TA aay inc hae ban ge ain Valk paeiaci tall Pete N SR RY Meee ke ete Boy ee 
Ree Rae = J Fo EOE ys Sela Rag alone = PCIE Caste GET OLAS NS phe ice , ‘i fi : 
Oxy 3 = Sale mess ' \ f ; 
86 MISSOURI BOTANICAL GARDEN. 
These tufts of hyphae elongate into a long, round stalk, 
terminating in a bunch of either verticillate or alternate 
branches. 
PRIMARY CONIDIA. 
The primary conidia are formed on the upper portion of 
the stroma or head by an abstriction of the ends of the 
hyphae (pl. 8, f. 7). They are formed continuously, and 
as soon as mature, fall away into the mucous mass which 
; surrounds the head. The mass is hyaline at first, chang- 
ing, as it grows older, to a straw color, and finally toa 
dark brown. The stalk is usually hyaline in the first 
stages of its growth, but later becomes almost black at the 
base, shading off to a light brown near the apex, with a 
striated appearance. No chlamydospores or sclerotia are 
4 formed. At first the stroma is simple, but by the addition 
Be of branches from the base becomes gregarious (pl. 8,f. 4). 
The following are the measurements of the mycelial 
structures: the hyaline mycelium measures from 1.5 to 
2.54 in diameter, averaging 24. The colored portion 
averages in diameter about 4u. The secondary conidia 
3 measure 3.54 to 4 in length, and 1.2 to 1.5u in width, 
Po averaging 3.7¢ by 1.34. The primary conidia average 5u 
a by 3. The stalks average in length from 500p to 900u, 
: The head, including the mucous drop, measures on an 
a average 200u. These do not agree with any previous de- 
: scription of species of Graphium and the fungus is here 
named Graphium ambrostigerum, owing to the relation of 
ae the conidial stage to ambrosia beetles. 
Cultures were made on a number of kinds of wood. The 
fungus grew readily in the sapwood of pine, gum, oak and 
ash, bearing in most cases numerous heads. Secondary 
conidia are usually formed in abundance. Cultures on the 
heartwood of these trees produce little or no growth of the 
fungus. Light colored wood is stained a color varying 
from a dirty gray to a light brown, or almost black. 
