148 



Mycologia 



rust than is presented by the aecia of Puccinia Acnisti Arth., 

 f ound on the same host about in the same region. The habit also 

 differs from A. solanitum Speg., which appears like a systemic 

 form. 



112. Aecidium abscedens Arth. (on Rubiaceae) 

 Randia aculeata L., San Jose, Dec. 15, 191 5, 258. 



This apparently heteroecious species has heretofore only been 

 known from Porto Rico (Mycol. 7 : 315. 1915). 



113. Aecidium ampliatum Jackson & Holway sp. nov. (on 

 Carduaceae) 



Eupatorium sp., El Alto near Cartago, Jan. 16, 1916, 434. 



Pycnia epiphyllous, gregarious, conspicuous, yellowish becom- 

 ing orange, subepidermal, globoid or flask-shaped, 80-1 00 /x 

 broad ; ostiolar filaments short. 



Aecia hypophyllous, crowded on yellowish spots 2-8 mm. across, 

 opposite the pycnia, cupulate ; peridium strongly recurved, lace- 

 rate; peridial cells rhomboidal, 21-23 by 42-45^, considerably 

 overlapping, the outer wall 2.5-3//, thick, smooth, the inner wall 

 3.5-4.5^ thick, prominently rugose-verrucose ; aeciospores glo- 

 boid or broadly ellipsoid; 23-27 by 27-30^; wall colorless, thin, 

 1 fi, very finely and closely verrucose. 



It can not be predicted whether this form is the aecium of an 

 autoecious or heteroecious species. 



114. Uredo Arundinellae Arthur & Holway sp. nov. (on Poaceae) 



Arundinella Deppeana Nees, San Ramon, Jan. 14, 1916, 431. 



Uredinia hypophyllous, scattered, oval or oblong, minute, 0.1- 

 0.3 mm. long, early naked, pulverulent, cinnamon-brown, rup- 

 tured epidermis evident; urediniospores broadly ellipsoid, globoid 

 or obovoid, 26-29 by 27-37 Pi wa -U cinnamon-brown, thin, 1-1.5 /x, 

 moderately echinulate, the pores usually 3, sometimes 2 or 4, equa- 

 torial. 



Morphologically the species is similar to P. Arundinariae , but 

 the urediniospores are somewhat larger, and with a much thinner 

 wall. The pores are also more variable in number. As the 

 hosts are only distantly related it is quite certain that the two 

 rusts are only superficially associated. 



