12 



BULLETIN. 1037, U. S. DEPAETMEISTT OF AGRICULTURE. 



what similar examples, the blue color of thin milk, cigarette smoke, 

 and the clear sky, wherein very fine particles are held in suspension 

 in a transparent medium. 



OTHER FUNGOUS ORGANISMS CAUSING SURFACE DISCOLORA- 

 TIONS IN GREEN TIMBER. 



In addition to the blue-stain fungi, there is another group, the 

 molds, which commonly occur upon the freshly cut surfaces of green 

 timber when stored under moist, warm, and stagnant conditions (PL 

 I, fig. 5 ; PL II, figs. 1 and 2). Molds are occasionally found growing 

 rigorously upon timber in kilns (PL I, fig. 4). This is especially 

 noticeable when the atmosphere of the kiln is exceedingly moist or 



saturated and the temperature ranges 

 from 90° to 110° F.^ or from 110° to 

 130° F. (Tiemann, 51, p. 186-187). 



Hedgcock {19) showed that the 

 blackening and browning so common 

 in the green sapwood of pine {Pinus 

 sp.), poplar {PopuJus sp.), tulip {Liri- 

 odendron sp.), red gum {Liquidatribar 

 sp.), oak {Quercus sp.), maple {Acer 

 sp.), and several other woods can 

 often be traced to species of Graph- 

 ium. He cites : 



G. ambrosiigernm n. sp., on Arizona pine 

 iPinus arizonica Eug. )• 



G. eumorpJmm Sacc, on wild red rasp- 

 berry {Riibiis strigosus) and related species. 

 G. atrovircns n. sp., on red gum (Liquid- 

 amhar stj/racijlua L. ). 

 ■ G. smaragdmum (A. and S.) Sacc, on red gum {Liquidamhar styraciflua L.). 

 G. rigidum (Pers.) Sacc, on red oak (Quercus rubra L.). 

 G. aureum n. sp., on wli te pine (Pinus strobus L.). 

 G. aJbur.i (Corda) Sacc, on beech (Fagus afropmiicca (Marsh) Sudworth). 



Graphium spp. are perhaps best known by the upright, cylindrical, 

 occasionally branched fruiting bodies 1 to 3 millimeters in height 

 (fig. 3). These are often brown to black in color and bear at the 

 tips comparatively large and, in many cases, confluent globules com- 

 posed of masses of spores embedded in a mucuslike substance. These 

 spore masses, though usually cream color, vary somewhat in hue, and 

 in some species are tinged with gray, brown, green, yellow, or red. 

 While these are the organs of fructification commonly observed, 

 other types less conspicuous and bearing the so-called secondary 

 conidia have been demonstrated in culture by Hedgcock {19). 



Pig 



bed e 



3. — Fruiting body of Graphium 

 sp. (After Miincb, 31.) 



» Information from the section of timber physics, Forest Troducts Laboratory, Madison. 

 Wis. 



