A STUDY OF DEVELOPMENT IN THE GENUS CORTINARIUS 32 1 
CORTINARIUS ANFRACTUS 
(Figs. 1-18) 
Primordium of the Basidiocarp. — The earliest stage obtained of 
C. anfr actus was a tiny button \ mm. in length and somewhat conical 
in shape. But for its attachment to slightly larger fruit bodies, it 
might easily have been overlooked on account of its diminutiveness 
(fig. i). The tissue is homogeneous in character, being composed of 
densely interwoven hyphae, averaging 1.6 in diameter. In certain 
places on the surface, there is some evidence of a thin, deeply stained 
external layer, the protoblem. This name was proposed by Atkinson 
for the very delicate primary universal veil in Agaricus campestris^''^^, 
which separates early from the pileus in the form of very distinct and 
delicate floccose scales and never becomes concrete with the pileus, 
as does the true universal veil or blematogen. Owing to the fact that 
these buttons develop beneath the soil, and because of the friction in 
washing, it is not strange that only traces of this layer are found in 
the young stages. 
Differentiation of the Pileus and Stem Primordia. — The first in- 
ternal evidence of differentiation occurs in fruit bodies of about i mm. 
in length. In the central part of the fruit body there appears a 
deeply staining growth region, conical in form, leaving on the outside 
an area of loose ground tissue (fig. i). This conical growth area is 
the stem primordium. We may consider the outer region as a portion 
of the blematogen, homologous to that described by Atkinson 
in the species of Agaricus,'^^''^'^ Lepiota,^^ Armillaria,^'^ Coprinus,'^^ 
9 Atkinson, G. F. The development of Agaricus arvensis and A. comtulus. 
Amer. Journ. Bot. i: 3-22. pis. i, 2. 1914. 
Atkinson, G. F. Homology of the universal veil in Agaricus. Mycol. Cent. 
5: 13-20. pis. 1-3. 1 9 14. 
^1 Atkinson, G. F. The development of Agaricus arvensis and A. comtulus. 
Amer. Journ. Bot. i: 3-22. pis. i, 2. 1914. 
12 Atkinson, G. F. Morphology and development of Agaricus rodmani. Proc. 
Amer. Phil. Soc. 54: 309-343- pls- 7-i3- I9i5- 
1' Atkinson, G. F. The development of Lepiota clypeolaria. Ann. Mycol. 12: 
346-356. pis. 13-16. 1914- 
1^ Atkinson, G. F. The development of Armillaria mellea. Mycol. Cent. 4: 
113-120. pis. I, 2. 1914. 
Atkinson, G. F. Origin and development of the lamellae in Coprinus. Bot. 
Gaz. 61: 89-130. Diagrams I-VI. pis. 5-12. 1916. 
