Ranunculus Ranunculaceae 467 



Flowers large, 1.5-2.5 cm in diameter; petals much exceeding the sepals. 

 Styles in fruit less than 1 mm long, strongly curved; plant introduced, 

 erect; radical and stem leaves 3-7-parted, usually to the base, the divi- 

 sions sessile or rarely on petiolules 13. R. acris. 



Styles in fruit mostly 1 mm long or longer, straight or curved but not 

 hooked except in no. 15 (R. repens var. villosus) ; radical and stem 

 leaves mostly divided to the base and all of the divisions, at least 

 the middle one, stalked. 

 Roots fleshy, much thickened; radical and stem leaves less than 4 cm 

 wide, pinnately cleft or divided, the lobes or divisions narrow, linear- 

 lanceolate; native plant of a dry, sandy habitat, generally less than 

 25 cm high; pubescence of the stems and petioles of our plants 



appressed 14. R. fascicularis. 



Roots not fleshy; plants erect, trailing or creeping, mostly of a wet 

 habitat; radical and lower stem leaves more than 4 cm wide. 

 Styles ending in a minute hook; introduced, creeping plants mostly of 

 lawns and waste places. 



Pubescence spreading 15. R. repens var. villosus. 



Pubescence appressed. (See excluded species no. 242, p. 1049.) 



R. repens. 



Styles straight or slightly curved, not hooked at the tip. 



Plants erect or ascending, never trailing and rooting at the nodes or 

 tips, usually densely spreading-pubescent; styles 1.5-2 mm long. . . 



16. R. hispidus. 



Plants erect at first, later trailing and becoming prostrate and root- 

 ing at some of the nodes or at the tips. 

 Stems and petioles of the later radical leaves upwardly appressed- 



pubescent or nearly glabrous 17. R. septentrionalis. 



Stems and petioles of the later radical leaves spreading-pubescent. 



Pubescence of the stem and of the petioles of the later radical 



leaves usually not dense and not retrorse; fruiting heads 



globose with about 20 achenes; styles 1.5-2 mm long 



17a. R. septentrionalis forma. 



Pubescence of the stem and of the petioles of the later radical 

 leaves very dense and retrorse at least on the lower parts; 

 mature heads longer than wide (not measuring the styles), 

 with up to 50 achenes to a head; styles 2.25-3 mm long, 

 rarely shorter; plants robust, few-flowered, soon becoming 



prostrate and rooting at the nodes 



17b. R. septentrionalis var. caricetorum. 



1. Ranunculus flabellaris Raf. (Ranunculus delphinifolius Torr.) Map 

 957. Somewhat frequent in ponds, sloughs, and dredged ditches in the 

 lake area, becoming infrequent to very local or absent from the southern 

 part of the state. When its habitat becomes dry during the summer 

 months, this species assumes a terrestrial form. This form has been 

 named Ranunculus flabellaris f. riparius Fern. (Rhodora 38: 171. 1936.) 

 (Ranunculus delphinifolius var. terrestris (Gray) Fern.) Its appearance 

 is somewhat different from the aquatic form and I believe it has been 

 the source of several reports for Ranunculus Purshii. 



Central Maine, Ont, Mich., southw. to N. C. and Ark. 



2. Ranunculus trichophyllus Chaix var. typicus Drew. (Rhodora 38: 

 18-29. 1936.) (Ranunculus aquatilis var. capillaceus DC. and Batrachium 

 trichophyllum (Chaix) F. Schultz.) Map 958. This is a species found 



