r 



108 MISSOURI BOTANICAL GARDEN. 



atives, — including the species on which the genus was 

 founded by Jussieu, — occupy the corresponding part of 

 the South American continent ; but the genus appears to be 

 entirely absent from the intervening country. None of the 

 species are truly alpine, though several of them reach up 

 to considerable altitudes in the higher mountains ; never- 

 theless the indication is that the former distribution of the 

 genus was continuous along the backbone of both North 

 and South America. Plants of this distribution are often 

 represented also across the North American continent in 

 high latitudes, and not infrequently they occur likewise in 

 Europe, where they enjoy a similar arctic-alpine distribu- 

 tion. In the present case, however, the prototype of the 

 genus appears to be of rather recent differentiation from 

 Oenothera, which is of wide American distribution (one 

 species, Tasmanian, according to Bentham and Hooker), of 

 which genus it represents an accentuated mountain type. 



The principal revisions of our species appear in Torrey 

 & Gray, Fl. N. A. i. 512; Watson, Bot. Calif, i. 221; 

 Coulter, Man* Rocky Mt. Bot. 103; and Greene, Flora 



Franciscana, 218. 

 Index. 370. 



Watson 



SYNOPSIS. 



Seeds canescent with appressed hairs. 



Flowers small, the petals about 1 mm. long G. lasiospermum. 



Flowers large, the petals 3 to 6 mm. long G. eriospermum. 



** Seeds glabrous, either smooth or low papillate. 

 ^- Much forked above, mostly remotely leafy : stigma rather small : 

 pedicels filiform, elongated: capsules subclavate, mostly toru- 

 lose : seeds rather few, suberect, large, mostly dark colored. 

 Large flowered, the petals 3 to 6 mm. long: seeds about 1.5 mm- 



long 



G. diffusum. 



Small flowered, the petals 1 to 2 mm. long: seeds 1 to 1.5 mm. long. 



G. ramosissimum. 



Subsimple or paniculately branched, especially toward the base, 

 densely leafy : stigma large, capitate : pedicels short or almost 

 wanting : capsules neither clavate nor conspicuously torulose : 

 seeds numerous, small, pale. 



Capsules narrowly linear, with suberect seeds G. caesium. 



Capsules broadly oblong, flattened contrary to the septum, with 

 very oblique seeds a. pumilum. 



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