430 Umvcrsitij of California Puhlications in Botany [Vol.7 



are identical in both. But Schizoneura comprises several species. S. 

 stihcostata, J. Ag., is mentioned first and should, perhaps, be regarded 

 as tlie type : in any case, quercifolia was declared by Agardh to be a 

 non-typical memlx'i- of the genus. I have examined part of the original 

 material of -S'. snhcostata, coll. by Schousboe. Here the costa does not 

 reach to the top of the frond, the top-cell soon loses its leading position 

 and can hardly be traced in- the older lamina, stray marginal cells 

 become centers of action, soon replaced by others ; we find conditions 

 characteristic of Nitophyllum, and the anatomical structure, with little 

 or no difference between the central lamella and the cortex, is quite 

 nitophylloid. This may also be seen from Agardh 's illustrations on 

 plate 26 in " Florid eernes morfologi" (K. Sv. Vetensk. Akad. Handl. 

 15:6, 1879) ; the figure of a growing apex is rather idealized. Of 8. 

 Davisii (Hook. fil. et Harv.) J. Ag., I have examined Hooker's type 

 (Herb. Kew). Tliis is still more like a Nitophyllum, as even in very 

 small proliferations no active top-cell is present, the growth being 

 marginal and intercalary. But in S. quercifolia the costa can be fol- 

 lowed right through to a typical, active top-cell, just as in D. sinuosa. 

 The nerves in *S'. suhcostata, Davisii, etc., are not opposite, but gener- 

 ally very irregular. There are hardly any nerves exactly correspond- 

 ing to the regular opposite ones in S. quercifolia, which must be 

 excluded from Agardh 's genus. 



In the "Nachtrag" to Schmitz' Rhodophyceae, by N. Svedelius 

 (1911), some of Agardh 's new genera were recognized and others, 

 among them Schizoneura, rejected. So if we follow Schmitz and 

 Svedelius, Delesseria comprises sangiiinea, simcosa, quercifolia, 

 hypoylossum, etc. Of course neither of those authors was satisfied 

 with this arrangement; only, as Svedelius expresses himself, as long 

 as our knowledge of the various types is so insufficient as it is now, 

 it seems better to regard some of Agardh 's genera as divisions of 

 Delesseria. Still, I think that Nienburg's studies, also quoted by 

 Svedelius, permit us to reestablish Kiitzing's genus Phycodrys, with 

 Ph. sinuosa as type. 



Tlie mode of growth in the apex of the Delesseriaceae has been 

 studied b}' various authors, including Nageli, Wille, Oltmanns. 

 Lately Nienburg made a critical examination of numerous 

 species and published his results under the title ' ' Zur Keimungs-und 

 Waehstimisgeschichte der Delesseriaeceen" (Bot. Zeitung, 66, 1908). 

 Of species of Delesseria (taken in its widest sense) he examined san- 

 guinea, sinuosa, Lyallii, alata, and hypoglossum. He distinguishes 



