VALONIACEiE. 4r 



the outer of which arc 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 casspitosa, under which it was 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 Avhich (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 oif 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. 

 AVhen 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 hvo 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 peciiliarity 

 of structure which I have not noticed in any other Algaj, 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 alga;-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 o^ 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 areolae. The appearance of the whole membrane with its spores is as 

 if a number of the asci 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 Alga; of the 

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

 rarest Alga3 of the Florida Keys. 



