THE MARINE ALG^ OF GUERXSEY 21 



Thallus prostrate and eree})ini^, adHxed to the substratum 

 by its under surface, rounded and gradually tapering. Apex 

 incurved, ecorticate. Branching alternately on either side, 

 and then afterwards irregulai-ly. 12-18 pericentral siphons. 

 Stichidia formed in the terminal segments of the branches, 

 slightly incurved, enclosing a double longitudinal series of 

 tetrasporangia. Cystocarps and antheridia hitherto unknown. 

 Cfe)iosipho)iia dift'ers from Folysiphouia by the arrange- 

 ment of the teti-asporangia, which form two longitudinal series 

 within the stichidium ; on account of this, the genus approaches 

 in a certain measure to Ralopitliys, but differs from it in the 

 number of pericentral siphons. Colour, a dull purple, turning 

 black when dry. 



C liypnoides was found In chinks of rock at half-tide in an 

 exposed locality and is a new arrival on the coasts of Britain. 

 Dense mossy tufts of dull purple filaments, about | inch high, 

 were closeh^ matted and entangled ; they measured 1-2 inches 

 across and held sand, small shells, and stones in their meshes, 

 serving as a shelter for spores of other algae. The specimens 

 were gathered in autumn, and did not show any reproductive 

 bodies. The plant is a native of S^jain, Portugal, and 

 Morocco. 



Dasya coeymbifera Crn. {Dasya venuata Harv.). Miss 

 Le Lievre's list. 



D. ARBUscuLA Ag. [E. 10, 11. N. W. 4.] E. 2, 6, 8. S. 2, 5. 

 N. 2. N.W.3.— (c.i.) var. ccsspitosa J. Ag. S. 2. 



Heterosiphonia plumosa Batt. {Dasya cocci nea Ag.). c. 

 S. 3. On rocks and stones. 



Sphondylothamniox multifidum Nag. a. S. 3. E. 6, 8, 9. 

 Hanging from rocks. 



Spermothamxion Turneri Aresch. {CalUthamnion Turneri 

 Ag.). f.c. Vertical rocks. [W. 5. N.W. 5. E. 2, 10.] S.W. 

 W. 2, 4. S. 2, 5. E. 6. N. W. 4.— (c.i.) var. monoica Schm. 

 {Call. Turneri var. variahile J. Ag. ; var. repens Auct. ; 

 S. roseolum Pringsh.). S. 1, 2, 4. N.W. 1. W. 1, 5. N. 2. 

 c. On Fucks serrafus and Furcell. fastigiata. — (c.i.) var. 

 svhverticlUatam Cotton. E. 11. v.r. 



This was added to the British Flora by Mr. A. D. Cotton. 

 Some small specimens were dredged at Bee du Nez in 1911 

 and 1912. 

 c.T. S. trregulare Ardiss. v.r. E. 10. W. 3. 



Ptilothamniox pluma Thur. {Qall. pliima Ag.). [S. 5.] 

 N.W. 5. W. 1. On Lam. Clousfoni. 



Gkiffithsta corallinoides Batt. {Griffitlisia corallina Ag.). 

 f. N. 2. E. 2. On rocks. 



Gr. FLOSCULOSA Batt. {G. setacea Ag.). c. E. 2. W. 1. 



Halurus equisetifolius Kiitz. ( G. eg^uiseti folia Ag.). [N.W. 

 4. E. 2.] W. 2, 4, 7. On rocks. 



Bornetia secundiflora Thur. {G. secundiflora J. Ag.). 

 [N.W. 4. 8. 3. E. 10, 11. W. 4.] E. f. N.W. 3. On 

 vertical rocks. (Fig. 5. ) 



