No. 586] 



ANNUAL SUNFLOWERS 



615 



Thus we have at the most nine species, which can prob- 

 ably be reduced to five. They belong to the region which 

 used to be marked in old geography books as the " Great 

 American Desert," though members of the dcbilis group 

 extend along the Gulf States to Florida. The dominant, 

 widely distributed form is lenticalaris , a plant of sandy 

 river-bottoms and similar places, which has spread as a 

 weed in cultivated areas. Prior to the era of cultivatioD- 

 it is probable that H. petiolaris occupied a greater area, 

 at least in acreage. At the present time H. lenticularis 

 is common in California, but I suspect that it has been 

 introduced into the Pacific coast region by man. 



In order to give an idea of the cultivated forms of our 

 group, I have made a table from Sutton's Catalogue for 

 1915. 



Silver-leaved (argophyllus-type) ; rays yellow; 



