PLATE 19 
Helminthosporium sativum 
A. —Denuded conidiophore from 50-day old cornmeal agar culture originally isolated 
from barley leaf, showing numerous scars marking places of attachment of spores on 
branched, contorted, distal portion. X500. 
B. —Same as A, but shorter and bearing several branches. X500. 
C. —Same as A, but showing approximately 50 conidia attached in situ. Note 
the variation in size of the spores from small subglobose non-septate forms borne 
mostly on the proximal portion of the conidiophore to the larger, many septate 
ellipsoidal specimens on the distal portion. X500. 
Da-d.—Conidia produced in cornmeal agar culture, germinating in water. Typical 
germination by the production of two polar germ tubes is represented in Da, h d; 
atypical germination by the production of three germ tubes in Dc. In Db is illus¬ 
trated also marked irregularity inseptation frequent in conidia produced on artificial 
media. Xsoo- 
E.—Conidium produced on cornmeal agar showing position of hilum, thickness of 
peripheral wall, and shape characteristic of spores produced on artificial media. 
X500- 
