Froelichia 



Amaranthaceae 



431 



o lo 



Map 884 



Acnida tamariscina (Nutt.) Wood 



3. Acnida subnuda (Wats.) Standley. (Acnida tuberculata var. sub- 

 nuda S. Wats.) Map 886. My specimens are from the muddy slopes and 

 bars of our larger streams. This species is closely related to the preceding 

 one and is separated from it primarily by its prostrate habit and by its 

 larger seed. 



Ont. to S. Dak., southw. to Tenn. 



2332. FROELICHIA Moench 



Plants much divided near the base, the erect portion usually not much longer at 

 maturity than the long, lower, and often prostrate branches; wings of the flattened 

 calyx tube at maturity about 1 mm wide and divided usually to the base into 

 about 6 or 7 spinelike teeth, the tube also provided at the base with tubercles, 



usually one on one side and two on the opposite side 1. F. gracilis. 



Plants erect, tall, not divided near the base, sparingly branched; wings of the flattened 



calyx tube at maturity about 1 mm wide and not divided to the base but more or 



less deeply dentate, the tube at the base with one or both sides with a tubercle or 



tubercular lines. 



Pubescence of the upper part of the stem of very short, brownish hairs. (See 



excluded species no. 207, p. 1043.) F. floridana. 



Pubescence of the stems white and woolly 2. F. campestris. 



1. Froelichia gracilis (Hook.) Moq. Map 887. In 1930 I found a 

 few plants of this species along the Chicago & Eastern Illinois Railroad 

 at the Duncan Switch about 4 miles south of Vincennes. The soil along 

 the railroad here is almost a pure sand. By the fall of 1933 it had spread 

 for a quarter of a mile and formed a complete stand at the switch and 

 for several hundred feet to the north of it. This species will probably be- 

 come a weed in the sandy area of this part of the country. In 1933 I found 

 two small colonies in ballast along the railroad in the first mile east of 

 Dana, Vermillion County. In 1933 Paul Weatherwax found a large colony 

 in ballast along the railroad half a mile south of Worthington, Greene 

 County. In 1937 Charles M. Ek found scattered plants in cinder soil in 



