm. long, mainly opposite, broadly 

 lanceolate, acutish, entire, narrowed below but hardly petioled, thick, with 

 inconspicuous veins: flowers rather few, in the axils of the scarcely reduced 

 upper leaves: calyx-tube broadly funnelform: petals 6-8 mm. long: capsule 

 20-25 mm. long, short-stalked: seeds 1 mm. or more long, coma long and 

 very dingy. Western Wyoming to Montana and Oregon. 



3. Epilobium Hornemannii Reichenb. Icon. Crit. 2: 73. 1824. Mostly 

 2-3 dm. high, ascending, unbranched, somewhat crisp-hairy in the inflores- 

 cence, or slightly glandular at top, otherwise glabrate: leaves about 25 mm. 

 long, subascending, elliptical-ovate, mostly very obtuse, nearly entire to re- 

 motely serrulate, the lower cuneately narrowed, the upper usually abruptly 

 rounded to the short petioles: flowers rather few, nearly erect: petals 5-8 mm. 

 long, Jilac to deep violet: capsules as much as 5 cm. long, slender, erect, on 

 slender peduncles about equaling the gradually reduced subtending leaves: 

 seeds rather abruptly short-appendaged, from nearly smooth to very rough. 

 Throughout our range to California and British Columbia. 



