REPORT ON TFIE BOTANY OF THE SOUTH-EASTERN MOLUCCAS. 103 



rock which everywhere appears in the ravines and brooks is a coralline limestone, in some 

 places soft and pliable, in others so hard and crystalline as to resemble our mountain lime- 

 stone. The small islands which surround the central mass are very numerous . . . and 

 all are covered with a dense and very lofty forest." Here is another short extract, begin- 

 ning at p. 294, in which Wallace summarises his knowledge and impressions of the vegeta- 

 tion : — " Persons who have formed the usual ideas of the vegetation of the tropics — who 

 picture to themselves the abundance and brilliancy of the flowers, and the magnificent 

 appearance of hundreds of forest trees covered with masses of coloured blossom, will be 

 surprised to learn, that though vegetation in Aru is highly luxuriant and varied, and 

 would afford abundance of fine and curious plants to adorn our hothouses, yet bright and 

 showy flowers are, as a general rule, altogether absent, or so very scarce as to produce no 

 effect whatever on the general scenery. To give particulars : I have visited five distinct 

 localities in the islands, I have wandered daily in the forests, and have passed along 

 upwards of a hundred miles of coast and river during a period of six months, much of it 

 very fine weather, and till just as I was about to leave, I never saw a single plant of 

 striking beauty, hardly a shrub equal to a hawthorn, or a climber equal to a honeysuckle ! 

 It cannot be said that the flowering season had not arrived, for I saw many herbs, shrubs, 

 and forest trees in flower, but all had blossoms of a green or greenish-white tint, not 

 superior to our lime-trees. Here and there on the river banks and coasts are a few Convol- 

 vulaceae, not equal to our garden Iponiceas, and in the deepest shades of the forests some 

 fine scarlet and purple Zingiberacese, but so few and scattered as to be nothing amid the 

 mass of green and flowerless vegetation. Yet the noble Cycadacese and screw-pines, thirty 

 or forty feet high, the elegant tree-ferns, the lofty palms, and the variety of beautiful and 

 curious plants which everywhere meet the eye, attest the warmth and moisture of the 

 tropics and the fertility of the soil. It is true that Aru seemed to me exceptionally poor 

 in flowers, but this is only an exaggeration of a general tropical feature ; for my whole 

 experience in the equatorial regions of the west and east has convinced me that in the most 

 luxuriant parts of the tropics, flowers are less abundant, and on the average less showy, 

 and are far less effective in adding colour to the landscape than in temperate climates. I 

 have never seen in the tropics such brilliant masses of colour as even England can show in 

 her furze-clad commons, her heathery mountain-sides, her glades of wild hyacinths, her 

 fields of poppies, her meadows of buttercups and orchises — carpets of yellow, purple, azure- 

 blue, and fiery crimson, which the tropics can rarely exhibit." 



With regard to the former physical condition of the Arrou group, Wallace, after review- 

 ing the geological evidence and the distribution of the plants and animals, but more 

 especially the latter, comes to the conclusion that at no very distant epoch these islands 

 formed a part of New Guinea, and became separated by the subsidence of the great plain 

 which formerly connected them with it. 



The stay of the Challenger Expedition at the Arrou and Ki islands little exceeded a 



