FRO 



and fruit are produced from the 

 leaf itself. 



2. The herbaceous parts of flower- 

 less plants, resembling leaves, are 

 called fronds ; they differ from true 

 leaves in their structure in many 

 respects. 



FBONT. (front, Fr. fronte, It.) In 

 eonchology, when the aperture in 

 univalves is turned towards the 

 observer. 



FBO'NTAL. ffrontale, Lat. frontal, Fr. 

 frontale, It.) Appertaining to the 

 forehead. 



FBTJCTIFICA'TION. (fructification, Fr. 

 fruttificazidne, It.) 



1 . The temporary part of a vegeta- 

 ble appropriated for generation, 

 terminating the old vegetable, and 

 beginning the new. It consists of 

 the following parts; namely, the 

 calyx, corolla, stamen, pistillum, 

 pericarpium, semen, and recepta- 

 culum. 



2. The act of bearing fruit; fer- 

 tility; fecundation. 



F'FCHSITE. A variety of mica con- 

 taining chrome. 



FU'COID. (from 0<kos and eidos, Gr.) 

 A species of fucus. Fucoids are 

 very abundant in many of the 

 strata, occurring in the transition 

 strata of North America in nume- 

 rous thin layers. An account of 

 these has been published by Dr. 

 Harlan, of America, and by Mr. 

 B. C. Taylor, in London's Magazine 

 of Natural History. Fucoids are 

 found in great abundance in the 

 granwacke slate of the Maritime 

 Alps, in the lias, and in the chalk. 

 There is one species, the Fucoides 

 targionii, that abounds in the 

 upper green- sand. To a fine 

 species, discovered in the chalk by 

 Dr. Mantell, he has given the 

 name Fucoides Brongniarti. 



Fu'cvs. (fucus, Lat. 0t)/co?, Gr.) 

 A genus of the order of Algae, 

 belonging to the class Cryptogamia. 

 This genus comprehends most of 



[ 182 ] FUR 



those plants commonly called 

 weed : pi ; fuci. 



cfLQOBiTE. (/ulguritm, Lat.) Any- 

 thing struck by lightning. Rocks, 

 and the tops of mountains, often 

 bear the marks of fusion from the 

 action of lightning ; and occasion- 

 ally vitreous tubes, descending 

 many feet into banks of sand, 

 mark the path of the electric fluid. 

 Some years ago, Dr. Fiedler exhi- 

 bited several of the fulgorites in 

 London, which had been dug out 

 of the sandy plains of Silesia and 

 Eastern Prussia. Mrs. Somerville. 

 " In a broad land of sand-hil- 

 locks," says Mr. Darwin, "which 

 separate the Laguna del Potrero 

 from the shores of the Plata, at the 

 distance of a few miles from Mal- 

 donado, I found a group of those 

 vitrified, siliceous tubes, which are 

 generally supposed to have been 

 formed by lightning entering the 

 loose sand. These tubes resemble 

 in every particular those from 

 Drigg in Cumberland, described in 

 the second vol. of the Geological 

 Transactions. The internal surface 

 is completely vitrified, glossy, and 

 smooth. A small fragment ex- 

 amined under the microscope, ap- 

 peared, from the number of minute 

 entangled air, or, perhaps, steam 

 bubbles, like an assay fused before 

 the blow-pipe. The sand is en- 

 tirely, or in greater part, siliceous ; 

 but some points are of a black 

 colour, and from their glossy sur- 

 face possess a metallic lustre. The 

 thickness of the wall of the tube 

 varies from a thirtieth to a twenti- 

 eth part of an inch, and occasionally 

 even equals a tenth. On the out- 

 side, the grains of sand are rounded, 

 and have a slightly glazed appear- 

 ance : the tubes are generally com- 

 pressed, and have deep longitudinal 

 furrows, so as closely to resemble a 

 shrivelled vegetable stalk, or the 

 bark of the elm or cork tree. Their 

 circumference is about two inche B; 



