306 Mr George Traill on the 



November to August. Fruit in winter and spring. Spores escape 

 in May and June. Kirkwall and Scapa I'>ays, 1887 (G. W. T.). 

 Corroborated by Prof. Lornet, Paris. 



23. TJl othrix isogona (i^Hg'. Bot.), Tliur. (Lynghya speciosa, Carm.) 

 Associated with the preceding. Annual. November to August. 



Fruit in winter and spring. Spores escape in May and June. 

 Kirkwall and Scapa Bays, 1887 (G. W. T.). Corroborated by Prof. 

 Kjelhnan, Upsala. 



RHIZOCLONIUM, Kiitz. 



24. Rhizoclonium riparium (Roth), Harv. 



On sand-covered rocks, and sometimes epiphytic on Algae, near 

 high-water mark. Occasionally forms widely-spreading strata in 

 quiet, flat, sandy or muddy places near high-water mark. Left 

 uncovered by the tide, and exposed to the light for many hours 

 daily. All the year. " Peerie Sea," Kirkwall, and west side of 

 Scapa Bay (G. W. T.). Corroborated by E. M. Holmes. 



CLADOPHORA, KUtz. 



25. Cladophora arcta (Dillw.), Kiitz. 



In pools near low- water mark. Always submerged. Annual. 

 March to October. Shapansey, fine ; Rousay, opposite Wire, fine 

 and abundant ; Black Craig. The variety centralis of Lyngbye 

 also occurs at Rousay, among other places. 



26. Cladophora lanosa (Roth), Kiitz. 



Near low-water mark ; usually epiphytic on Algas. Always 

 submerged. Annual. Spring to the end of autumn. Carness Bay, 

 in pools opposite Hellyar Holm. 



26a. Cladophora lanosa, var. iincialis (Harv. ), Thur. 



On flat rocks and stones near low- water mark, exposed to the 

 light. Annual. Usual duration from beginning of spring to end 

 of autumn, some plants apparently lasting through winter. In best 

 condition in July. Old plants lose their gloss, and become lighter 

 in colour. Occurs, among other places, at the east of Providence 

 Gjio, in Rousay, very fine. 



27. Cladophora rupestris (Linn.), Kiitz. 



Common on rocks between tide marks, and at a lower level. 

 Rarely epiphytic on Algae. All the year. Fruit in summer. 



28. Cladophora pellucida (Huds.), Kiitz. 



In pools, generally near low- water mark. Annual. Summer 

 Found by Mr PoUexfen. 



29. Cladophora Hutchinsise (Dillw.), Harv. 



On the rocky bottoms of clear tide pools near low- water mark. 

 Annual. Summer. Found by Mr Pollexfen. 



