Laing. — On New Zealand Species of Ceramiaceae. 405 



ticity of the species, as I have compared it with fragments of 

 Harvey's original plants, with which it agrees well ; and my 

 own specimens were first identified by Agardh. I have, of 

 course, given a description of the plants as they are found in 

 New Zealand, and I have not adopted Agardh's or Harvey's 

 descriptions, which were drawn up from Australian and Tas- 

 manian specimens. The following measurements may assist in 

 identification : Cells of rachis 500-600 yu. long and 300-400 /* 

 broad. The ramuli are from 600-800 jx long, and contain 7 to 10 

 cells of about 60-90 //. in length, and in breadth 30-40 /x. 



5. Antithamnion plumula, Thuret (= Callithamnion plumula, 



Hook, and Harv., Fl. N.Z., ii., 258 ; J. Ag., Epicr. Florid., 

 p. 24 ; Ellis, Phil. Tr. 57, p. 426). 



Frond flaccid, rose-red, spreading and densely opposite pin- 

 nate, 5-15 cm. in height, the pinnae distichous or tetrastichous, 

 horizontal or sometimes upwardly recurved, with pectinate 

 pinnules. In luxuriant specimens the pinnules are furnished 

 with an additional row of pectinate subpinnules, and these again 

 may be pectinated. Joint-cells of the axis three or four times 

 as long as broad. The cruciately divided tetraspores in fertile 

 specimens replace the ultimate pinnules. I have seen no de- 

 scription of the cystocarps or antheridia. 



Varieties : (a) plumula, distichously pinnate, with the rachis 

 and pinnules subparallel ; (b) investiens, tetrastichously verticil- 

 late, with the pinnules flexuose and diverging, and enclosing the 

 apical portion of the stem. 



I have seen no specimens of the form plumula. Agardh, 

 however, returned some specimens collected by Mr. Crosby 

 Smith at St. Clair as A. plumula, var. investiens. This plant is 

 epiphytic and somewhat sparingly branched, and from 1-2 cm. 

 in length. The pinnules are apiculate and often retroflexed. 

 To me it appears much more like a variety of A. mucronatum 

 than of A. plumula. Agardh, speaking of the Australian form,* 

 says that it may be a distinct species, but that he is unable to 

 find any good distinctive characters. 



Distribution. — D'Urville Island (Lyall) ; var. investiens, St. 

 Clair (J. C. S.) ; Atlantic Ocean, Mediterranean, Australia, 

 Fuegia. 



6. Antithamnion flaccidum, R. M. L. (= Callithamnion flacci- 

 dum, Hook, and Harv., Fl. N.Z., ii., p. 258 ; J. Ag.. Epicr. 

 Florid., p. 20). 



Thallus flaccid, 5-10 cm. long, pinnately decompound, with 

 the larger branches and pinna? similar and lanceolate in outline, 



* Epicr. Florid., p. 25. 



