On the Type of a new order of Fungi. By George Massee. 175 



early period, but there is no approach to a definite separation into 

 isolated peridiola. All the free tips that clothe the sides of septa appear 

 •to become converted into basidia, which are very primitive in structure, 

 being slightly or not at all thickened at the apex, and producing usually 

 a single spore, which at first appears as an obovate terminal cell, 

 attached by a broad base. In rare instances two spores spring from 

 the apex of a clavate basidium. This type of hymenial structure agrees 

 with that of Hymenogaster decorus, as figured by Tulasne.* VVhile 

 the spores are still young and obovate, they are set free by the total 

 disappearance of the basidia, afterwards becoming spherical, and increas- 

 ing considerably in size, measuring when fully developed from 24-28 //, 

 in diameter, including the smooth colourless epispore, from 3-4 \x thick. 

 Succeeding basidia produce spores further and further from the centre 

 of the loculi, which become filled with spores, the septa consequently 

 becoming thinner, until at last nothing remains but the central portion 

 composed of parallel hypbae, separating loculi densely crowded with 

 spores, which, owing to partial gelification of the thick epispore, become 

 so agglutinated together as to remain attached for some time when a 

 section is placed in water. Contemporaneous with the above changes 

 in the gleba, the upper incurved portion of the peridium becomes erect 

 or very slightly reflexed, and the epiphragm disappears, the mature 

 plant resembling a fully developed TEcidium full of spores, but I have 

 not been able to discover in any specimen the notched margin to the 

 peridium as represented in Berkeley's figure. 



From the above description it will be seen that the leading features 

 of the plant under consideration are (1) a peridium closed above by 

 an epiphragm until all differentiation is completed ; (2) a gleba broken 

 up into numerous cavities or loculi by dissepiments or septa bearing 

 basidia on their free surfaces. The first character conclusively proves 

 the plant to belong to the Gistromycetes ; the two combined as 

 conclusively prove that, although not without affinities, it cannot be 

 placed in any hitherto defined order. The presence of a peridium 

 closed by an epiphragm indicates relationship with the IS'idularieas 

 but the gleba possesses a structure unknown in this order, whereas it 

 agrees perfectly with that of the Hymenogastreas, but in the latter 

 the peridium is indehiscent, and although of minor importance, the 

 species are subterranean. It has been suggested that the indehiscent 

 peridium in the Hymenogastreae is connected with the subterranean 

 habit, and that a species developing above ground might be expected 

 to have a dehiscent peridium. This idea may be theoretically correct. 

 It is true that subterranean species belonging to all groups are inde- 

 hiscent, but it is not equally true that allied forms growing above 

 ground are always dehiscent, as should be the case according to the 

 idea given above. Scleroderma, Polysaceum, &c, are allied, grow 

 above ground, and are indehiscent. Under the circumstances it has 

 been considered advisable to propose the genus Artocreas as the type 



* Fungi Hypogsei, tab. x. fig. ix. 2, 



o 2 



