FUCOIDE^E. 



[ 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 during the locomotion the corpuscle 

 turns upon its own axis, with the longer 

 cilium in advance, vibrating with rapidity, 

 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 Fucaceae 

 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-coloured spores. (See Fu- 



CACEvE.) 



Synopsis of the Tribes. 



1. FUCACE^B. Frond leathery or membra- 

 nous, cellular. Fructification: spores and 

 antheridia contained together or separately 

 in spherical cavities imbedded in the frond. 



2. DICTYOTACE^E. Frond cellular, flat, 

 compact. Fructification : spores arranged in 

 definite spots or lines (sori) on the sur- 

 face. 



3. CUTLERIACE.E. 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^E. 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^E. 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^J. Frond cylindrical or 

 flat, unbranched, cellular. Fructification : 

 ovate oosporanges in groups on the surface, 

 intermixed with clavate filaments (para- 

 physes). 



7. SPOROCHNACE^E. 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^E. 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^E. Frond 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^E. 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 Fucacea; (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. 



