SUMMARY OP THE CONTENTS. 465 



equal ; whilst we know that certain well-explored districts in Eu- 

 rope have more than three times as many insects as pheenogamous 

 plants .-... - : ;.'::; -i -. .v . . . . 303306 



Considerations on the probable proportion which the number of known 

 phgenogamous plants bears to the entire number existing on the 

 surface of the globe ... .*:"-<:.- ,- 306310 



The different forms of plants successively noticed. Physiognomy of 

 plants treated in a threefold manner ; viz. as to the absolute diver- 

 sity of forms, their local predominance in comparison with the en- 

 tire number of species in different phsenogamous Floras, and their 

 geographical climatic distribution . . . . 312 363 



Greatest extension in height or of the longitudinal axis in arborescent 

 vegetation : examples of 235 to 245 English feet in Pinus lamber- 

 tiana and P. douglasii ; of 266 English feet in P. strobus ; of 298 

 and 300 English feet in Sequoia gigantea and Pinus trigona. All 

 these examples are from the north-west part of the New Continent. 

 Araucaria excelsa of Norfolk Island only attains, according to well- 

 assured measurements, 203 to 223 English feet ; and the Mountain 

 Palm of the Cordilleras, Ceroxylon andicola, 192 English feet 



338340 



These gigantic vegetable forms contrasted with the stem of two inches 

 high of a willow-tree stunted by cold of latitude or of mountain 

 elevation ; and still more remarkably with a phaenogamous plant, 

 Tristicha hypnoides, which, when fully developed in the plains of 

 a tropical country, is only a quarter of an English inch in height 



o41 



Bursting forth of blossoms from the rough bark of the Crescentia 

 cujete, the Gustavia augusta, and the roots of the Cacao tree. The 

 largest flowers, Rafflesia arnoldi. Aristolochia cordata, Magnolia, 

 Helianthus annuus, Victoria regina, Euryale amazonica, &c. 



364365 



The different forms of plants determine the character of the land- 

 scape as dependent on vegetation in different zones. Physiogno- 

 mic classification or division into groups according to external 

 "facies" or aspect, entirely different in its principles from the 

 classification according to the system of natural families. The 

 study of the physiognomy of plants is based principally on what 

 are called th"e vegetative organs, or those on which the preservation 

 of the individual depends ; systematic botany grounds the arrange- 

 ment of natural families on a consideration of the reproductive 

 organs, or those on which the preservation of the species depends 



367371 



On the Structure and Mode of Action of Volcanos in the different Parts 



of the Earth -p. 373 to p. 394. 

 Influence of journeys in distant^ countries on the generalization of 



