36 SYNOPSIS OF BRITISH BEAWSEDS. 



of which T have transferred from the excellent work of 

 Meneghini, all belong, as there is little doubt, to our plant, 

 it was firs! observed in the Mediterranean Sea, where it 

 appears to be not very uncommon, in several places. 



XXIII. PUNCTARIA. 



43. latifolia (The broad-leaf Punctaria) ; frond oblong or obo- 



vate, suddenly tapering at the base, pale olive-green, thickisb, 

 gelatinous and tender, Grev. Alg. Br. p. 52. (Atlas, PL XI. 

 Fig. 42.) 

 Phycolapathum debile, Ktz. 

 Hab. Rocks and stones in the sea. Annual. Summer. 



The genus Punctaria is exactly analogous among Dic- 

 tyotece to JJlva in Ulvacece, and so closely do its species 

 resemble the Ulvce in form and substance, that without 

 reference to fructification, or without a close examination 

 of the structure of the frond, a young botanist might some- 

 times confound the species of one genus with those of the 

 other. It requires also a careful examination to distin- 

 guish at all times between Laminaria debilis and Punctaria 

 latifolia, the form and colour of both being nearly identical. 

 The Laminaria is however, to the naked eye, more glossy, 

 and adheres much less firmly to paper ; and its structure, 

 instead of being reticulated, is closely cellular. This spe- 

 cies was founded in 1839 by Dr. Greville, and has since 

 been detected in tolerable plenty on several of our coasts. 



44. plant aginea (The Plantain Punctaria) ; frond lanceolate 



or obovato-lanceolate, cuneate and gradually attenuated at 

 base, brownish-olive, coriaceo-membranaceous, Grev. Alg. 

 Brit. p. 53. t. 9. (Atlas, PL XI. Fig. 43.) 

 Diplostromium plantagineum, Ktz. Zonaria plantaginea, Ag. 

 Ulva plantaginea, Roth. TJ. plantaginifolia, Wulf Lami- 

 naria plantaginea, Ag. 

 Hab. Xot uncommon on the English and Irish coasts. On rocks 

 and stones, between tide-marks, and in rocky tide-pools ; oc- 

 casionally on Alga?. Annual. Spring and summer. 

 By contrasting the figure of this with the preceding spe- 

 cies, the difference between typical forms of these plants 

 will be readily seen, the present being characterized by its 

 dark colour, cuneate base, and more lanceolate general 

 outline. I wish it could be said that such characters ad- 

 mitted of no approximation to their opposites. But though 

 specimens may be collected in plenty in which these peeu- 



