348 IOWA ACADEMY OF SCIENCE 



63. Cuscuta Gronovii "Willd. Gronovius Dodder. L., 1.4 — 

 1.9 mm. W., 1.2 — 1.8 mm. C, dark brown, granular, dull, 

 sometimes yellowish. S., almost globular, closely resembling 

 clover seed but more close and compact ; embryo in a spiral ; 

 without a noticeable concavity at the scar. 0.. very common 

 in lowlands. Native. 



64. Cuscuta epithymum Murr. Clover Dodder. L., .6 — 1.2 

 mm. W., .7 — 1. mm. C, variable, usually dusty light brown 

 to black. S.j irregularly spherical with distinct shallow pits 

 when seen through a hand microscope ; usually with a fairly 

 distinct sear at point of attachment; often with two adjacent 

 flattened areas near the scar. 0.. quite common in clover and 

 alfalfa. 



65. Cuscuta arvensis Beyrich. Field Dodder. L., 1. — 1.8 

 mm. W., .8 — 1.5 mm. C, quite light pinkish yellow or flesh 

 colored, rarely dark brown ; with a grayish dusty appearance 

 under the microscope. S., irregularly spherical; almost in- 

 variably with two or three adjacent flattened areas on one side 

 and with the other side rounded regularly. Surface of a gran- 

 ular appearance. Embryo curled. Surface not prominently 

 pitted as in C. epithymum Murr. Much lighter in color than 

 C. Gronovii Willd. 0., found occasionally in red clover. In- 

 troduced from Europe. 



66. Lappula' virginiana (L.) Greene. Stickseed, Beggar's 

 Lice. L., 3. — 4.4 mm. W., 2. — 2.9 mm. C, dark brown to 

 black. S., broadly ovate with spines on one side and about 

 four ridges radiating from an ovate ridge on the other, spines 

 with bulbous tips. 0., abundant along roadsides and found 

 as an adulterant of red clover seed. Native. 



67. Lithospemtum arvense L. Corn Gromwell, Wheat Thief, 

 Red Root, Stoneseed. L., 2.5—3.8 mm. W.. 1.8—2.2 mm. C, 

 light gray-brown with a dark area at the base, dull. S., tur- 

 binate or somewhat spherical with a long drawn out protuber- 

 ance at the apical end and a slight keel on the back surface *, 

 base truncate with two minute tubercles visible to the naked 

 eye; very hard. 0., found in seed of red clover, alfalfa, ce- 

 reals, grasses, etc. Naturalized from Europe. 



68. Verbena urticae folium L. Nettle-leaved Vervain. L., 

 1.5- — 2.2 mm. W.. .5 — .9 mm. ('.. dull dark reddish brown 

 with a pronounced white spot at one end. S.. oval to oblong, 



