462 COBB AND BARTlvETT: INHERITANCE IN OENOTHERA 



than the leaves, sordidly tomentose-pilosulous, 1.8 to 2.5 cm. long, 

 1.5 to 3 cm. wide; pedicels i to 1.5 mm. long; perianth 2.5 m.m. long, 

 soon deciduous, sordidly pilosulous-tomentulose both sides, the tube 

 obscure, the segments subequal, oval, rounded at tip; stamens of 

 series I 2.2 mm. long, the stout filaments 0.8 mm. long, pilose on 

 back and down midline within, the 2 -celled ovate eciliate sparsely 

 papillose anthers i mm. long, the quadrate obtuse appendage 0.3 

 mm. long; those of series II similar, 2.4 mm. long (filament i mm., 

 anther i.i mm., appendage 0.3 mm.); those of series III 2.2 mm. long, 

 the filaments slender, pilose, i mm. long, bearing at base 2 cordate- 

 globose short- stipitate glands essentially as long, the extrorsely 2 -celled 

 anther 0.8 mm. long, the thick truncate appendage 0.4 mm. long; 

 staminodes i.i mm. long, deltoid, acute, pilose on back and on the 

 short, broad stipe; ovary glabrous, globose-ovoid, 1.5 mm. long, nar- 

 rowed into the 0.5 mm. long style and oblique stigma. 



Type in the U. S. National Herbarium, no. 578438, collected on the 

 Volcan de Poas, Costa Rica, altitude 2300 meters, March 31, 1907, 

 by H. Pittier (no. 2040). 



Hufelandia ovalis is related to H. anay and H. pendula. From the 

 former it may be easily distinguished by its much smaller, finely prom- 

 inulous-reticulate leaves, its longer filaments, and its larger floral glands. 

 From the latter it differs in its thicker more finely reticulate leaves, 

 its dense ovoid panicle, and its longer filaments. 



GENETICS. — On Mendelian inheritance in crosses between 

 mass-mutating and non-mass -mutating strains of Oenothera 

 pratincola.^ Frieda Cobb and H. H. BartIvETT. 

 A former paper^ has dealt with the striking difference in muta- 

 bility between certain strains of Oenothera pratincola that are 

 morphologically identical. The strains in question were de- 

 rived from seeds of wild plants collected in 191 2 at Lexington, 

 Kentucky. Several of them, typified by the strain designated 

 as Lexington C, show only a moderate degree of mutability. 



1 Papers from the Department of Botany of the University of Michigan, No. 160. 

 This paper is pubHshed as presented at the Pittsburgh (19 17) meeting of the Botan- 

 ical Society of America. It has been lying in manuscript since the fall of 191 7. 

 The data upon which it is based have since been greatly amplified. The new re- 

 sults are based upon much larger cultures and verify those here presented, but are 

 not yet ready for pubhcation. A preliminary abstract has appeared elsewhere. 

 (Proc. Mich. Acad. Sci. 1918: 151. 1919-) 



- Bartlett, H. H. Mass mutation in Oenothera pratincola. Bot. Gaz. 60: 

 425-456. 1 915. 



