Harper—Species of Lentinus in Great Lakes Region. 375 
compacted by the persistent hyphae of the fungus. The sclerotium 
I have illustrated resembles a rhizome with definite buds from 
which the carpophores are produced. I have found the same kind 
of sclerotium produced by Polyporus radicatus and will discuss 
its nature more fully in an article on that species. Petch leaves 
the question open whether different kinds of sclerotia are confined 
to different species of fungi or whether the hyphae may assume 
different forms under different conditions in the same species. 
The Lentinus tigrinus Group 
Plants smaller, scales finer and fibrous-tufted, not spot-like, and 
spores smaller than in the Lentinus lepideus group. Usually found 
on deciduous trees. 
Pileus 1-3 inches broad, coriaceous, somewhat fleshy, thin, con¬ 
vex to plane, umbilicate, easily splitting on the margin, covered 
with fibrous-tufted, innate, brown or blackish scales on a whitish 
background. Flesh whitish, often turning reddish when bruised. 
Lamellae narrow, very crowded, decurrent, finely serrate or erose 
on the edges. Stipe 1-3 inches long, 1-5 lines thick, solid, flexuous 
or curved, whitish, more or less scaly like the pileus. Spokes ob¬ 
long, obliquely apiculate 3-4 x 6—9/x. Basidia club shaped, 4-5 x 20- 
25/*. 
On stumps of deciduous trees. 
The large, luxuriant forms of tigrinus such as are illustrated by 
Cooke (Illust. 1138), and Rolland (Atlas 45), are not found in our 
region. The reason may be that the carpophores are so universally 
parasitized that they have become stunted. There is much variety 
in the group and I show four well marked forms in the photographs. 
1. Plate XVIII. Rather small plants with the pileus thin and 
easily splitting on the margin. White with small dark scales on the 
pileus and stem. Stem short, equal, slender, flexuous or curved. 
This is the form shown in Cooke’s Handbook, Volume 1, figure 56, 
and copied by Winter in Kryptogamen Flora 1: 488. It appears 
to be the usual form in Europe, though the form shown in Plate 
XIX is more common with us. The gills of the plant in figure E 
are partially parasitized. 
2. Plate XIX. Small plants with regular orbicular pileus which 
is thick and incurved, not splitting on the margin. It resembles 
somewhat L. dunalii as illustrated by Cooke (Illust. 1139 B), which 
