Fucus Mackaii was discovered in the year 1805, on the western 

 coast of Ireland, by Mr. James Townsend Mackay, author of the 

 Flora Hibernica ', in honour of whom the species has been 

 named by Mr. Dawson Turner in his great work, the ' Historia 

 Fucorum \ For a long time the fructification remained undis- 

 covered, and, consequently, a doubt rested on the validity of the 

 species, the resemblance, in many respects, to a dwarfed variety 

 of Fucus nodosus suggesting a probability that it was only a form 

 of that plant. No doubt the connection between these plants is 

 very strong, yet the difference in ramification is so great, and the 

 constancy of character observed in Fucus Mackaii in many widely 

 distant localities in which it has been abundantly found, is so 

 remarkable, that added now to distinctions, afforded by the posi- 

 tion of the fruit, its characters are better established. Still, its 

 habitat is anomalous, and it may be urged that the peculiar 

 characters originate in this habitat. The Fuci in general are at- 

 tached by scutate roots to rocks and stones ; Fucus Mackaii in- 

 variably lies unattached, resting in its place, by its own weight, 

 on mud, gravel, or among loose boulders. In such situations it 

 flourishes from year to year, and fruits abundantly. 



The fruit was first observed by Dr. Greville in the autumn of 

 1842, in the collection of Mrs. Captain Maynard at Stanraer, to 

 whom it was communicated by Dr. Lindsay from the Isle of Skye. 

 More recently, in the Spring of 1846, Mr. Mc' Calla found an 

 abundance of specimens in fructification, which is, probably, 

 produced every year, but from the early season at which it is 

 formed, when few botanists have an opportunity of seeing the 

 plant, unless resident near its place of growth, the fruit has 

 hitherto escaped detection. From a fine specimen, communi- 

 cated to me by Mr. Mc' Calla, in a fresh state, my figure has been 

 taken, and I have since (in June) had the pleasure of gathering 

 fine fruiting specimens in the Sound of Skye. The pendulous 

 receptacles, produced at the bases of the main branches, and 

 the contrast between their clear greenish yellow, and the oliva- 

 ceous colour of the frond, have a very pretty effect. 



Pig. 1. Fucus Mackaii : — natural size. 2. Transverse segment of a receptacle. 

 3. A spore. 4. portion of the net-work from the centre of the receptacle: 

 — all highly magnified. 



