440 



WEED FLORA OF IOWA 



Small-flowered Crowfoot {Ranunculus ahortivus L.)- 



Achene flattened-circular, with 2 convex faces, orange-brown in 

 color, smooth and shining, very slightly impressed with wrinkles'; 

 remnant of style present as a short curved point on margin. 



Figure 285A Figure 285B 



Fig. 285. A. Small-flowered Crowfoot {Ranunculus abortivus). a, 



enlarged ; b, end view ; c, achenes natural size. 

 B. Tall Buttercup (Bdnunculus acris). a, b. different views of seed; 



section ; d, natural size. 



(After HlUman, Bull. Mich. Agr. Exp. Sta.) 



achenes 

 c, cross 



Tall Buttercup (Ranunculus acris). 



Carpel 1-ovuled; achene flattened, tipped by remnant of curved 

 style, one-tenth to one-eighth in. long; color greenish to brownish; 

 surface apparently smooth, minutely pitted; scar minute, in a 

 whitish depression at base of achene. 



PAPAVERACEAE, POPPY FAMILY. 



Pop-py {Papa/ifer somniferum h.) . 



Seed about 1 mm. in length, kidney-shaped, one end being slightly 

 larger than the other; hilum and chalaza in a notch, connected by 

 a short raphe; surface covered with fine, beautiful reticulations; 

 embryo straight; considerable endosperm. 



Figure 286A 



P'lGS. 286. A. Poppy (Papaver somniferum) 

 B. Prickly Poppy (.Argemone intermedia). 



(A, after Winton. B, drawing, C. M. King.) 



Figure 286B 

 To the left embryo of seed. 



