340 ONAGRACEAE (EVENING PRIMROSE FAMILY) 



than the tube. Petals white or pink. Capsules basal, woody, pyramidal, their 

 angles retuse or obtuse, transversely wrinkled, and sometimes tuberculate- 

 erested. Seeds sessile, in 1 or 2 rows, deeply furrowed along the raphe. This 

 has been considered a monotypic genus, and it must be said that the following 

 species are far from sharply distinct. Oenothera in part. 

 Wholly glabrous throughout; calyx-tube several times longer than its 



Capsule tuberculate-crested on the angles; flowers large, surpassing 



the leaves 1. P. caespitosus. 



Capsule with smooth rounded angles; flowers small, surpassed by 



the leaves 2. P. glaber. 



More or less pubescent or hirsute. 



Strictly acaulescent; calyx-tube only twice as long as its lobes . 3. P. montanus. 

 Acaulescent or caulescent; calyx-tube three to several times as long 



as its lobes. 

 Capsule sessile. 



Acaulescent or nearly so, sparingly pubescent . . . . 4. P. macrpglottis. 

 Acaulescent and conspicuously pubescent or villous . . . 5. P. eximius. 

 Capsule stipitate; caulescent 6. P. marginatus. 



1. Pachylophus caespitosus (Nutt.) Raimann, Eng. & Prantl. Nat. Pfl. 

 Fam. 3 7 : 215. 1893. Wholly glabrous, stemless or subcaulescent: leaves 

 lanceolate, acute, repandly toothed or nearly entire, attenuate into a long 

 margined petiole: tube of the calyx 4 times as long as the carinate, acumi- 

 nate segments: corolla very large, 6-8 cm. broad; petals obcordate, white, 

 with yellowish veins, reddish in withering, longer than the declined stamens 

 and style: capsules nearly sessile, oblong-conical, conspicuously doubly 

 tuberculate-cristate along the sutures. Oenothera caespitosa. "The typical 

 form only on the upper Missouri in Dakota and Nebraska." Reported doubt- 

 fully from Wyoming and Colorado. 



2. Pachylophus glaber A. Nels. Bull. Torr. Bot. Club 31: 242. 1904. 

 Acaulescent and completely glabrous throughout: root thick, semifleshy, 

 caespitosely branched at summit: leaves crowded, nearly linear, 7-12 cm. 

 long, remotely and irregularly toothed, tapering to both ends, acute; slender 

 petiole about half as long as the blade: flowers not equaling the leaves: the 

 calyx-tube slender, 1 dm. or less long; calyx-lobes about 2 cm. long: petals 

 somewhat inequilateral, broad, deeply cleft-cordate, about 2 cm. long: fruits 

 small, 12-15 mm. long, strictly basal, not tubercled and but slightly angled. 

 The region of the Platte, in Wyoming. 



3. Pachylophus montanus (Nutt.) A. Nels. 1. c. 26: 128. 1899. Root 

 large, woody with fleshy cortex, crowns one or more, strictly acaulescent : leaves 

 3-8 cm. long, oblong or oblanceolate, irregularly pinnately toothed, from 

 sparsely hirsute, to green and glabrous on the faces, canescently hirsute on 

 tne margins and midrib: flowers few: calyx-tube equaling or shorter than 

 the leaves, hirsute-pubescent; segments pinkish, lanceolate, glabrous but 

 for a pubescent line down the middle: petals white (drying pink), broadly 

 obcordate, 2-3 cm. long: capsule sessile, oblong or narrowly ovate, obscurely 

 tubercled on the obtuse sutures, 15-20 mm. long: seeds in two rows, brown 

 or nearly black, irregularly obovate. On otherwise naked red clay soils; 

 Colorado to Montana. 



4. Pachylophus macroglottis Rydb. Bull. Torr. Bot. Club 30: 259. 1903. 

 Acaulescent or nearly so: leaves 8-15 cm. long, tapering into a margined 

 petiole; blades broadly oblanceolate, acute, sinuate-dentate, more or less 

 pubescent, and villous-ciliate on the margins and the veins: calyx-tube long 

 and slender, 14 cm. long, sparingly villous or nearly glabrous, gradually 

 widening into a funnelform throat, more than twice as long as the lanceolate 



petals obcordate, about 3.5 cm. long, at first white but turning pink 

 in age: rapsuli- \\ith rather strong, sinuately lobed ridges. The species as here 

 <1< -.-crihcd comprises most of the forms long known in literature and in herbaria 

 as Ot-nntln-rn rm .s/,,/o.sa. (P. hirsutus Rydb. 1. c. 31: 571. 1904.) Frequent 

 throughout our range. 



f>. Pachylophus eximius Gray, PL Fendl. 45. 1848. More or less caules- 

 cent, the stem rather fleshy and leafy: leaves 1-2 dm. long, pinnatifid-sinuate, 





