4l8 Illinois State Lahoratory of Natural History. 



20) 4 to 6 times as long as the diameter of the perithecia; 3 to 4 times 

 dichotomously branched above, tips swollen. — Cooke and Peck, Erysiphei 

 of U. S., in Jour. Bot. 1882. 



On Gaylussacia resinosa: Ogle, Sept. 25, 6173; La Salle, 

 Sept. 30,6247. Vaccinium (vacillans?): Jersey, Oct. 14, 6318. 



This is a variable species not only in the character of the 

 mycelium, but in the length and branching of the appendages. 

 In most cases the tips are swollen, and not at all recurved. 

 There is some confusion in regard to the authority for this 

 species. Schweinitz (N. A. Fungi, p. 270) describes an Erysi- 

 phe vaccina on Vaccinium Pennsylvanicum from Berks Co., 

 Penn., while Peck (23d Rep. N. Y. State Mus., p. 65) refers spe- 

 cimens on Epigwa repens to Erysiphe vaccinii, Schw., and on 

 the same page describes Microsphcera vaccinii on Vaccinium 

 vacillans as a new species. This report was submitted for publi- 

 cation in 1870, but was not printed until three years later. 

 During this interval the species was published jointly by Cooke 

 and Peck in the Journal of Botany (Jan. 1872). As Schwei- 

 nitz's specimens were on Vaccinium, it is very probable that they 

 belonged to this species rather than to the one on Epigiea. 

 This point can probably never be satisfactorily settled, so it 

 is best to write simply M. Vaccinii, C. & P. 



M. euphorbise, B. & C. 



(Grev. IV., p. 160.) 



Amphigenous. Mycelium abundant, persistent: perithecia 

 scattered, abundant, usually small, 80-100 a^., but often larger 

 (120 ;"-), texture soft, elastic, reticulations 10-15 a*, frequently 

 obscure; appendages 15-20, very long, 5-6, or more times, the 

 diameter of the perithecium, hyaline, often slightly tinted at 

 base, irregularly flexuous and often nodularly swollen, at first 

 simple, then part of them bifid or three or four times dichoto- 

 mous, branches long, lax, tips sometimes bifid, but not swollen 

 or recurved ; asci 4-8, frequently 6, pedicellate, 35-40 by 65 ;u; 

 spores 4-6. 



Mycelium ample; appendages many times longer than the diame- 

 ter of the perithecia, once or twice forked, then lobed at the tips. — Berke- 

 ley, Grev. IV., p. 160. 



