126 MISSOURI BOTANICAL GARDEN. 



GENERAL KEY. 



Petals cruciate, narrow and linear. 0. cruciata. 



This probably includes a number of sub-forms. Cruciate varieties 

 of 0. Lamarckiana and of European O. biennis, as well as of other 

 forms, are also known. See DeVries, Die Mutationstheorie. 2 : 593- 

 633. 

 Petals broad; flowers small, about 3 cm. in diameter; petals about 13-15 

 mm. long; style short, so that the anthers surround the stigma lobes 

 and ensure self-pollination in the bud. 



Sepal tips appressed; capsule not taper, often stouter near 



the middle. 0. biennis and its segregates. 



Sepal tips spreading; capsule long and taper. O. Oakcsiana. 



Petals broad ; flowers smaller than in O. biennis; stigma situated below the 



anthers in the bud. 



Petals 13-15 mm. long; rosette persisting when the plant 

 is mature. 0. muricata. 



Flowers larger than in O. muricata; rosette persisting. 



0. ammophilu. 

 Flowers very small; petals 8 mm. long; rosette not persisting. 



O. parviflora. 

 Petals broad; flowers large; style long (except in 0. brevistylis, which 

 has a very short style), protruding the stigma beyond the stamen* 

 and preventing self-pollination before the bud opens. 



Flowers large, about 7 cm. or more in diameter; style very long, 

 so that the stigma protrudes from the bud before the latter 

 opens (as is often true also of the buds of 0. Lamarckiana 

 and 0. grandiflora in the latter part of the season); calyx 

 glabrous. Rosette leaves nearly glabrous, long, linear or 

 linear-spatulate, sinuate. 0. argillicola. 



Flowers about 7 cm. in diameter; style short, so that the stigma 

 is surrounded by the anthers, as in 0. biennis. O . Simsiana. 

 Flowers about 7 cm. in diameter (or larger in O. gigas); style 

 longer than in 0. biennis, so that the stigma is protruded be- 

 yond the stamens, but enclosed in the bud, except in some 

 cases in the later and smaller buds of the season. 

 Buds smooth, with an inconspicuous pubescence of short hairs; 

 sepals thin and papery; bud-cone slender, about 6 to 7 mm. 

 in diameter at the base, and rounded owing to thinness of 

 sepals and less prominence of the median longitudinal ridge 

 of the sepals; sepal tips usually long and very slender. Red 

 glands on stem present or absent. 



O. grandiflora and its segregates. 

 Buds papillate, with numerous long and short hairs ; sepals some- 

 what thicker than in O. grran<^;i^om and median ridge more 

 prominent, giving a characteristic squarish appearance to 

 9 



