THE MARINE BOTANIST. 40 



grouped together on the surface of the fronds into 

 distinct spots or lines. 



The reticulated or net-like structure of the fronds, 

 and peculiar disposition of the spores, readily dis- 

 tinguish these plants from the foregoing tribe. 

 Some of the species are of great beauty and rarity. 

 Padina Pavonia is only found on the south coast of 

 England, this is its northernmost limit ; throughout 

 the tropics, and along the shores of Southern Europe, 

 it is an abundant species. The shape of the frond, 

 and the markings on the surface, causes the plant 

 when dry to resemble very much the common fungus, 

 Polyporus versicolor. When growing it is very beau- 

 tiful, and the fronds are clothed, as are many 

 others of the tribe, with very fine hairs, which often 

 decompose the rays of light, reflecting prismatic 

 colours. Haliseris Polypodiodes is the only species 

 furnished with a midrib ; it is an elegant plant of a 

 pale yellow colour, and when recent emitting a 

 remarkable scent; after drying this is not ob- 

 servable. Twelve genera are included in the 



