MONOGRAPH OF THE LABOULBENIACE^E. 



295 



AMORPIIOMYCES Thaxter. Plate V, figs. 17-29. 



I'roc. Am. Acad. Arts and Sci. Vol. XXVIII, p. 158. 



Sexual organs borne on separate individuals. 



Male individual. Receptacle consisting of two superposed cells, the upper bearing terminally 

 a single simple antheridium. 



Female individual. Receptacle consisting of a single cell, above which four (?) small cells 

 form the base of the solitary terminal perithecium. Spores continuous. Asci four spored. 

 Ascogenic cell solitary. Trichogyne a nearly sessile vescicle with short radiate branches. 



The above description is based on the characters of the single species A. Falagrice, since it 

 is quite certain that the second supposed species, A. floridanus, is generically distinct and not 

 even nearly related to it. The genus is among the most interesting of the whole group, not 

 only from the fact that the sexes are separated on different individuals, but from the peculiari- 

 ties of its development. It is the only form in which the perithecium is a strictly terminal 

 structure, and, unless it be Dimorphomyces, no other genus has a unicellular receptacle. 



The general development of the female is indicated by figures 20-23, the latter showing the 

 first two septa which form in the germinating spore, dividing it into three superposed cells. 

 Of these the lower, which may become partly divided, forms the unicellular receptacle; while 

 of the two others the middle one (c) constitutes the primordial cell of the perithecium proper 

 and the upper gives rise to the procarpe. 



The development of the male individual is extremely simple. As in the case of the female 

 the spore first divides (fig. 23 at the right) into three superposed cells. Of these three cells the 

 two lower remain unchanged, and may be called the receptacle ; although, from analogy with the 

 female, one might infer that the middle cell was morphologically a basal cell of the antheridium. 

 The terminal cell then elongates, producing a long tubular neck through which the antherozoids 

 formed in its basal portion make their escape (fig. 20, at the right). 



The spores are unique from the fact that even when fully mature they show no signs of septa '■> 

 and their contents are exceptional in containing a number of large oil globules (fig. 29). They 

 are always discharged in pairs, the members of which thus develop side by side. It is also an 

 invariable rule, the existence of which has been established by very numerous observations, that, 

 of the members of any such spore pair, one always produces a male and the other a female. 

 Even at the time of discharge there often is observable a slight difference in the size of the two 

 spores (fig. 29), the spore at the left in the figure being somewhat smaller than its fellow. As 

 soon as germination commences (fig. 23) the difference becomes very apparent, and the course 

 of development results which has just been indicated. When the female individual is mature, 

 if care is taken in removing it from its point of attachment, it will always be found that a male 

 individual is attached close to its base, the feet of the two individuals being adherent (fig. 17). 

 A similar juxtaposition of the sexes at the point of growth has already been noted in con- 

 nection with Dimorphomyces. 



The trichogyne bears a striking resemblance to that of the last mentioned genus, and in some 

 instances its radiating branches are furcate, as in fig. 24. The base of the trichogyne, as in the 

 case of Stigmatomyces which has been described in detail elsewhere, is formed from a small cell 



