XIV 



LIST OF ILLUSTRATIONS 



FIG. PAGE 



133. Top of flower-slope below weathering crag in southern Baffin Island 408 



134. Spitsbergen flower-slope dominated by Alpine Arnica . . . 408 



135. High in the mountains near the margin of the ice-sheet in southern 



Greenland . . . . . . . . . .411 



136. Upland scrub of Dwarf Birch and silky-leafed Willows constituting 



an altitudinal climax abo\e tree-limit in northern Norway . 411 



137. High-alpine vegetation and flowering . . . . . .412 



138. Alpine puna-like formation near mountain summit in Colombia . 414 



139. Crustaceous and foliose Lichens on rocks near shore, Goudier Islet, 



Antarctica .......... 416 



140. Luxuriant growth of Mosses, broken chiefly by rocks bearing Lichens, 



extending up snow-melt gully in area frequented by Penguins, 

 Deception Island, Antarctica ....... 418 



141. Profile diagram of primary mixed tropical rain forest, Moraballi 



Creek, British Guiana ........ 426 



142. Profile diagram of climax evergreen forest in Trinidad, British West 



Indies ........... 426 



143. Tropical rain forest in the Philippine Islands .... 427 



144. Another scene of tropical rain forest in the Philippines . . 429 



145. Base of tree-trunk showing exaggeratedly buttressed roots in tropical 



rain forest .......... 429 



146. An epiphytic Fern which has small humus-gathering leaves and 



larger photosynthetic ones that also produce spores . . . 433 



147. An epiphytic Bromeliad with a mass of fibrous roots investing the 



branch of the ' host ' tree ....... 433 



148. Roots of Strangling Fig on a large tree-trunk .... 435 



149. An old specimen of Strangling Fig in which the roots serve as trunks, 



the original ' host ' having disappeared ..... 436 



150. Flower and buds oi Rafflesia monillana, a true parasite on the roots of 



a Cissiis vine .......... 437 



151. A tropical hemiparasitic Mistletoe, Viscum orientale, the root of 



which forms a single haustorium ...... 438 



152. Palm-savanna in southern Florida ...... 445 



153. Savanna in Australia under rainfall of 25-75 cm. annually . . 446 



154. Semi-desert ' bush-land ' in Australia ...... 448 



155. Arizona near-desert scene showing the giant Saguaro (or Sahuaro) 



Cactus and bushy Ocotillo . . . . . . .451 



156. Areas of desert in central Iraq ....... 453 



157. A typical Mangrove plant, Rhizophora candelaria, forming a char- 



acteristic marginal ' mangrove ' and showing prominent prop-roots 

 below 455 



158. Interior of Philippine mangrove-swamp forest at low tide . . 455 



159. A Screw-pine and a subtropical estuarine salt-marsh . . . 459 



160. Coconut Palms along a tropical sea-coast . . . . .461 



161. Two-storied montane rain forest at an altitude of 740 inetres in the 



Philippine Islands ......... 468 



162. Epiphytes on trunk of tree near upper limit of montane rain forest in 



the Philippine Islands ........ 469 



163. Mossy elfin forest near summit of mountain, Philippine Islands . 470 



164. Vascular plants floating freely on fresh water . . . .484-5 



165. Diagrammatic representation of the plankton in a Wisconsin lake 



during May to October ........ 486 



166. Diagram indicating distribution in a European lake of a cyanophycean 



{Glosotrichia echinulata), which is rendered buoyant by included 

 gas-vacuoles .......... 487 



167. Diagrammatic representation of a typical lake-marginal profile . 493 



168. Diagram of cross-section through a ' highmoor ' bog that has arisen 



from a small lake ......... 501 



169. Leaves of Sacred Lotus projecting out of the water, and Pistia stratiotes 



floating on the water, in the Philippine Islands . . . 504 



