12 Witson: NortH AMERICAN PERONOSPORALES 
thick, the lower smaller, hyaline, globose or ovoid, 18-25 x 18— 
23 #, membrane about I-24 thick ; odspores produced in the leaves 
and stems of the host, 50-65 y, light-brown, finely and densely 
papillate or echinulate, the tubercles showing a tendency to be 
confluent and form short ridges. 
Infesting as it does only the maritime Caryophyllaceae, this 
species is of necessity restricted in its habitat, yet appears to 
be as widely distributed as its chief host, Tissa marina, from 
which it was originally described. Material has been exam- 
ined from various European countries and from Algiers. Hen- 
nings * also reports it from South America. What is presumably 
the same species is described as Cystopus argentinus by Spegazzini, 
who fails to give really distinguishing characters by which it can 
be separated from the present species. The morphology of the 
species has been studied by Ruhland.t+ 
On CARYOPHYLLACEAE : 
Tissa leucantha (Robs.) Greene, California, Parish 4462. 
Tissa marina (L.) Britton, California, Parish; New York, 
Britton. 
Type tocatity: Germany, on Arenaria marina L. = Tissa 
marina (L.) Britton. 
Distrisution: New York and California. Also in South 
America, Europe and Africa. 
6. Albugo Swertiae (Berl. & Kom.) 
Cystopus Convolvulacearum Speg. var. Swertiae Berl. & Kom.; 
Berl. Riv. Pat. Veg. g: 26. 1900. dees 
The only known locality for this species is the Amur region in 
eastern Siberia where it was collected on Swertia connata Schrenk 
by Komarof. An examination of this material shows the present 
species to be very closely related to A. Tragopogonis, yet quite dis- 
tinct. Species of Swertia and the closely related genus Frasera 
have a wide distribution in North America. 
7. Arsuco Tracopoconis (DC.) S. F. Gray, Nat. 
Arr. Brit. Pl. 1: 540. 1821 
Uredo candida 8 Tragopogi Pers. Syn. Meth. Fung. 233. 1801: 
Uredo Tragopogt DC. Fl. France 2: 237. 1805. 
* Hedwigia 35: 210. 1896. 
+ Hedwigia 41: 179. 1902. 
