20 



Mycologia 



On Cephalanthus occidentalis L. Victoria, 2539 (type) ; 

 Austin, 2869. 



When this disease is present the entire foliage of the tree is 

 seriously affected. Isolated spots are about 1 cm. in diameter, 

 and reddish-brown with a darker border. The spots often have 

 narrow rings of this darker brown tissue, rendering them zonate. 

 Most commonly these spots are irregular in outline, as the 

 diseased areas have fused, causing a large part of the leaf to 

 become dry. The lower surface of the spots is much more 

 dilutely colored ; on the upper surface, the profusion of conidio- 

 phores and conidia render the spots grayish. Where the disease 

 has been observed the trees are almost entirely deprived of their 

 leaves. 



Cercospora Prosopidis 



Maculis irregularibus, angularibus, brunneis, margine angusto 

 atro-brunneo limitatis, initio saepe folii margine insidientibus 

 demum totum f olium occupantibus necantibusque ; conidiophoris 

 amphigenis, dense aggregatis, aequaliter brunneis, continuis, 

 18-30 X 3-4 ^5 conidiis rectis, brunneolis, cylindraceis v. leniter 

 clavatis, i-pluriseptatis, 20-70 X 4-5 



On Prosopis glandulosa Torr. Uvalde, 1959 (type) ; Luling, 

 2264; Gonzales, 2663; Falfurrias, 2468; Kennedy, 2824; Flores- 

 ville, 284/. 



This disease is characterized by the presence of irregular, 

 angular, brown patches which occupy one side of the midrib of 

 the leaflets or extend across the whole leaflet, and are generally 

 bounded by a narrow brown border. The spots may be either 

 terminal or removed from the apex of the leaflet, and frequently 

 advance until the whole leaflet is killed or drops from the tree. 

 In some cases it is very abundant and causes considerable defolia- 

 tion. Its greatest development may be found in dense mesquite 

 thickets. 



Cercospora xanthicola 



Maculis numerosis, interdum 400-600 in quoque folio .5-2 mm. 

 lat. (plerumque 1 mm.), centro cini-griseolis vel brunneolis, mar- 

 gine atro-fusco angusto limitatis ; conidiophoris amphigenis, 3-8- 

 fasciculatis, apice hyalinis, nodulosis, continuis, raro septatis, 60- 

 100 X 3-3-5 conidiis tenuisimis, clavatis, gradatim attenuatis, 

 apice obscure septatis, subhyalinis, 105-135X3^ saepe 245 

 longis. 



