Cavers : Notes on Yorkshire Bryophytes. 



245 



young receptacle is from the first hemispherical in form, and 

 the archeg'onia are developed at an early stage. The first 

 archegonium appears on the summit of the outgrowth, towards 

 the posterior margin, then two others arise at each side, and 

 finally two more at the front. The great majority of the 

 receptacles examined showed six or seven archegonia, placed at 

 about equal distances from each other. Sometimes only five 

 were observed, and in rarer cases eight. Immediately outside 

 of the archegonia, i.e., at the margin of the receptacle, there 



Fig. 5. — A. — Vertical transverse section of a female receptacle and the adjacent portions of 

 the thallus. Two developing- sporogonia a.re shown, each enclosed in its calyptra. The 

 outer portion of the receptacle shows air-chambers with barrel-shaped pores, the inner 

 portion consists of compact starch-bearing- tissue, and the groove of the receptacle stalk 

 shows in its upper portion numerous tuberculate rhizoids, in its lower portion a number of 

 ventral scales. On the right, one of the band-like scales is shown arising frc^m the tissue 

 at the base of the stalk. X 20. B. and C. — Two horizontal sections of a female receptacle. 

 X 20. B. is from the upper portion of the receptacle, and shows the six cavities from which 

 spring tuberculate rhizoids, the latter passing- into the groove on the ventral surface ot 

 the stalk. C. is taken at a lower level, and shows six sporogonia in outline, each in its 

 involucre. 



1904 August I. 



