CONTRIBUTIONS TO THE FLORA OF IOWA. 73 



Polygonum tenue, Michx. (No. 683'^), has a number of times been 

 reported with specimens from various parts of the State, but has always 

 heretofore proved to be a small form of the abundant P. ramflsissimum. 

 The true P. tefiue is, without doubt, a rare plant in Iowa. The region 

 from which the i)resent specimens come, the extreme northwestern 

 corner, is geologically and botanically very unlike the rest of the State. 



Potamoi^don pusillus, L. (No. 783 '^j, is said by Mr. Morong to be 

 the typical form, but what has generally been called var. vulgaris. 



Schedomuxrdus TexaJius, Steud. (No. 950'') is described in Gray's 

 Manual under the name of Lepiurus pa?iiculatus, Nutt. See North 

 American Genera of Grasses, by F. L. Scribner, in Bull. Torr. CI., IX., 

 134, and X., 8; also. Grasses of United States, by George Vasey, 

 1883, p. 32. 



Agropyrum vifllaceuin, Vasey (No. 952^^;, is described in Gray's Man- 

 ual vmder the name of Triticum violaceum, Horn. See Vasey's Grasses 

 of the United States, 1883, p. 45. 



Isoetes mela7iopoda. J. Gay (No. 980), was collected near CImton by 

 Dr. George Vasey in 1862, and specimens are now in his herbarium in 

 IlHnois. They were determined by Dr. Engelmann. No other speci- 

 mens are known to have been collected in the State. The plants, 

 being grass-like in appearance, are doubtless overlooked. The Iowa 

 specimen is cited in Engelmann's Isoetes of North America, p. 3. 



Marsilia vestita, Hook. & Grev. (No. 983), is given solely on the au- 

 thority of Wood's Class-book of Botany (editions of i860 and 1869), 

 p. 810, which says that it was "sent from Iowa, near the Mississippi 

 River, by Dr. Cousens." Probably no other specin\ens than those re- 

 ferred to have been collected in the State. The citation of Iowa under 

 M. vestita in Underwood's Our Native Ferns and their Allies, p. 115, 

 is on the same authority, as I am informed by the author. In Wood's 

 Botanist and Florist (1870), p. 360, a later publication than the Class- 

 book, we find that Iowa is credited with M. uncinata, Br., with no ref- 

 erence to M. vestita of the Class-book, or to Dr. Cousens' specimens. 

 Inquiry at the College of Pharmacy, in New York City, where Prof. 

 Wood's herbarium is now deposited, discloses the unfortunate fact that 

 many of the specimens were considered worthless, when the herbarium 

 recently came to be mounted, and were destroyed, and that as the 

 specimens in question cannot be found, they were doubtless among the 

 discarded ones. We have therefore no direct way of determining with 



