THE MARINE ALG.E OF NEW ENGLAND. 99 



Suborder FUCACE^E, C. Ag. 



Plants dioecious or hermaphrodite, fructifying organs borne in con- 



ceptacles or cavities lined with sterile filaments and opening outwards by 



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



and filled with minute antherozoids having two lateral cilia ^oospores 



spherical, borne 1-S in a mother-cell. Marine plants of an olive-green 



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



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



and with cryptostomata. 



An order characterized by the presence of antherozoids borne in sacks and by 

 oospores, varying in the different genera from one to eight in a mother-cell, both an- 

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

 either in definite parts of the frond or on special branches or rarely indefinitely scat- 

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

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

 genera. In Durvillcea the frond resembles a large Laminaria, and from this simple 

 form there are all degrees of complication, until in Sargassum, 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, Fuel, which line the rocks between tide-marks, while in low latitudes the 

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

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

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

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

 wanting with us. The fronds 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. .Ascophyllum. 



ASCOPHYLLUM, (Stackh.) Le Jolis, emend. 

 (From aanog, a sack, and tyvXkov, a leaf.) 



Fronds attached by a disk, linear, compressed, destitute of a midrib, 

 irregularly dichotomous, furnished with air-bladders ; receptacles on dis- 

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



A genus including the Fucus nodosus of older writers, which differs from the true Fuel 

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

 The generic name Ozothallia proposed by Decaisne and Thuret, who were the first to , 

 give a detailed account of the conceptacles of F. nodosus, was referred by Le Jobs to 

 the older genus Ascophylla of Stackhouse. 



A. NODOSUM, Le Jolis. (Fucus nodosus, L. ; Phyc. Brit., PI. 158 ; Ner. 



