Arclucvlogij, tCr., of the May Island. 121 



Laiireucia pinnatitidti. 



„ liybrida. 

 Leathesia tuberitbrmis. 

 Callithamnion polysiiermuni, 



„ arbuscula. 



Ectocarpus tomentosus. 

 „ littoralis. 



„ siliculosus. 



„ spha^rophorus. 



Fucus vesiculosus. 

 „ serratus. 

 „ nodosus. 

 „ platycarpus. 

 „ canaliculatus. 



Halidrys siliquosiis. 

 Himantlialia lorea (two 



varieties). 

 Desraarestia aculeata. 

 Gigartina mammillosa. 

 Chondrus crispus. 

 Furcellai-ia fastigiata. 

 Polyides rotundus. 

 Odonthalia dentata. 

 Ralfsia deusta. 

 Petrocelis cruenta. 

 Melobesia pustulata. 



,, calcarea. 

 Hildenbrandtia rubra. 



The more noteworthy points connented with the flora appear 

 to be the following: — 



1. The entire absence of trees, whose roots play so important 

 a part in aiding in the disruption of rocks and the formation 

 of soils, and whose leafy branches prevent at once rapid radia- 

 tion and excessive warmth wliile they harbour many insects, 

 and modify the conditions of exposure as regards wind currents. 



2. The occurrence of Porphyra and young Edocarpi para- 

 sitically on Desmarestia aculeata — the former being attached 

 to the aculei of that plant. 



3. The occurrence of a large growth of Enteromorpha intestin- 

 alis in a pool above the limit of high spring tides, and so 

 furnished with saline matter exclusively by the agency of 

 spray — a fact which is to be correlated with the usual mode 

 of occurrence of this species in places where fresh water streams 

 enter the sea. 



4. The localisation of Pundaria plantaginea, which was 

 found only at the level of high tide on the south-east, seaward, 

 side of the island. 



5. The very large vegetative development of Cladophora 

 arcta and C. uncialis. 



6. The abundance of Plocamium coccineum, of which, how- 

 ever, no specimen was found growing, and which must have 

 come as drift from deep water. 



The inaccessible character of the rocks on the west side of 

 the island rendered the collection of Alga; impossible over a 

 considerable area of this margin. 



