Objects for the Microscope. 185 



CERAMIUM. 



Fourteen species are on the list of British Algae. 



The filaments are of varied colour, from red and purple 

 to white, jointed and dichotomous, which means regularly 

 and repeatedly cleft ; it has two kinds of fructification 



1. Capsules, with a membranous pericarp or outer skin, 

 containing numerous angular seeds. 



2. Oblong granules partly imbedded in the joints of the 

 filaments called favellce. 



The name is from a Greek word signifying " little 

 pitcher" which the capsules nevertheless do not resemble. 



Ceramium botrycarpum is found in fruit from August to 

 November, with clusters of favellaa on all the branches 

 most beautiful. Its chief habitat is Torquay and Bristol. 



Ceramium rubrum is common everywhere in tide-pools 

 between water-mark. 



PTILOTA PLUMOSA. 



This lovely little plant, rightly named Ptilota, frem a 

 Greek word signifying "pinnated," from its innumerable 

 small branches or pinnce, is one of our best preparations ; 

 for, even without the fruit, its cellular tissue being very 

 transparent, the cells containing the crimson endochrome 

 are distinctly seen, and render it a favourite object. The 

 stem is closely branched right and left with branchlets called 

 pinnce, and these again cut into exceedingly fine divisions 

 called pinnulce ; at the tip of the latter we find the fructi- 

 fication. This consists of two or three minute capsules 

 called favdlce, each of which contains three or four oval 

 seeds, and they are themselves surrounded and apparently 

 protected by several linear segments bending over them. 



When fresh gathered for observation, these favellce are 

 of a rich crimson with a pellucid border, and, seated in their 

 little cage of crimson pinnulse, are really beautiful. 



Another kind of fructification is found on Ptilotse, but 

 on distinct individuals ; the pinnule are broader at the tips, 

 and covered with oval bodies called tetraspores, from their 

 contain ing four seeds. 



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