THE MARINE AUG.E OK NEW EXGLAXD. 99 



SiiboiHler FUCACE.E, C. Ag. 



Plants ditei'ioiis or hormaplirodito, fructifying orjj:ans borne in con- 

 ceptaoles or cavities lined with sterile lilanientsantl opening outwards by 

 a narrow pore ; antheridia in ovoid sacks borne on branching threads 

 and tilled with minute antherozoids having two lateral cilia ; oospores 

 spherical, borne 1-8 in a mother-cell. Marine plants of an olive-greeu 

 color, attached by a disk-like base, fronds usually branching dichoto- 

 mously, rarely indefinitely expanded, often provided with air-bladders 

 and with cryptostomata. 



Au order cluiractorizoil by tho prestMiro of autlu'ro/.oids homo in sacks and by 

 ooaporos, varying in the dilVerent genera from one to ei<;ht in a mother-cell, both an- 

 theridia and oospores being contained in hollow conceptacles, which are prodnced 

 either in detiuite parts of the frond or on special branches or rarely indetinitely scat- 

 tered over the frond. The fertilization in this order was first described by Thnret in 

 tho Annales des Sciences, Ser. 4, Vol. 2. The fronds vary very much in the ditferent 

 genera. In Dunilhra the frond resembles a largo Lamhiaria, and from this simple 

 form there are all degrees of complication, until in Sargaf^sum, the most highly devel- 

 oped genus, there are distinct stems, leaves, air-bladders, and branching fructiferous 

 receptacles. In high latitudes the order is chiefly represented by the common rock- 

 weeds, Fiici, which line tho rocks between tide-marks, while in low latitudes the 

 gulf-weeds, species of Sanjassum, abound. The Southern Ocean abounds in curious 

 and varied forms of this order, Australia being particularly rich in species. The \ew 

 England coast is especially poor in representatives of the order, the genera Halidrys, 

 EimanthaUa, Pelvetia, and Cystoseira, common on the coast of Europe, being entirely 

 wanting with us. The fronts are dotted with small pits, called cryptostomata, from 

 which grow tufts of hairs. 



SYNOPSIS OF GENERA. 



Fronds with distinct stems and leaves Sargassum. 



Fronds without distinct stems and leaves — 



Lamina provided with a midrib, receptacles terminal, continuous with 

 the frond Fucus. 



Midrib wanting, receptacles on special lateral branches. .AscophyUiun. 



ASCOPIIYLLUM, (Stackh.) Le Joli.s, emend. 

 (From aoKoc, a sack, and (pvA/.ov, a leaf.) 



Fronds attached by a di.sk, linear, compressed, destitute of a midrib, 

 irregularly dichotomous, furni.shed with air-bladders j receptacles on dis- 

 tinct, simple, lateral branches; spores four in a mother-cell. 



A genus including the Fucum nodosns of older writers, whi<h dilTt-rs from tlif true I'uci 

 in having a linear frond destitute of a midrib and .spores in fours instead of in eights. 

 The generic name OzothaUin proposed by Decaisne and Thnret, who were the first to 

 give a detailed account of the conceptacles of /•'. nodnsus, was referred by Le Jolis to 

 the older genus Aacophylla of Stackhouse. 



A. NODOsmi, Le Jolis. {Fucus noilosus, L.j Pliyc. Brit., PI. l.'iS; Ner. 



