284 



rally occur in llie conceplacles and are very peisislenl, I have 

 series of seclions wliere neilher myself nor olhers have been able 

 lo discover a singla one. I believe it is a small epiphylic alga; 

 on un-stained material it dillers a little in colour from the sur- 

 rounding cells, being more greenish. The shape suggests Codioliim, 

 a genus of Chloroplujceae, which, however, has a solid stipe; this is 

 the case also with the epiphylic C. petrocelidis Kuckuck. C. Nor- 

 (lenskioldianiim Kjellm. has a narrowed hollow part which tapers 

 inlo the proper slipe. I have not been able lo prove the occur- 

 rence of starch in Ihe preserved material, hut also Kjellman was 

 unsuccessful in spile of his species being a true Codiohim. 



If I am righl, why do we not find it in the old tissue? We can 

 understand that the epiphyle is unable lo penetrate the mature 

 cortex and Ihus starls by infesling the meristematic region. Most 

 of these bodies establish thems'?lves in the very young conceplacles 

 which are inilialed in the growlh-zone. They are generally found 

 in old conceplacles as well, But Iraces of Ihem must be very 

 ditficull to discover in the old sterile corlex, which is very com- 

 pact and of a dark brown colour. I have observed it in almost 

 mature cortex tissue (fig. 3 c); this is not a place for a young 

 conceptacle, but sterile corlex Ihal has nearly allained ils delinile 

 thickness. Furlher observations ought to be made on living 

 material. • 



The conceptacle. 



According to Mitchell and Whitting the initial in the concept- 

 acle of Splachnidinm is homologous with Ihe initial in the Fiicus- 

 conceptacle. Koe slates Ihal development is the same in bolh cases. 



I have made the following observations. The conceplacles arise 

 in the growlh-zone. On a small circular area the terminal cells 

 develbp inlo long, persislent hairs wilh all the cells cylindrical 

 and subhyaline, dilTering from the olher hairs. No firm cortex is 

 formed in Ihe bollom, which remains very thin (lig. 4 — 5); as the 

 surrounding tissue increases in thickness, a depression resulls. 

 According lo Roe rapid radial division of the börder cells contri- 

 bules new tissue lo the conceptacle, but Mitchell and Whitting 

 say Ihal the bordering hairs are older and Ihe central ones younger. 

 The slalemenl of Roe slands in opposition lo her own general 

 statement that the initial is the cenlre of greatest aclivity. I have 



