56 CHLOROPHYCEAE 



for a few species, and in such cases the oospores may remain dormant 

 for several years before they produce one to four biflagellate swarmers 

 which very soon come to rest and then grow into new plants. On 

 germination the zoospores do not always separate and so one gets 

 a four- or eight-flagellate synzoospore depending on whether it is 

 composed of two or four zoids. These germinate to a fourfold 

 seedling or to a seedling with four claws. In some cases the swarmers 

 in the oospore are completely suppressed and a new filament develops 

 directly, this type of reproduction being known as azoosporic. The 

 adult plants are haploid because meiosis is known to take place at 

 the segmentation of the oospore. 



Primitive characters, which seem to be a feature of the genus, 

 are the numerous ova, the entire lack of specialized organs for pro- 

 ducing the sexual reproductive bodies and a simple form of zygote 

 germination, whilst in S. tenuis the reproduction is even more 

 primitive as there is strong evidence to show that both kinds of 

 gametes are motile. The plant must probably be regarded as an 

 Ulotrichacean filament, which, whilst becoming non-septate, has 

 still retained, many primitive features, and in *S. annulina cells are 

 frequently found with only one or two chloroplasts thus showing 

 a gradation towards Ulothrix. There would seem to be very little 

 justification for following some authors and placing it in either the 

 Siphonales or Siphonocladiales, though it must be admitted that 

 S. Africana does have some features in common with those of the 

 Siphonocladiales. 



REFERENCES 



Enter omorpha. Eliding, C. (1933). Svensk hot. Tidskr. 27, 233. 

 Ulvaceae. Carter, N. (1926). Ann. Bot., Lond., 40, 665. 

 Sphaeroplea. Fritsch, F. E. (1929). Ann. Bot., Lond., 43, i. 

 Ulothrix. Gross, I. (193 1). Arch. Protistenk. 73, 206. 

 Enter omorpha. Hartmann, M. (1929). Ber. dtsch. hot. Ges. 47, 485. 

 Prasiola. Knebel, G. (1935-6). Hedwigia, 75, i. 

 Monostroma. Kunieda, H. (1934). Proc. Imp. Acad. Tokyo, 10, 103. 

 Enteromorpha Kylin, H. (1930). Ber. dtsch. bot. Ges. 48, 458. 

 Ulothrix. LiND, E. M. (1932). Ann. Bot., Lond., 46, 711. 

 Microspora. Meyer, K. (1913). Ber. dtsch. bot. Ges. 31, 441. 

 Sphaeroplea. Pascher, A. (1939). Beih. hot. Zhl. 59, Abt. A., 188. 

 Microspora. Steinecke, F. von (1932). Bot. Arch. 34, 216. 

 Prasiola. Yabe, Y. (1932). Sci. Rep. Tokyo Bunrika Daig. i, 39. 



