388 Transaeiions of the Society. 



relationship will doubtless exist between these protospores and tlie 

 capitules in Bavenelia. 



Hitherto the bodies which we have termed capitules in this 

 genus have been spoken and written about as spores. Berkeley calls 

 them pseudospores, and his intention is probably to foreshadow the 

 idea that the true spores are produced on germinating threads 

 which proceed from them as demonstrated in Puccinia. His obser- 

 vations on another occasion* lead to this inference, when he 

 says " The spore in this case is of considerable size, and evidently 

 reticulated, and below it, either free or in contact with the stem, is 

 a circle of colourless bags foreshadowing a more complicated system 

 of articulation than even in the Pucciniei. The germination of 

 these has not at present been observed. It is probable that the 

 number of threads to which the spores give rise is considerable." 



It was during the examination of the capitules oiB. aculeifera 

 that we first became satisfied as to the structure of these bodies. 

 The convex, almost hemispherical capitules, or complex spores, are 

 about one-tenth of a milhmetre in diameter, composed, as we have 

 demonstrated, of cells, about seven in each direction closely packed 

 and agglutinated together side by side. By means of a gentle 

 pressure exerted upon the mature capitule we forced these cells 

 apart, and found them to be club-shaped, nearly • 07 mm. long, '016 

 mm. broad at the apex, and • 01 mm. or less at the base (Fig. 12) ; 

 the upper portion coloured deep sienna brown, the base uncoloured, 

 the colour diminishing from above downwards. These cells, which 

 remind one so strongly of the spores in Melampsora, are un- 

 doubtedly the individual spores (or pseudospores) which together 

 combined into a hemispherical mass form the complex spore or 

 capitule of Bavenelia. These clavate pseudospores converge at 

 their bases towards the stem or central point by which the capitule 

 is attached (Fig. 13). The " reticulations of the spore " as apphed 

 to the capitule indicate the lines of union into one common capi- 

 tulum. Comparing it with a familiar object, one of these capitules 

 may be said to resemble the fruiting capitulum of the " sunflower " 

 in which the seeds represent the pseudospores and the reflexed 

 limbs of the involucre the sterile cysts. 



Having thus observed in one species the ready separation of the 

 component pseudospores, it became advisable to ascertain how far 

 this facility existed in the other species ; and we are convinced that 

 the structure is the same in all, that the cells are complete in them- 

 selves each with its own proper cell-wall, that they are only 

 temporarily attached to each other, and on arriving at maturity, 

 sooner or later, the capitules resolve themselves into the individual 

 pseudospores. Only in B. Indica have we yet seen them so propor- 

 tionately long as in B. aculeifera ; in some the cells do not much 

 * ' Introduction to Cryjjtogamic Botany,' pp. 32'1. 



