3SS University of California Publications in Botany [Vol.8 



Gen. So. African Plants, 1838, p. 393. Phaeophyceae Kjellman, in 

 Engler and Prantl, Die natiirl. Pflanzenfam., Teil 1, Abt. 2 (Lief. 60), 

 1891, p. 176. 



The Melanophyceae, or Brown Algae, are, with very few exceptions, 

 marine and are, properly, all multicellular. We feel convinced that 

 the termination -phyceae should be retained for the subclasses of the 

 class Algae, or Phycophyta. Since Stizenberger's Melanophyceae, 

 1860, applies to the same group of plants as does Kjellman 's Phaeo- 

 phyceae, 1891, and since Stizenberger's term seems equally applicable, 

 we have chosen it in preference to Kjellman 's, even though Phaeo- 

 phyceae is at present in general use. The Melanophyceae are much 

 more complex in both structure and reproductive processes than are 

 the Chlorophyceae or the Myxophyceae. In size, they range from 

 minute disks to plants of considerable size, reaching among the kelps 

 to a length of possibly 100 meters or longer. It has seemed the more 

 natural to restrict the Melanophyceae to the multicellular forms than 

 to include the unicellular forms with chlorophyll and a brown pigment. 

 The Bacillariales, or Diatoms, and the Peridi.niales, as well as certain 

 groups of the Flagellates, even if they may be regarded as belonging 

 to the vegetable kingdom, seem to have no characters that would 

 associate them with the Melanophyceae except the possession of a 

 similar brown pigment. 



The Melanophyceae are, with few exceptions, viz., Phacosaccion 

 Farlow and Omphalophylhon Rosenvinge, provided with specialized 

 zoosporangia or with gametangia or with both. In one order, viz., 

 Dictyotales, the non-sexual spores are always motionless. 



There is an antithetic alternation of generations in most of the 

 groups of the Melanophyceae, the Fucales being the only order in 

 which it is certainly absent, where the sporophyte generation of this 

 order is considered as represented by the products of the division of 

 the oogonial cell. In the Sphacelariales and the Ectocarpales it is not 

 so clearly proved as yet, but Kylin (1918) has demonstrated reduction 

 divisions of the primary nucleus of the zoosporangium in certain 

 species. The two generations in both of these orders are alike in size. 

 We find species, however, in which the gametophyte is microscopic, in 

 striking contrast to the large, often even gigantic, sporophyte. The 

 same relation between gametophyte and sporophyte is suspected, but 

 not yet observed, in the Desmarestiales, Chordariales, and Dictyosi- 

 phonales. In the Cutleriales the two generations may be similar or 

 dissimilar, while in the Dictyotales they are similar in size and 

 vegetative structure. 



