EELATIOX BETAVEEN OONIDIA AKD HYPII.T: IN LICHENS 178 



club-shaped expansions Avith gonidia at the end. The club-shaped 

 bi-anches are otten met with. They are sometimes in groups, but are 

 always short. If this structure be examined without staining the 

 gonidial cell-walls, one is led to imagine that the swollen part of the 

 hypha has budded oif an algal cell. Such an impression is confirmed 

 by tlie observation that the hyphal swellings just described have a 

 somewhat thin envelope and the protoplasmic contents show a feeble 

 turquoise-green colour to the light. The suggestion that the gonidia 

 are budded off from the hyphae is increased where a few rounded 

 hyphal swellings are next in order to the end of the club-shaped 

 expansion adhering to the algal cell. In this case a superficial obser- 

 vation may unconsciously put the consecutive swellings not merely 

 into connection with one another, but will include in this consecutive 

 series the gonidium at the end of the chain, the more so, perhaps, 

 because of the close connection with the hyphal branches, for even 

 the most minute examination fails to show the line of union without 

 the aid of reagents. This chain-like appearance can easily be observed 

 both in those gonidia attached to a hypha and to those beaded in a 

 row should they be close to a h^'pha. In such cases as I observed, 

 the nearest gonidium was the least coloured with chlorophyll and the 

 gonidium at the end of the row the most highly coloured. I shall 

 not go so far as to assert that Elfving came to his conclusions on the 

 basis of the above connection of the hj-phse and gonidia in the lichen 

 thallus, as no drawings accompanied his paper; but in any case the 

 microscopical drawing I have described might well serve to illus- 

 trate it. 



The misinterpretation respecting the hyphal origin of the algal 

 cells must finally be abandoned if reagents are applied to the speci- 

 men, for the staining reaction will be only apparent in the gonidial 

 envelopes, leaving the hyphal cell-walls unchanged. Personally I 

 always prefer ClZnI. On the application of this reagent the gonidial 

 envelope became violet and the limits of the gonidial and hyphal 

 junction were sharply defined. 



There can be no doubt that the hyphal club-shaped swellings 

 attach themselves to the envelope of the gonidia. In the first place 

 the attachment takes place, apparently, only on a small part of the 

 gonidial envelope in comparison with the later development. The 

 club-shaped swelling, as it continues to grow, then increases the area 

 of contact, spreading its broad base over the envelope of the gonidium. 

 This may easily remain unnoticed, making it necessary after the use 

 of ClZnl for the gonidia to be viewed in different planes. Besides, 

 this, the club-shaped swellings may give rise to buds as full of proto- 

 plasm as the swellings themselves. The secondary buds mav be 

 obscured by the neighbouring gonidia, thus forming, out of the gonidia 

 and the thick hyphal distention filled with protoplasm, even more 

 shapeless masses than the network of gonidia and short hyphal cells 

 described above. 



Compared with the protoplasm of the gonidia, the protoplasm of 

 tha hyphal distentions is less easily stained : it takes the stain only 

 after a comparatively lengthy inmiersion in the staining tluid ami 

 loses it more readily when washed. Taking into consideration the 



