218 ALGyE RHODOSPERME^E. [Trentepohlia 



18. C. repens, Lyngb. Creeping Callithamnion. Stems 

 rising from creeping filaments, erect, sparingly branched; 

 branches alternate, patent, with a few short ramuli ; articula- 

 tions of the stem 3 6 times longer than broad. Harv. in Hook. 

 Br. Fl. v. ii. p. 348. Cow/, repens, Dillw. t. 18. E. Bot. 

 t. 1608. (the young plant.) 



On the larger Algae. I fear this is not sufficiently distinct from 

 some states of C. Turneri. 



56. TRENTEPOHLIA. Ag. Trentepohlia. 



Frond filamentous ; filaments (minute, mostly parasitical,) erect, 

 coloured, articulated ; dissepiments hyaline. Fructification 

 tufted, mostly terminal capsules. Named in honour of a 

 German Botanist. This appears to me a very natural little 

 group, though in essential character scarcely differing from 

 Callithamnion. The species are mostly minute parasites. 



* Growing in the sea, or on maritime rocks. 



1. T. Rothii, Harv. Roths Trentepohlia. Widely spread- 

 ing, densely caespitose ; filaments slender, short, erect, dichoto- 

 mous; branches elongate, straight, appressed; articulations 

 twice as long as broad. Callithamnion Rothii, Lyngb. Harv. 

 in Hook. Br. Fl v. ii. p. 347. Conf. Rothii, Dillw. t. 73. E. 

 Bot. t. 1702. 



Marine rocks, near high-water mark. Tufts 1 inch high, dense, 

 deep red or purple. Capsules clustered, borne on short terminal sub- 

 corymbose ramuli. 



2. T. floridulum, Harv. Pale-red Trentepohlia. Filaments 

 short, densely entangled, sparingly branched ; branches alter- 

 nate or subdichotomous, nearly simple, appressed; articulations 

 thrice as long as broad. Callithamnion florid. Ag. Harv. in 

 Hook. Br. Fl. v. ii. p. 348. Conf. florid. Dillw. Sup. t. F. 



Rocks near low-water mark, Galway Coast ; J. T. Mackay. An- 

 trim ; Dr. Scott. This, I imagine, is only C. Rothii, altered by 

 growing in deeper water. 



3. T. purpurea, Ag. Purple Trentepohlia. Filaments erect, 

 very minute, forming continuous, velvety patches, slightly 

 branched ; branches dichotomous ; articulations twice as long 

 as broad. Harv. in Hook. Br. Fl. v. ii. p. 382. Conf. pur- 

 purea, Dillw. t. 43. Byssus purpurea, E. Bot. t. 192. 



On rocks by the sea-coast, beyond high-water mark. Perhaps I 

 am incorrect, in introducing this species, (a native of the West of Scot- 

 land and England,) to the Irish Flora, without having a certain know- 

 ledge of its existence on our shores, though it is more than probable 

 that it abounds on the trap rocks of our northern and western coasts. 

 My apology for so doing is a desire to contrast it with T. Rothii and 



