FUCOIDE^. 



[ 276 ] 



FUCUS. 



and Cystoseira, the corpuscle is oval or sphe- 

 rical in one dimension, and compressed, 

 sometimes a little convex, in the other; 

 both the cilia are inserted on the red granule, 

 and dm-ing the locomotion the corpuscle 

 turns upon its own axis, with the longer 

 cilium in advance, vibrating with ra])idity, 

 while the shorter is motionless. In Himan- 

 thalia the antheridia have a double coat; the 

 form of the antherozoids is not well under- 

 stood. The antherozoids of the Fucacese 

 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 tribes ; in 

 these plants this appears to be effected solely 

 by the large olive-colom'ed spores. (See Fu- 



CACE^.) 



Synopsis of the Tribes. 



1. FucACEiE. Frond leathery or membra- 

 nous, cellular. Fructification : spores and 

 antheridia contained together or separately 

 in spherical cavities imbedded in the frond. 



2. DiCTYOTACE^. Frond cellular, flat, 

 compact. Fructification : spores arranged in 

 definite spots or lines {sori) on the sur- 

 face. 



3. CuTLERiACE^. Frond cellular, com- 

 pact, ribless. Fructification : dot-like, scat- 

 tered collections of oosporanges divided 

 in eight compartments ; and antheridia, 

 consisting of chambered filaments in groups 

 of curved jointed hairs. 



4. Laminariace^. Frond leathery or 

 gelatinous, cellular. Fructification : oospo- 

 ranges in indefinite cloud-like patches, or 

 covering the whole surface of the frond ; or 

 trichosporanges clothing the whole surface 

 of the frond like an epidermis. 



5. DicTYOSiPHONACE^. Frond cylin- 

 drical, branched, of filamentous structure. 

 Fructification : ovoid oosporanges imbedded 

 lengthways in the substance of the frond, 

 opening by a pore on the surface. 



6. PuNCTARiACE^. jPro?i£^ cvliudrical or 

 flat, unbranched, cellular. Fructification : 

 ovate oosporanges in groups on the surface, 

 intermixed with clavate filaments {para- 

 physes). 



7. SpoROCHNACEiE. Frond leathery or 

 membranous, cellular, branched. Fructifi- 

 cation : oosporanges or trichosporanges at- 

 tached to external jointed filaments, free or 

 collected in knob-like masses. 



8. Chordariace^. Frond cartilaginous 

 or gelatinous, composed of horizontal and 



vertical jointed filaments interlaced. Fruc- 

 tication : oosporanges springing from the 

 base of the vertical filaments forming the 

 epidermis of the frond; and trichospo- 

 ranges developed later from the filaments 

 surrounding the oosporanges. 



9. Myrionemace^. Fro ?ic/ tuber-shaped, 

 crustaceous, or spreading as a crust, of 

 filamentous structure. Fructification : 

 oosporanges, and trichosporanges attached 

 to the superficial filaments, and concealed 

 among them. 



10. EcTocARPACE^. Frond filiform, 

 jointed. Fructification : oosporanges, ovate 

 sacs developed at the ends or interme- 

 diate joints of the filaments; and tricho- 

 sporanges, consisting of minute jointed fila- 

 ments found in similar situations. 



BiBL. See under the Families. 



FUCUS, Linn. — A genus of Fucacese (Fu- 

 coid Algae), including some of the commonest 

 and most abundant of our olive-coloured sea- 

 weeds, growing upon rocks and stones be- 

 tween tide-marks, their large fronds waving 

 in the water at high-water, 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-wrack, is familiar to every one who 

 has visited a sea-coast. Decaisne and Thu- 

 ret divide the genus into three : Pelvetia 

 {F. canaliculata), Ozothallia {F. nodosus), 

 and Fucus proper, including F. serratus, 

 vesiculosus and ceranoides. 



In F. nodosus and F. Mackaii the recep- 

 tacles are lateral and stalked, but in all 

 the rest they are terminal and continuous 

 with the frond (fig. 256), forming oval, thick- 

 Fig 256. 



F. vesiculosus. 



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

 receptacles. 



Half the nat. size. 



