84 MB. J. B. CAEBUTHEES OF THE CYSTOCAEPS OP 



and in the ripe fruit as well the spores are nearly always of the 

 same maturity. 



These fertile cavities are distributed in fairly large numbers 

 over the whole space of the fruit-nucleus ; the individual spaces 

 are separated by more or less thick layers of the interwoven 

 filaments. Dispersed between these spaces many of the old me- 

 dullary cells can be seen, generally compressed, but still relatively 

 very large ; and it is specially clear that these old medullary 

 cells have no connexion with the formation of the nucleus. 



In each fruit-nucleus many of the fertile cavities are quite on 

 the border of the filamentous network, and touching the inner- 

 most cells of the cortex. These cells, as before mentioned, are 

 surrounded by small interstitial cells and filamentous rhizoids, 

 and so form what may be termed an involucral layer ; but this 

 layer is so little characteristic here in Callopliyllis obtusifolia, 

 that it is better not to speak of it as a separate layer *. 



About the same time as the spore-clusters are beginning to 

 develop, a further thickening of the cortex on both sides of the 

 fruit commences. At one side of the fruit, at the place where 

 the procarp originally was, the cells of the wall part assunder, 

 and there arises a cylindrical canal through the whole thickness 



of the wall. 



t 



dense masses of hair-like cells at right angles to the pore, and 

 nearly filling the whole of the canal. The pore is often formed 

 very early, before the formation of the spore-glomerules and 

 before the spore-clusters have developed in size and have become 

 fully matured spores. Such cell-clusters gradually develop into 

 spores, the single cells become larger and more intensely coloured ; 



* If such an involucral layer in other species of Callcphyllis is distinct 

 enough to be considered as a peculiar layer I cannot say. J. Agardh expressly 

 mentions, in his 'Epicrisis Floridearum/ p. 228, in the description of the genus 

 Callopliyllis such a layer ( <r nucleum .... plexus peculiar! ambit u definitum , '); 

 and also in his ' Morphologia Floridearum/ pp. 205 and 206, for Callopliyllis a 

 " stratum circum nucleare " round the fruit-nucleus is noticed. He attributes 

 to this layer an important part in the development of the fruit. So far as the 

 species of Callophy/lls which I have studied is concerned, this layer is so indis- 

 tinctly defined, that it is not easy to clearly distinguish it ; and it is certainly 

 quite without peculiar function in the development of the cystocarp. 



t In some cases I have found that in the middle of one fruit-wall two 

 pores were built. As the fruit was too old, I cannot decidedly say whether there 

 were two fertilized procarps near together, which developed one cystocarp. I 

 have never observed two pores at different sides of the cystocarp. 



