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- 

 crested. 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 

 the 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 

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

 in age: capsule with rather strong, smuately lobed ridges. The species as here 

 described comprises most of the forms long known in literature and in herbaria 

 as Oenothera caespitosa. (P. hirsutus Rydb. 1. c. 31: 571. 1904.) Frequent 

 throughout our range. 



5. Pachylophus eximius Gray, PI. Fendl. 45. 1848. More or less caules- 

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



