VALONIACE^. n 



the outer of which are hyaline and homogeneous, the innermost traversed by parallel, 

 longitudinal, anastomosing veinlets. Spores seriated in moniliform strings, and 

 developed from the veinlets of the inner cell-wall (!) 



The highly curious little Alga on which the present genus is founded so closely 

 resembles a Cladophora that it will readily pass for one, unless it be very closely examined 

 under a powerful microscope. Indeed so great is the resemblance to a branched 

 Conferva that I formerly distributed it to my friends with the manuscript name of 

 Cladophora ccespitosa, under which it Avas my intention to have described it in the 

 present work ; nor did I discover my error until I commenced making sketches for 

 the plate now given. I was then first struck by the peculiar opacity of the dissepiments ; 

 and afterwards by what looked like a compound cellular structure in the walls of the 

 cells. On applying a higher power, other characters came out which induced me to 

 dissect one of the articulations, when I discovered the curious structure of the inner 

 membrane or primordial utricle ; in which (as far as I can make out) the spores are 

 developed. To see the structure, as above described, the readiest mode is to proceed 

 as follows. Cut off a portion of one of the long cells which terminate the branches ; 

 place it on the table of a dissecting microscope, moisten it, and you may readily express 

 the viscid endochrome, which generally contains, besides the usual starch and chloro- 

 phyll grains, a number of pyramidal crystals ; but these are probably adventitious. 

 When the endochrome has been pressed out, the structure of the inner membrane of 

 the cell-wall may be partially seen ; but to see it clearly, the outer coats must be 

 removed. This may readily be done, either by tearing, with a pair of dissecting 

 needles, or by making a longitudinal section through the cell, when the different coats 

 easily separate, on the section being teased in a drop of water. The outer coat, or 

 coats (for there are tivo or more, though the secondary ones sometimes elude detec- 

 tion, owing to their extreme tenuity) are quite transparent and structureless, as is 

 usually the case in the walls of cellular tissue. But the inner coat offers a peculiarity 

 of structure which I have not noticed in any other Algae, nor have heard of its occur- 

 rence in the cells of any other plant. At first sight the membrane seems to be 

 composed of numerous minute, elongated fusiform cellules, not unlike the wood-cells 

 of phanerogamous plants, but totally unlike any algae-cells known to me. Careful 

 examination has however convinced me that the appearance of cellular structure is 

 deceptive ; and that the membrane itself is homogenous, but traversed by slender 

 filaments or nerves, which anastomose together, forming areolae which look like cells. 

 These filaments give oS free ramuli whose apices swell into spores ; and (probably) by 

 repeated cell division produce the strings of roundish spores, which are so conspicuous 

 in most of the areola;. The appearance of the whole membrane with its spores is as 

 if a number of the ascl of a lichen were placed side by side ; the true structure, 

 however, I need hardly say, is widely different. 



The generic name is bestowed as a grateful tribute to the memory of the late 

 Dr. Blodgett of Key "West, who had zealously collected and studied the Algte of the 

 reefs where this plant grows, and to whom I am indebted for many specimens of the 

 rarest Algaj of the Florida Keys. 



