108 BRITISH CHAROPHYTA. 



the plant appeared entirely male. On specimens collected 

 towards the end of June, the conditions were reversed, fully 

 formed oogonia being numerous and antheridia few, so that 

 the plant appeared female ; at intermediate dates the plant 

 was obviously moncecious. We have a very similar form 

 collected at Lund, and distributed under the name of 

 N.fiexilis f. incrustata. Here the state of things is much the 

 same as in our Fenland plant. On a specimen collected by 

 Wahlstedt in May, 1864, the antheridia are very large and 

 conspicuous, and the oogonia are little in evidence, while in 

 one collected in June of the same year by Olsson, oogonia are 

 numerous, and antheridia almost absent. In the Lund plant 

 also the tips of the rays are strongly mucronate. In these 

 forms there is clearly an approach to the dioecious condition. 

 The antheridia are very conspicuous not only on account of 

 their size but of their particularly brilliant orange-red colour. 

 We name this variety after the late Alfred Fryer, the eminent 

 Fenland botanist, who first found it in Cambridgeshire in 

 1884 and drew attention to its peculiar characteristics. 



4. Nitella spanioclema. 



Groves & Bullock-Webstee in Journ. Bot. LVII, p. 1, t. 551 (1919) ; 

 in Irish Nat. XXVIII, p. 2, t. 1 (1919). 



(Plates IX & X.) 



Monoecious. Stem slender, internodes usually 

 equalling or not much exceeding the branchlets. 

 Branches often three together, 1-2 apparently taking 

 the place of suppressed branchlets, often arrested, 

 and when elongating often producing rudimentary 

 whorls. Branchlets few, usually 2-B in a whorl, 

 normally once furcate, but often with a second node ; 

 lateral rays solitary, conspicuously shorter than their 

 axial rays, often rudimentary, very short and incon- 

 spicuous at the nodes producing antheridia. Ultimate 

 rays 1-celled, apex varying from acuminate to roundish 

 acute or bluntly mucronate. Oogonia and antheridia 

 together or at different nodes. Oogonia solitary or 

 2-3 together, c. 800-850 fi long, 640-680 fi broad; 

 spiral-cells showing 7 convolutions, swelling con- 

 siderably at the apex ; coromda c. 60 fi high, 

 deciduous. Oospore c. 475-500 jj, long, 425-450 /t 



