Knupp, N, D. — The Flowers of Myriophyllum spicatum L. — Proceedings of 

 the Iowa Academy of Sciences, vol. XVIII, 1911, pp. 61-73, 



Wylie, R. B. — Notes on Heteranthera dubia. — Ibid., vol. XIX, 1912, pp. 

 131-132. 



Fare, C. H. — ^The Diclinous Flowers of Iva xanthiifolia Nutt. Ibid., vol. 

 XX, 1913, pp. 151-160. 



"Wylie, R. B. — A Long-stalked Elodea Flower. — Bulletins from the Labor- 

 atories of Natural History, State University of Iowa, vol. VI, 1913, 

 pp. 43-50. 



GiDDiNGS, L. A. — Transpiration of Silphium laciniatum L. — Plant World, 



vol. 17, 1914, pp. 309-328. 

 Boot, David H. — 



69 



