Chapter VI 

 PHYLUM PHAEOPHYTA 



Phylum 2. PHAEOPHYTA Wettstein 



FucoroEAE C. Agardh Synops Alg. Scand. ix (1817). 



Orders Diatomeae and Fucoideae C. Agardh Syst. Alg. xii, xxxv (1824). 



Stamme Diatomea and Fucoideae Haeckel Gen. Morph. 2: xxv, xxxv (1866). 



Stamme Zygophyta in part and Phaeophyta Wettstein Handb. syst. Bot. 1: 71, 

 171 (1901). 



Divisions Zygophyceae in part and Phaeophyceae Engler Syllab. ed. 3: 8, 15 

 (1903). 



Chysophyta, with subordinate groups Chrysophyceae, Bacillariales, and Hetero- 

 kontae, Pascher in Ber. deutschen bot. Gess. 32: 158 (1914). 



Stamm Chrysophyta Pascher in Siisswasserfl. Deutschland 11: 17 (1925). 



Phyla Chrysophycophyta and Phaeophycophyta Papenfuss in Bull. Torrey Bot. 

 Club 73: 218 (1946). 



Organisms typically living by photosynthesis, without chromoprotein pigments, 

 the plastids containing chlorophylls a and c, carotin, and various xanthophylls. Lutein 

 (the xanthophyll of typical plants) may be present but is usually exceeded in quantity 

 by flavoxanthin, violoxanthin, isofucoxanthin, or fucoxanthin, particularly the last. 

 The xanthophylls occur usually in quantity sufficient to give the organisms a yellow 

 or brown color. True starch is not produced. Many examples contain granules of a 

 white solid called leucosin, presumably a carbohydrate, which does not give a blue 

 color with iodine. The cells are usually enclosed in walls consisting of cellulose to- 

 gether with larger quantities of other carbohydrates or oxidized or esterized carbo- 

 hydrates. Silica or calcium carbonate may be deposited. Methanol extracts of the 

 cells contain fucosterol, a sterol distinct from the sitosterol of typical plants. Flagel- 

 late cells are usually produced; these bear one pantoneme or pantacroneme flagellum, 

 and usually, in addition, one acroneme or simple flagellum. Exceptional examples, 

 non-pigmented or without flagellate stages, are rather numerous. The obvious stand- 

 ard genus of the phylum is Fucus L. 



The chemical characters are stated on the authority chiefly of Carter, Heilbron, 

 and Lythgoe (1939), Miwa (1940), and Tseng (1945). The character of the flagel- 

 lation, positively known of rather few examples, is stated by authority of Petersen 

 (1929), Vlk (1931, 1939), Couch (1938, 1941), Longest [1946), Manton (1952), 

 and Ferris (1954). 



These characters bind together an assemblage of organisms which is in some re- 

 spects original herel. Engler (1897), West (1904), and Smith (1918, 1920) included 

 the chrysomonad flagellates in the group of brown algae. Pascher (1914) combined 

 as or!e group the chrysomonads, the diatoms, and the exceptional green algae called 

 Heierokontae. Later (1927, 1930), he included also the colorless flagellates of family 

 Moiiadina. He did not associate this group with the brown algae, and subsequent 

 authors have in general followed him. Kylin ( 1933 ) , however, considered the diatoms 

 to be the closest allies of the brown algae, both groups being descended from the 

 brown flagellates. Almost certainly, he was correct. Couch showed that the paired 

 unlike flagella of the typical Oomycetes are respectively pantoneme and acroneme, 



iManton (1952) recognized this group, but omitted nomenclatural formalities. 



