104 
IOWA ACADEMY OP SCIENCES. 
T. nivale Riddell. Several plants were collected in 1895 by 
Miss Etna Burrette. 
XYRIDACE^. 
Xyris flexuosa Muhl. Low prairies, apparently rare. 
COMMELINACE^. 
Tradescantia virginica L. Low prairies, common. Flowers 
frequently rose-colored or nearly white. 
JUNCACE^. 
Juncus tenuis Willd. Prairies, woods and pastures, abundant. 
J. nodosus L. Low, sandy ground, common. 
TYPHACE^. 
Typha latifolia L. Sloughs, common. 
Sparganium eurycarpum Engelm. Swamps, infrequent. 
S. simplex Huds. Swamps, infrequent. 
AR ACE-^ . 
Arisoema tripliyllum Torr. Woods, common. 
A. dracontium Schott. Low woods, infrequent. 
Symplocarpus foetidus Salisb. One patch known near Wadena 
on wet ground. Apparently a rare Iowa plant. 
Acorus calamus L. Swamps, frequent. 
LEMNACE^. 
Spirodela polyrrhiza Schleid. Ponds, abundant. 
Lemna trisulca L. Ponds, infrequent. 
L. minor L. Ponds, common. 
ALISMACE^. 
Alisma plantago L. Ponds, common. 
Sagittaria heteropJiylla Pursh. Wet ground or in water, 
common and very variable. Mr. Cratty writes of the speci- 
mens sent him, ‘‘What a maze of forms.” 
8. variabilis Engelm. Wet ground or in water, probably 
infrequent. For the sake of uniformity I have followed Gray 
in synonomy here instead of Mr, Cratty’s paper. Bull. Lab. of 
Nat. Hist., State University of Iowa 3: 136, F. 1896, though 
the latter doubtless offers many improvements. The same is 
true of all the aquatic plants. 
