ONAGRACEAE (EVENING PRIMROSE FAMILY) 337 



cm. long, slender-stalked. Frequent in the mountains from Montana to 

 Colorado. 



11. Epilobium ovatifolium Rydb. Bull. Torr. Bot. Club 31: 567. 1904. 

 Plant 2-6 dm. high, propagating by turions: stem glabrous except the de- 

 current lines which are more or less crisp-hairy, especially above: leaves 

 sessile or nearly so, ovate or ovate-lanceolate and acute, or the lowest oval 

 and obtuse, 3-4 cm. long, entire or denticulate, glabrous: petals purple or 

 rarely rose, 5-7 mm. long: pods 5-6 cm. long, 1.5-2 mm. in diameter, sessile, 

 more or less crisp and glandular-hairy: seed a little over 1 mm. long, abruptly 

 contracted above, but without neck; coma white, about 6 mm. long. (E. 

 Drummondii latiusculum Rydb. Mem. N. Y. Bot. Card. 1: 276. 1900; E. 

 brevistylum; E. Halleanum; and E. glandulosum probably, but only as to 

 plants of our range.) Colorado to Montana. 



12. Epilobium adenocaulon Hausskn. Oesterr. Bot. Zeitschr. 29: 119. 

 1877. With upcurving branches throughout, the inflorescence, capsules, etc., 

 very glandular-pubescent and with few if any incurved hairs: leaves 5 cm. 

 or, exceptionally, 7 cm. long, frequently erect, elliptical to mostly ovate- 

 lanceolate, obtuse, only slightly serrulate or denticulate, abruptly rounded 

 to short-winged petioles, rather pale green and glossy, glabrous except the 

 uppermost, which are gradually reduced and but slightly rugose: flowers very 

 numerous, nodding at first: petals 3-5 mm. long, rosy: fruiting peduncles 

 slender, mostly short: seeds obovoid, abruptly short-beaked; coma white. 

 E. coloratum. (E. rubescens Rydb. 1. c. 568.) The commonest of our species, 

 variable; wet banks everywhere. 



13. Epilobium perplexans Trel. in Herb, ex Tweedy (1900), Greene (1902). 

 Slender, subsimple or with few ascending remotely leafy branches, less glan- 

 dular, the inflorescence sometimes canescent with incurved hairs: leaves scarcely 

 5 cm. long, divergent, lanceolate, rather obtuse and sparingly undulate- 

 serrulate, thin and light green, the upper acutely tapering to slender some- 

 times elongated petioles. (E. adenocaulon perplexans Trelease, Rep. Mo. Bot. 

 Card. 2: 96. 1891; E. stramineum Rydb. 1. c., in part; E. Palmeri Rydb. 1. c. 

 569.) Frequent in our range. 



6. ONAGRA Adans. EVENING PRIMROSE 



Annual or biennial herbs, with mostly erect stems. Leaves alternate, un- 

 dulate or toothed. Buds erect. Flowers yellow, nocturnal, in terminal 

 spikes. Calyx-tube elongated. Ovary 4-celled; ovules in 2 or more rows, 

 horizontal. Capsule 4-angled, more or less tapering, opening loculicidally. 

 Seeds prismatic-angled. Oenothera in part. 



Calyx-tube slender, 2.5-5 cm. long. 



Plant somewhat strigose; petals yellow, 1-2 cm. long . . . 1. O. strigosa. 



Plant somewhat hirsute; petals yellow or pinkish, 2.5-4 cm. long . 2. O. Hookeri. 



Calyx-tube stout, 5-10 cm. long . . . . . . . . 3. O. Jamesii. 



1. Onagra strigosa Rydb. Mem. N. Y. Bot. Card. 1: 278. 1900. Strigose 

 and somewhat villous above with grayish hairs, 4-10 dm. high: leaves various, 

 the basal obovate or spatulate, obtuse; stem leaves oblanceolate to lanceo- 

 late, 5-10 cm. long or the upper shorter, acute, undulate: spike leafy-bracted, 

 many-flowered: calyx-segments with short free tips: corollas pure yellow, 

 3-4.5 cm. broad: capsules 2.5-3 cm. long. Oenothera biennis. Along the 

 eastern base of the mountains to Montana, S. Dakota, and Nebraska. 



2. Onagra Hookeri (T. & G.) Small, Bull. Torr. Bot. Club 23: 171. 1896. 

 Stems erect, usually stout and mostly simple, canescently pubescent and more 

 or less hirsute: leaves lanceolate to ovate-lanceolate, acute or acuminate, re- 

 pandly denticulate, the lowest petioled: flowers sessile, in a leafy spike: calyx 

 villous, the tube twice the length of the ovary, rather shorter than the slightly 

 acuminate segments: petals obcordate, about 3 cm. long: stigma linear, 

 somewhat thickened: capsule more or less pubescent. From the Rocky 

 Mountains to the Pacific coast. 



ROCKY MT. BOT. 22 



