PITHOPHORACEuE. 147 



The reproduction of individuals may, however, be effected also in another 

 way than by the formation of spores. Besides the specimens which 

 form spores, there are others which never do so. These, which are dis- 

 tinguished by a richer ramification, transform part of their cells into so- 

 called " prolific cells." A common vegetative cell grows richer in 

 chlorophyll coloured protoplasm and starch, and is thus made fit to form 

 a new individual. This the prolific cells do, when they have been made 

 free, by the destruction of the mother specimen, by forming a new speci- 

 men laterally near their top, in the same manner as a branch and later 

 a system of branches is formed by a cell in the fertile specimens. That 

 the specimens originated by prolific cells have the power of forming 

 spores is certain, as well as that specimens forming prolific cells may 

 have been originated by spores. I do not know with certainty whether 

 specimens forming prolific cells may have been originated by prolific 

 cells themselves, but it seems to me in no wise improbable. Witt- 

 rock, 1. c. 



Pithophora Kewensis. Wittr. Hon. p. 52. 



Principal filament of the cauloid part of the thallus, in fertile 

 specimens, on an average '059 m. thick, with solitary branches 

 of only one degree (rarely of two), spores single, partly enclosed, 

 partly terminal, the enclosed spores cask-shaped, but more 

 elongated, on an average '08 m. thick and '2 m. long, the 

 terminal spores cask-shaped, with the upper end conical and the 

 top somewhat rounded, on an average '088 mm. thick and '219 

 mm. long ; the rhizoid part of the thallus as a rule unicellular. 



Wittr. Mon. Pithoph.'t. 1 f. 8, t. 2 f. 1-12; t. 3 f. 1-9; 

 t. 4f. 2-11; t. 5 f. 9 10. 



In tank, Water-lily house, Kew Gardens. August. 



This singular plant is thought by Wittrock to have been an importa- 

 tion from Brazil. It has not been seen in its original locality for two or 

 ' three years. 



Plate LVI, Jig. 8. Portion of spore-bearing filament x 20. Fig. 9, 



portion of principal filament with spore formed at the apex of a short 



branch, and another in process of formation in the principal filament 



x 200. Fig. 10, a mature enclosed spore x 200. Fig. 1] , part of cell 



from rooting portion of a sterile thread x 200. All after Wittrock, 



