FUCOIDE.E. 



[ 339 ] 



FUCUS. 



form of the antlierozoids is not clearly made 

 out. The antherozoids of the Fucacefe have 

 been shown by Thuret, their discoverer, to 

 be analogous to the spermatozoids of the 

 higher Cryptogamia, and to perform a ferti- 

 lizing function — not to reproduce the plant 

 like the zoospores of the other families ; 

 and the multiplication appears to be effected 

 solely by the large olive-coloured spores. 

 (SeeFucACEiE.) 



Spwpsis of the Families. 

 FuCACK^.. Frond leathery or mem- 

 branous, cellular. Fructification : spores and 

 antheridia contained together or separately 

 in spherical cavities imbedded in the frond. 

 DiCTYOTACE.^. Frond cellular, flat, 

 compact. Fructification : spores, antheridia 

 (and tetraspores?) arranged in definite spots 

 or lines (sori) on the surface. 



CuTLERiACEiE. Froud cellular, com- 

 pact, ribless. FrnctiJjcatio7i : dot-like scat- 

 tered collections of sporanges divided into 

 eio-ht compartments ; and antheridia con- 

 sistino- of chambered filaments in groups of 

 curved jointed hairs. 



EcTOCAHPACE^. Frond filiform, jointed. 

 Fructification: unilocidar sporanges, ovate 

 sacs developed at the ends or intermediate 

 ioints of the filaments; and multi/ocidar 

 sporanges, consisting of minute jointed 

 filaments found in similar situations. An- 

 theridia Avith spermatozoids have been 

 foimd in Sphacelaria. 



LAMiNAEiACEiE. Frond leathery or gela- 

 tinous, cellular. Fructification : unilocnlar 

 sporanges in indefinite cloud-like patches, 

 or covering the whole surface of the frond ; 

 or nndtilocular sporanges clothing the whole 

 surface of the frond like an epidermis. 



DiCTYOSiPHONACE^. Frond cylindrical, 

 branched, of filamentous structure. Fruc- 

 tification : ovoid sporanges imbedded length- 

 ways in the substance of the frond, opening 

 by a pore on the surface. 



PrxCTARiACE^B. Frond cylindrical or 

 flat, unbranched, cellular. Fructification: 

 ovate sporanges in groups on the surface, 

 intermixed with clavate filaments (jpara- 



physes). 



SpoROCHNACEiE. Jy-dMfZ leathciy or mem- 

 branous, cellular, branched. Fructification ; 

 uniloadar or multilncular sporanges attached 

 to external jointed filaments, free or collect- 

 ed in knob-iike masses. 



Choedaeiace^. Frond cartilaginous or 

 gelatinous, composed of horizontal and ver- 

 tical jointed filaments interlaced. Fructifi- 



cation : nnilocular sporanges springing from 

 the base of the vertical filaments forming 

 the epidermis of the frond; and mtdtilocrdar 

 sporanges developed later from the filaments 

 surrounding the former. 



MvRiONEMACEiE. Frotid tuber-shaped, 

 crustaceous, or spreading as a crust, of fila- 

 mentous strncture. Fructification : nnilocular 

 and multilocular sporanges attached to the 

 superficial filaments, and concealed among 

 them. 



BiBL. See that of the Families. 



FU'CUS, Linn. — A genus of Fucaceee 

 (Fucoid Algae), including some of the com- 

 monest and most abundant of our olive- 

 coloured sea-weeds, growing upon rocks 

 and stones between tide-marks, their large 

 fronds waving in the water at high tide, 

 and lying matted together over the rocks 

 when the tide is out; continually cast 

 ashore in quantities after rough weather. 

 F. vesiculosus, the common bladder-icrack, is 

 familiar to every one who has visited a sea- 

 coast. Decaisne and Thuret divide the 

 genus into three: Pelvetia{F.canalicidattis), 

 Ozothallia (F. nodosus), and Fiicus proper, 

 including F. serratus, vesiculosus, and cera- 

 noides. 



In F. nodosus and F. Machaii the recep- 

 tacles are lateral and stallied ; but in all the 

 rest they are terminal and continuous with 

 the frond (fig. 252), forming oval thickened 



Fiff. 252. 



End of a branch of F. vesiculosus, bearing two terminal 



receptacles. 



Half the nat. size. 



clubs, on which, by the naked eye, may be 

 distinguished a number of spots or pores. 

 These are the orifices of the conceptacles, 

 which are globular cases immersed in the 

 substance of the receptacle, and communi- 

 cating with the outer surface by a pore (fig. 

 263). The central portion of the receptacle 



z2 



