TWENTT-FIB8T ANNUAL MEETING. 73 



wall of oogonium thin, nearly smooth, closely fitting the oospore, June 20, 1884, 

 Manhattan; 1583, June 24, 1887, Manhattan; 1656, July 1, 1889, Manhattan; July 18, 

 1887, Mound City, Linn county; 1766, August 6, 1889, Manhattan; 466 and 467, Au- 

 gust 20, 1883, Manhattan; (Exs. Rabh. Wint. Fungi Europaei, No. 3276a, August 28, 

 1883, Manhattan); 1648, August 28, 1887, Manhattan; M. A. Carleton No. 162, Sep- 

 tember 16, 1884, Manhattan. 



This species is undoubtedly a good Plasmopara. The branching of the conidia- 

 phores is of the common pinnate type; the oospores are light-colored with a smooth 

 exospore, and the conidia, according to Trelease,* are furnished "with an apical 

 papilla, hence probably germinating by zoospores.'" 



10. Plasmopara Halstedii ( Farlow) Berl. & DeToni, in Sacc. Sylh, vol. VII, p. 242, No. 810. 

 Pekonospoea Halstedii Farlow, Notes on Some Species in the Third and Elev- 

 enth Centuries of Ellis's North American Fungi, in Proc. Am. Acad, of Arts and 

 Sci., vol. XVIII, p. 72. [Bot. Gaz., vol. VIII, p. 310.] 



Oospores and conidia on leaves of Coinjiositae Tubuliflorae May to August and 

 October; most abundant May to July. Very common. 



On Vernonia Baldwinii Torr. 

 543, June 5, 1884, Manhattan. 



On Eupatorium ageratoides L. f. 

 1793, August 1, 1889, Manhattan. 



On Silphium integrifolium Mx. 

 1591, with immature oospores, June 9, 1889, Manhattan; 1621, June 28, 1889, Man- 

 hattan; 1763, July 20, 1889, Manhattan; 525, July 23, 1886, Manhattan; (Exs. Fungi 

 Europaei No. 3279, August, 1884, Manhattan); 606, August 5, 1884, Manhattan; 1790, 

 August 11, 1889, Manhattan; 1768, with mature oospores, August 12, 1889, Manhat- 

 tan; 1788, with a few mature oospores, August 21, 1889, Manhattan; 1898, with nearly 

 mature oospores, September 26, 1889, Manhattan. 



On Ambrosia artemisiaefolia L. 



1559, June 2, 1887, Manhattan: 1604, June 14, 1889, Manhattan; 1627, June 30, 



1887, Manhattan. 



On Ambrosia psilostachya DC. 



1641, July 2, 1889, Manhattan; 1798, July 10, 1889, Manhattan; E.Bartholomew 

 No. 348, July 27, 1889, Rooks county; 1773, August .5, 1889, Manhattan. 



On Ambrosia trifida L. 

 1594, April 23, 1889, Manhattan; M. A. Carleton No. 99, May 11, 1888, Wichita, 

 Sedgwick county, 1526, May 26, 1886, Manhattan; 1570, May 28, 1887, Manhattan; 

 533, May, 1884, Manhattan; M. A. Carleton No. 996, June 1, 1888, Cloud county; 1670, 

 oospores immature, June 1, 1889, Stockdale, Riley county; 1585, June 9, 1889, Man- 

 hattan; (Exs. N. A. P. No. 1403d, June, 1884, Manhattan); M. A, Carleton No. 163, 

 June 19, 1886, Cloud county; 1662, July 5, 1884, Manhattan; 1897, September 26, 

 1889, Manhattan. 



On Helianthus annuus L. (Cultivated Sunflower). 

 1797, July 10, 1889, Manhattan. 



On Helianthus grosse-serratiis Martens. 

 1638, May 22, 1889, Manhattan; 1796, with a few mature oospores, May, 1889, St. 

 George, Pottawatomie county. 



* Preliminary List of the Par. Fungi of Wise, in Trans. Wise. Acad. Sci. Arts and Lett., vol. VI, 



1881-84. 



