SOME SEGREGATES OF OENOTHERA. 129 



of which have not yet been isolated. The 0. biennis which ex- 

 tends over a large part of Europe is still another form, or per- 

 haps series of forms. The small flowers and the short style 

 ensuring self-pollination are characters easily distinguish- 

 ing it from all the derivatives of 0. Lamarckiana and 

 0. grandi flora. 



Oenothera Oakesiana (Robbins) S. Watson. 



Vail in "Mutations, variations and relationships of the Oenotheras", 

 (Carnegie Pub. 81 : 70. pi. 15-17). 1907. 



This species is very close to 0. biennis, the main differ- 

 ences enumerated by Robbins being the possession of spread- 

 ing sepal tips, a longer and more taper capsule and larger 

 seeds. The rosette leaves are oblong-ovate, obtuse, taper- 

 ing to a white, margined petiole, dull or pale blue-green, 

 nearly glabrous; later rosette leaves more or less strigose- 

 pubescent, narrowly lanceolate, shallowly toothed at acute 

 apex, more deeply notched at the slender, tapering base. 

 Stem leaves narrowly lanceolate, acute and tapering at each 

 end. 



Oenothera muricata Linnaeus. 



Flora Danica. pi. 1752. 1823.— Reichenbach, Icon. Fl. Ger. et Helv. 

 23. pi. 21. 1898. — Vail in " Mutations, variations and relationships of 

 the Oenotheras", p. 73. pi. 21, 22. 1907. 



The flowers are somewhat smaller than in 0. biennis, and 

 the style shorter so that the stigma is below the stamens in 

 the bud; buds pubescent with apprcssed and spreading hairs; 

 rosette persisting when the plant is mature. Rosette leaves 

 approximately denticulate, more deeply so toward the base, 

 with a broad white-margined petiole. Stems angled, turn- 

 ing red and outer bark splitting into shreds at maturity. 



Oenothera parviflora Linnaeus. 



Meerburg, Plantae rariores. pi. 84. 1789. Vail in " Mutations, varia- 

 tions and relationships of the Oenotheras", p. 71. pi. 18-20. 1907. 



Flowers very small; petals 8 mm. long; stigma situated 

 below the stamens in the bud; rosette leaves long and 

 slender, lanceolate or oblong-lanceolate, acutish, dark green 

 and shiny; buds club-shaped with spreading sepal tips. 



