the genus Calostoma , Desv. 
35 
upwards, remaining in contact with the brown layer at the 
tips of the rays. A young unexpanded Geaster is more or 
less globose and furnished at the apex with a prominence or 
umbo, as in Calostoma . A vertical section at this stage shows 
the external brown layer to be continuous over the apex, 
whereas the umbonate portion of the collenchyma-layer is 
fluted, as in the endoperidium of Calostoma. 
The fluted appearance of the umbo in Geaster is due to 
what might be described as puckering, extending through the 
entire thickness of the substance, the external ridges producing 
corresponding internal furrows. At this period the umbo and 
upper portion of the inner peridium are differentiated from, 
but in intimate contact with, the inside of the collenchyma- 
layer, and are as it were modelled into form during the 
differentiation of the latter, the external configuration of the 
mouth and depressed area circumscribing it, resulting, as in 
Calostoma , from external pressure. In Geaster the inner 
peridium is confluent at the base with the collenchyma-layer, 
in some species sessile, in others elevated on an elongated 
stem. This feature constitutes the most pronounced structural 
difference between the present genus and Calostoma. Points 
of minor importance are the presence of a more or less 
prominent columella and capillitium in Geaster. 
Professor de Bary, in pointing out the connection between 
the Phalloideae and the rest of the Gastromycetes , says : ■ The 
connection between Clathrus and Geaster appears to me to be 
still more completely established by the genus Mitremyces , 
which is chiefly American and still far from being thoroughly 
known. But I do not attempt to describe it here, for I have 
no sufficient account before me of the history of its de- 
velopment V 
This idea, which suggested the present attempt to trace the 
affinities of the genus under consideration, is in the main 
correct, although the intermediate forms necessary to prove 
true relationship between Calostoma and Phalloideae are not at 
1 Fungi, Mycetozoa and Bacteria, Engl. ed. p. 326 . 
D 2 
