206 



MONOGRAPH OF THE LABOULBEXIACE2E. 



seen in Chitonoinyces (Plate XXVI) or Hydroeomyces, both of which genera inhabit 

 hosts that live, for the most part, submerged, and which are rapid swimmers. Under 

 these conditions of life the advantages of such a contrivance, to allow a certain free- 

 dom of motion, are sufficiently apparent. The same office of a fulcrum for the sup- 

 port of the perithecium is effected in some species of Ceratomyces by the conversion 

 of a considerable portion of the receptacle into a foot-like organ (Plate XXIV, fig. 1). 



After having become attached to the insect, and during, or sometimes before, the 

 formation of a definite foot, the spore elongates more or less distinctly and becomes 

 further divided by the formation of tranverse septa into a series of superposed cells, 

 varying in number in the different species and genera, from the further development 

 of which result the three fundamental parts of which these plants are usually com- 

 posed : namely, a main body, the receptacle ; one or more spore-producing portions, the 

 perithecia ; and lastly, one or more appendages which, in the majority of cases, are asso- 

 ciated with the formation of the male sexual organs. 



The Receptacle. The term " receptacle " has been used to designate that portion of 

 the fungus on which the appendages, togettier with the perithecia or their stalk-cells, 

 are inserted ; but it is necessarily used with some looseness, and is sometimes unavoid- 

 ably applied to series of cells which are neither homologous in origin nor similarly 

 related to the other essential organs of the plant. In the genus Laboulbenia, for 

 example, the whole body of the individual, exclusive of the appendages and perithe- 

 cium, is spoken of as the receptacle ; although, in this instance, it consists fundamen- 

 tally of the usual two superposed basal cells, while distally it is formed from a 

 consolidation of the stalk-cell of the perithecium (cell VI), which has become laterally 

 united with what is in reality the base of an appendage (cells III-V). In other cases 

 it is often difficult to determine exactly how the receptacle should be limited, as, 

 for example, in the genus Chaetomyces (Plate XI, fig. 20), in which it consists 

 of a single series of superposed cells which give rise directly to perithecia or to 

 appendages. 



The simplest type of receptacle, which is found in more than half of the genera, 

 consists of only two superposed cells, the upper of which bears the appendage, at first 

 terminally; while the perithecium, or perithecia, if there are several, are lateral pro- 

 ductions from the same cell. This type is well illustrated by such genera as Haplo- 

 myces and its allies (Plate VII) Compsomyces (Plate XI, fig. 7) and similar instances; 

 while, as has been above indicated, even genera like Laboulbenia are fundamentally 

 similar. In other genera various degrees of complication ape found in the develop- 

 ment of the receptacle which passes gradually from the simple two-celled type to 



