♦ 



MONOGRAPH OF THE LABOULBENIACE^i. 



307 



simple branches, arising side by side antcro-postcriorly ; the middle cell usually bears a single 

 similar sterile branch arising from a small cell cut off from its upper inner angle, and also some- 

 times producing an antheridial branchlet ; the basal cell has two cells similarly cut off from its 

 distal end on either side, each producing antheridial brauchlets. Spores, 50 X 4 fx. Perithecia, 

 125-140 x 30 fi ; the stalk-cell, 75-170 p. Main appendage, 110-185x18^; its longest 

 branches, 750 /x. 



On Lathrobium nitidulum Lee, and L. punctulatum Lee, Cambridge, Mass., and Kittery 

 Point, Maine. 



This striking form does not appear to vary to any great extent even on the two hosts above 

 mentioned, and well developed specimens correspond closely to the type figured on Plate IX (fig. 

 12). The long, brown, rigid branches of its appendages arc perhaps the most striking apparent 

 difference which distinguishes it from R. pallidus ; but although with only the type of It. palli- 

 das before him (figs. 7-8), one would hardly hesitate in separating the two species, the European 

 material and some of the varietal forms of this species render it not altogether certain that 

 the present form is distinct. The fact, however, that R. pallidus occurs on the same host (L. 

 punctulatum) in the same position and in its typical form, and that no tendency to variation 

 toward R. pallidus is visible in the abundant material of R. cristatus, derived from several speci- 

 mens of this host on which it was found at Kittery, indicates that at least these differences are 

 not variations due to the position of growth or the character of the host. 



The hosts affected were collected in considerable numbers about wet bogs or beside ponds ; 

 but the species seem very rare. 



RHIZOMYCES nov. gen. Plates III-IV. 



Receptacle consisting of two cells, the lower with rhizoid-like outgrowths from its base which 

 penetrate the body cavity of the host. Perithecia solitary, borne on a stalk-cell arising from 

 the sub-basal cell. Antheridial appendages consisting of numerous superposed cells all of 

 which, except the lowest, produce externally antheridial branches, their basal cells bearing simple 

 antheridia of the usual flask-shaped type. 



This genus is clearly distinguished from all others by the structure of its strikingly peculiar 

 appendage. The antheridia, however, are exactly like those of Laboulbenia, although the 

 appendage in other respects differs fundamentally from that which is found in the genus just 

 mentioned. It seems only remotely allied to any of the known genera, and is unique in that it 

 produces from its basal cell well developed, semi-filamentous branching rhizoids (Plate IV, fig. 

 3), which penetrate the body cavity of the host, the softer chitinous integument of which it 

 inhabits. The main axis of the appendage appears to result from successive sympodial branch- 

 ing, each cell representing the base of a sympodial branch, on which the corresponding anthe- 

 ridial branch was at first terminal. From the fact that the types are all mature individuals, the 

 early stages of development were not seen ; yet it seems improbable that they present any great 

 peculiarities, unless perhaps as i*egards the trichogyne. In the type species the position of the 

 ascogenic cells, of which there are two lying side by side in the mature perithecium, is unusual, 

 the long axis being turned at a considerable angle to that of the perithecium, instead of coincid- 



