A very charming plant, though a common one; common, not 
merely on the shores of Europe, but dispersed far and wide 
through the ocean, north and south of the Line. Dr. Hooker 
gathered it at Cape Horn, and Mr. Gunn has sent it from Van 
Dieman’s Land. I have examined specimens from these distant 
habitats, and compared them with those from our own shore, 
and can detect no specific distinctions. The characters of the 
species are indeed strongly marked, and once seen, cannot be 
forgotten. Would that others of this beautiful genus were 
equally constant! It would save botanists a world of trouble 
and uncertainty. Here every articulation, without exception, 
through the whole plant, bears its pair of comb-like branchlets. 
Under the microscope, therefore, Cal. Plumula cannot well 
be mistaken. But, notwithstanding this perfect regularity of 
branching, specimens differ much in luxuriance, and consequently 
in outer aspect; and we might enumerate ¢wo varieties, m one 
of which the combs are twice as long as in the other, and more 
delicate. 
Cal. simile of the Antarctic Flora, a native of Kerguelen’s 
Land, is an instance of a closely allied, and yet perfectly distinct 
species, and shows in a very forcible manner how similar two 
things in nature may be, without beg the same; how closely 
she can draw her lines without touching at any point ! 
Fig. 1. CaLLitHaMNion PiumuLa :—of the natural size. 2. Portion of a 
frond. 3. Portion of another specimen,-with favelle. 4. Favelle, with 
surrounding plumules. 5. Plumule, bearing ¢e¢raspores on its ultimate 
ramuli. 6. Penultimate ramulus from the same, with tetraspores :—all more 
or less highly magnified. 
