94s PHYSIOGNOMY OF PLANTS. 



taigne to the annual rings ; and he also maintained that the 

 rings were narrower on the north side of the tree. Jean 

 Jacques Rousseau had the same belief ; and his Emile, if he 

 loses himself in a forest, is to direct himself by the indica- 

 tions afforded by the relative thickness of the layers of wood. 

 More recent observations on the anatomy of plants teach us, 

 however, that both the acceleration and also the retardation 

 or intermission of growth, or the varying production of 

 circles of ligneous fascicles (annual deposits) from the Cam- 

 bium cells, depend on influences which are wholly distinct 

 from the quarter of the heavens towards which one side of 

 the annual rings is turned. (Kunth, Lelirbuch der Botanik, 

 1847, T. i. S. 146 and 164; Lindley, Introduction to Bo- 

 tany, 2d edition, p. 75.) 



Trees which in individual cases attain a diameter of more 

 than twenty feet, and an age extending to many centuries, 

 belong to the most different natural families. I may name 

 here Baobabs, Dragon-trees, some species of Eucalyptus, 

 Taxodium disticum (Rich.), Pinus Lambertiana (Douglas), 

 Hymensea courbaril, Ceesalpiniese, Bombax, Swietenia maha- 

 goni, the Banyan tree (Ficus religiosa), Liriodendron 

 tulipifera? Platanus orientalis, and our Limes, Oaks, and 

 Yews. The celebrated Taxodium distichon, the Ahuahuete 

 of the Mexicans, (Cupressus disticha Linn., Schubertia 

 disticha Mirbel), at Santa Maria del Tule, in the state of 

 Oaxaca, has not a diameter of 57, as Decandolle says, but of 

 exactly 38 Trench (40-i- English) feet. (Miihlenpfordt, 

 Versuch einer getreuen Schilderung der Republik Mexico, 

 Bd. i. S. 153.) The two fine Ahuahuetes near Chapoltepec, 



