HYMEXOGASTRACEAE 29 



specimen (Hohnel, Krypt. exs. No. 1607) by the more numerous fibrils, tawny colored 

 peridium and distinctly larger spores of the latter, which in mass and under the micro- 

 scope are decidedly more colored. 



The present plant can also be distinguished from Rliizopogon nigrescens (see below) 

 by the peridium of the latter, which is viscid when fresh and which dries a much darker 

 color, becoming inky black in most specimens, by the slender but numerous fibrils, 

 and by the pleasant but weak odor of the latter plant. A section of the peridium of the 

 present plant when put in a 7 per cent solution of KOH changes its color only slightly 

 if at all, while the peridium of nigrescens becomes a distinct orange lavender when so 

 treated. For differences between this species and R. roseolus, see that species. 



This is not at all rare with us in fall and winter, growing on bare soil or in thin 

 grass and always near or under pines or cedars; rarely found completely buried to a 

 depth of several inches. It agrees best with R. rubescens among the species described 

 by Zeller and Dodge, but has a thinner peridium in the dry state, distinctly smaller spores, 

 and a strong and pleasant fragrance. In R. rubescens the odor is said by Tulasne to 

 be weak or almost none. The variety Vittadini has spores as small (3 x 6-8yu) as in our 

 plants, but is said to have a thicker peridium when dry and not to redden so distinctly 

 when bruised. Tulasne gives the spores as 3 x 7-9^ and Hesse as 3-4 x 6-9/a. The 

 simple peridium is in section dull yellow or rosy when cut in the fresh state and sordid 

 brown or reddish brown, or blackish in areas when dry. We have examined Ravenel's 

 specimen in his Fung. Car. 1: No. 75, labelled R. rubescens Tul. with R. luteolus Vitt. 

 and R. albus Schw. given as synonyms (Herb. Dept. Agric, Washington). Our plants 

 are certainly the same, agreeing in all structural characters. The spores of the Ravenel 

 plant are elliptic, smooth, 1.8-2 x 4.4-6.2/u. Dr. Dodge has seen some of our plants 

 and thinks it best to retain them in R. rubescens for the present. The strong odor 

 and small spores is a discrepancy, and it is obvious that this group is not yet in a satis- 

 factory state. If the sterigmata are as long as stated by Zeller and Dodge, that would 

 be a further discrepancy. The plant from Hartsville (R. atlanticus) differs conspicu- 

 ously in the separable peridium which is white in section when dry, in the much smaller 

 chambers, larger spores with cupped base, and in not turning rose when rubbed. 



We have made over 20 collections of this species around Chapel Hill from 1911 to 

 date. Excellent lots of material have been collected for three successive years during 

 the fall and early winter from the same location in a pine grove near Chapel Hill. The 

 spores are very consistent in size in different collections, e.g., 2.2-2.6 x 5.5-7.4;it in No. 

 6003, 1.6-2.3 x 5.5-7.5m in No. 58. 



Collections number 7450, 7457, 7499, and 7563 differ in certain particulars from the 

 typical pleasant smelling plants such as 6003 and 7565, though two of the first men- 

 tioned collections, 7450 and 7563, came from the same location as 6003. The peridium 

 in No. 7450 has a basic color of about tawny with a tint of vinaceous, in places Rood's 

 brown or burnt umber, and not rarely with black areas, whereas in No. 6003, etc., 

 the peridium has a basic color of sordid buff to clay with brown or blackened areas. 

 In the odor of the deliquescing plants the two sets of collections differ in that the former 

 plants (No. 7450, etc.) usually have an odor of decaying Irish potatoes when kept covered 

 in the laboratory for several hours while the odor of No. 6003 is very pleasant. In the 

 texture of the dried plants the two sets of collections show some differences. Numbers 

 7450, etc., are all hard and brittle when dry while many of the plants in No. 6003, etc., 



