64 Witson: NortH AMERICAN PERONOSPORALES 
Odspore with numerous small tubercles; conidial 
membrane with an equatorial thickening. 4. A, [pomoecae-panduranae, 
Odspore finely echinulate; conidia dissimilar, the 
terminal larger. 5. A. Lepigoni, 
OSspore reticulate (unknown in nos. 8 and 9); conidia cylindric or elliptic, usually 
longer than broad, if discoid the membrane with an equatorial thickening. 
Odspore with the areolae unoccupied ; conidial membrane with an equatorial 
thickening. 
Oéspore coarsely reticulate ; conidia elongate. 
Oésp ith th iculations tut late at their angles; conidia cylindric 
or with more or less rounded corners, hyaline, the terminal larger. 
Conidial membrane always with an equatorial thickening. 
Conidia more or less rounded ; 
hosts Gentianaceae. 6. A. Swertiae. 
Conidia cylindric; hosts Com- 
positae. 7. A. Tragopogonis. 
Conidial membrane of the terminal 
conidium only with an equatorial 
thickening. . A. quadrata. 
Oéspore without tubercles; conidia obo- 
void or elliptic. 
Conidia obovoid, the terminal larger. 9. A. Ti//acae. 
Conidia elliptic, the terminal smaller. 
Conidia uniformly hyaline. 
Conidia light-yellow, the termi- 
nal with a dark equatorial 
10. A. Bliti. 
11. A. platensis. 
= 
ing pitted ; conidia discoid, yellow. 12. A. occidentalis. 
Céspore with a tubercle in each areola; conidia 
cylindric, the membrane of uniform thickness. 13. A, Portulacae. 
1. ALBuGo canp1pa (Pers.) Kuntze, Rev. Gen. Pl. 
2: 658. 1891 
Aecidium candidum Pers. in Gmelin, Syst. Nat. 27: 1473. 1791 
Uredo candida Pers. Syn. Meth. Fung. 223. 1801. 
Uredo Cheiranthi Pers. Syn. Meth. Fung. 224. 1801. 
Cystopus candidus Lév.; Berk. Jour, Hort. Soc. London 3: 271: 
1848. 
clavate, about 3 . 
_ with uniform thin walls, 15-18 #; odspores usually confined to the 
_ Stems and fruits of the host, rarely in the leaves, chocolate-colored, 
