Howe: Phycological studies 511 



stood and it is probable that the name has been applied to more 

 than one thing, but, in any event, it has, as a rule, a considerably 

 thicker, less gelatinous thallus than H. actinophysa, and is less 

 nitent when dry. In a cystocarpic specimen from Florida in herb. 

 Agardh, communicated by Mrs. Floretta C. Curtiss, the medullary 

 filaments are 8-13/x in diameter and have dense granular contents, 

 the subcortical layer consists of 1-3 series of ovoid or subglobose 

 densely granular cells, mostly somewhat flattened in the plane of 

 the thallus; conspicuously capitate endings for the medullary fila- 

 ments are scarcely found, though the subcortical cells anastomose 

 and are sometimes inconspicuously 3-6-radiate; it should be said, 

 however, that there are frequent large ganglioid or irregularly 

 stellate cells or filaments which have more homogeneous contents, 

 and whose branches make their way freely among the ordinary 

 vegetative filaments; these we take to be the sporogenous fila- 

 ments. But in thicker, more gelatinous plants that have been 

 referred to H. floridana, with more vacuous, more flexuous, and 

 commonly a little larger medullary filaments (such, for example, as 

 Phyc. Bor.-Am. 749a, b, and c), one often finds stellate vegetative 

 ganglia in the medulla and finds also the medullary filaments 

 terminating in the subcortex in a subglobose radiately branched 

 cell, but this rarely exceeds 30/x in diameter and its branches very 

 rarely, if ever, exceed six in number. 



Of Halymenia ulvoidea Zan. and H. coccinea Ardiss. we have 

 been able to examine no authentic specimens, but H. ulvoidea is 

 described and figured as having a dentate-ciliate margin and H. 

 coccinea, which De-Toni hints may be Callymenia Requienii, is 

 said to have a lamina only 1-2 cm. wide. 



Halymenia actinophysa is in some respects rather suggestive of 

 Aeodes nitidissima J. Ag., an apparently original cystocarpic speci- 

 men of which, collected by Berggren at Tauranga, New Zealand, 

 and sent out by J. Agardh, we have been able to examine through 

 the courtesy of Professor Farlow. But H. actinophysa is a thinner, 

 softer, more gelatinous plant (the thallus of Aeodes nitidissima is 

 about 240/i thick) and is quite different in vegetative structure. In 

 Aeodes nitidissima the medullary filaments on reaching the sub- 

 cortex send out usually 3 branches in a somewhat verticillate 

 manner, but there is very rarely any tendency to a capitate enlarge- 



