ULYACE^E. 
53 
I. POEPHYEA. Ag. 
Frond membranaceous, flat and leaf-like, purple. Fructification , dark purple gra- 
nules (spores) arranged in fours, dispersed over the whole frond. 
The species of this genus are difficult to determine, and I am induced, in this place, 
to unite the P. vulgaris and P. laciniata of authors, which I have elsewhere ( Phyc . 
Brit.) figured and described as distinct. They appear to me to run one into another ; 
and if we contend for two species, with equal justice might we make half-a-dozen. Both 
are indifferently used in England in the preparation of “ marine sauce? or laver, which 
is often brought to table as an accompaniment to roast meat. Kiitzing describes 
sixteen species, several of which are probably reduceable to the following : — 
I. Porphyea vulgaris , Ag. ; frond polymorphous, either undivided or cleft into 
several broad segments ; sometimes peltate, fixed by a middle point. P. purpurea , and 
P. laciniata , Ag. Sp. Alg. p. 190 — 191. P. vulgaris , Ag. Aufiz. p. 18. Harv. 
Phyc. Brit. t. 211. P. laciniata , Harv. Phyc. Brit. t. 92. Wyatt. Alg. Danm. 
No. 32. P. linearis , Grev. P. amethystea , Kiitz. 
Hab. Eocks between tide marks. On the eastern shores from Charleston, South 
Carolina, to the Arctic Eegions. Western Coast, from California to Eussian America 
(v. v.). 
Very variable in form in different localities and at different stages of growth. In an 
early state it is either oblong or linear-lanceolate, with an evident though minute 
stipes, and then it constitutes the P. linearis of Greville, which is found truest to its 
type in the beginning of winter, in situations near high-water mark, where its vegeta- 
tion is less vigorous. Later in the season the form usually called P. vulgaris , as 
figured in Phyc. Brit. t. 211, will be found in the same locality, and also throughout 
the whole space between tide marks. In this the frond is ovate or ovato-lanceolate, or 
broadly lanceolate, much waved at the margin, and without obvious stipe, several inches 
long and 2-3 inches wide. P. laciniata , Ag., which merely differs in having a deeply 
lobed or divided lamina, grows mixed with the simple variety (P. vulgaris ) ; and 
specimens may easily be found which are intermediate in character. The state called 
P. umbilicalis grows on exposed rocks, generally near low water mark, and looks more 
like a different species than any of the other varieties. In it the frond is always short, 
usually of a very dull colour, fixed by a point removed from the margin of the lamina, 
and therefore somewhat peltate, with the upper side depressed or umbilicate in the 
centre. This variety is rarely more than two or three inches in length. Other varieties 
attain to 8 or 10 inches or more. 
The colour varies with the age and condition of the fronds. Often it is olivaceous 
green, with little or no trace of purple ; but generally it is of a fine dark purple, 
