848 DR, SARAH М, BAKER AND MISS M. H. BOHLING ON 
Table showing Relationships between Rock and Mud Species. 
Rock Species. | Mud Form. Habit. | Attachment. Reproduction.) 
Pelvetia Megecad limicola. | 
canaliculata, | ecad radicans. Dwarf. Embedded & rhizoids. | Vegetative. 
ecad coralloides. | Dwarf, coralline, | Embedded. Vegetative. 
ecad libera. Curled. Free. Vegetative. 
Fucus var. nana. Dwarf. Disc or rhizoids. Normal. 
spiralis. 
Ascophyllum | var. minor. Dwarf. Embedded. Normal, 
nodosum. Megecad /imicola. 
ecad scorpioides. | Dwarf, curled. Embedded or free. Vegetative. 
ecad Маскат. Dwarf. Free. Normal. 
Fucus | Megecad limicola. 
vesiculosus. 
Marsh Section. | Crypts marginal, 
ecad volubilis. Spiral, gen. dwarf. Embedded. Vegetative. 
ecad cespitosus. | Dwarf. Embedded. Vegetative. 
ecad muscoides. | Very dwarf. Embedded. Vegetative. 
Loose-lyingSection.| Crypts variable. | 
| 
| ecad nanus. Dwarf, flexuous, | Free. Vegetative. 
| T . 
| ecad subecostatus. | Dwarf, crypts Free. Vegetative. 
marginal. 
| ecad filiformis. | Very dwarf, | Free, Vegetative. 
crypts absent. 
Fucus | Megecad limicola. | Dwarf and | ‘mbedded or free. Vegetative. 
ceranoides. | curled. 
Fucus | Mececad limicola. | Dwarf and Free. Normal or 
inflatus. | ecad membrana- curled. | vegetative, 
ceus, 
For the sake of convenience a uniform series of diagnoses has been 
drawn up to include the British salt-marsh forms, as well as the loose-lying 
forms. The specific diagnoses are from Rabenhorst’s * Kryptogamen- 
Flora von Deutschland,’ or Harvey's * Phycologia Britannica, with slight 
modifications, where references to the literature on each species will be 
found. 
DIAGNOSES. 
PELVETIA CANALICULATA (L.) ; Decne. & Thur. 
Frond linear, narrow, channelled on one side, without midrib or air- 
vesicles, dichotomous, 5-20 ems. in length, 2-3 mm. broad ; attached by disc. 
Receptacles terminal, bipartite. Hermaphrodite. The oogonium produces 
two oospores. 
