102 



KNOWLEDGE. 



[May 1, 1896. 



SOME CURIOUS FACTS IN 

 DISTRIBUTION.-II. 



PLANT 



By W. ]5oTTiN(i IIemsley, F.R.S. 



SOi^Il", particulars have already been given of the com- 

 liosition of the vegetation of several of the remote 

 islands in the highest southern insular limits of 

 flowering plants, especially in relation to its general 

 poverty, the absence of shrubby plants, ami the 

 extreme rarity of conspicuous and brightly-coloured flowers. 

 Proceeding northward from Macquarie Island, in the 

 New Zealand region, the climatic conditions arc rapidly 

 less rigorous ; a few degrees of latitude bringing con- 

 siderable change, and a corresponding increase in the 

 variety and character of the plants constituting the 

 vegetation. This is exemplified in Campbell Island, in 

 about .02^ 80' latitude, and still more in the Auckland 

 group, two degrees further north. On the windward side 

 of these islands the vegetation is poor and stunted ; but on 

 the leeward side, and in the sheltered valleys, there is a 

 comparatively rich and varied flora. There arc no very 

 large trees, it is true, but small trees and shrubs abound. 

 The commonest, largest, and most conspicuous tree is 

 Metrosidt'ros Iticida imyrtacere), which attains a height of 

 twenty to forty feet, with a trunk occasionally as much as 

 three feet in diameter. It bears showy crimson flowers, and 

 is a very striking object in the landscape. IhaciiphnUuni, 

 a genus of the heath family, having leaves much like those 

 of a Dnicinm or a small screw-pine, is represented 

 by two arboreous species, totally unlike anything in 

 north temperate regions, and no less striking than 

 the myrtle just mentioned. Vrronicn rUiptira is 

 another small tree inhabiting these islands. Most of 

 our northern species of Veronica are herbs or quite low 

 shrubs ; whereas in the New Zealand region, where 

 the species are much more numerous and varied than in 

 any other part of the world, they are nearly all shrubby, 

 r. fllijitira is the only really arboreous species, sometimes 

 growing as much as thirty feet high, and when covered 

 with its bright blue flowers it is a beautiful sight. 

 It is also still move remarkable that this tree is 

 found in the South American region, growing as far 

 south as Hermite Island (lat. 55° 52), Fuegia, within 

 three latitudinal minutes of Cape Horn. This, I should 

 explain, is a somewhat higher latitude than the remote 

 islands whose vegetation I have described as the highest 

 southern latitudes where flowering plants exist at the 

 present time. I should have added, in remote islands. 

 Among the shrubs of the Auckland Islands flora are 

 many bearing showy berries ; and the herbaceous element 

 includes handsome plants of the aster, orchid, lily, 

 and other families. There are also some very robust 

 and ornamental pink-flowered umbelliferje, allied to our 

 Awielira. Ferns abound, too ; but the characteristic beech- 

 trees and conifers of the New Zealand mainland are wholly 

 wanting. 



Proceeding no farther northward than Stewart Island 

 (47" lat. ), in the extreme south of New Zealand proper, 

 we encounter a subtropical vegetation, in which tree ferns 

 and trees having brilliantly coloured flowers are con- 

 spicuous features. This island, having an area of only six 

 hundred and forty square miles, and altitudes up to three 

 thousand feet, is still imperfectly explored ; yet no fewer 

 than three hundred and eighty species of flowering plants 

 and seventy species of ferns have been discovered within its 

 narrow limits. I must not dwell on the attractions of this 

 rich southern flora, which owes its wealth to a combination 

 of local conditions. Taken as a whole, however, the flora 



of New Zealand is poor in generic forms ; such familiar 

 and wide-spread genera as Hnminriitiis, KpiUihium, Scnecin 

 Vcronicii, and rV/rcc contributing very largely to the total 

 number of species, nearly all of which are endemic or 

 restricted to the islands. The relatively numerous endemic 

 genera are mostly represented by one or few species, and 

 present many interesting phenomena in plant distribution 

 which I cannot attempt to discuss or explain here. I may 

 add that, with the exception of Stewart Island, all the 

 small islands referred to are uninhabited. 



I will now invite the reader to accompany me, in 

 imagination, to some groups of uninhabited islands in the 

 southern part of the Indian Ocean, midway between 

 Macquarie Island to the east and South Oeorgia to the 

 west, but in somewhat lower latitudes, ranging from about 

 forty-seven degrees to fifty-three degrees south. These are 

 the Prince Edward group and Crozets, corresponding in 

 southern latitude to the centre of France in the north ; 

 and Kerguelen and the Macdonald group, corresponding to 

 Cornwall and Nottingham respectively. A glance at the 

 map will teach more than many words the distances these 

 groups of small islands are from each other and from the 

 nearest continents. With the exception of Kerguelen, 

 which has an estimated area of a little more than two 

 thousand square miles, these volcanic islands are all of 

 small extent. Their vegetation is of the scantiest, and its 

 composition is nearly the same throughout, except that 

 Kerguelen has twice as many species as any of the other 

 islands or groups of islands. 



The climate is not very severe and the range of 

 temperature is not great ; yet the nature of the climate 

 is unfavourable to vegetation. In Kerguelen, for example, 

 the thermometer rarely rises to 70° Fahrenheit, and rarely 

 falls more than a few degrees below the freezing point ; 

 but it is almost continuously cold, bleak, and stormy, due to 

 these islands being in the track of the Antarctic currents. 

 Heard Island, in the Macdonald group, is still in a 

 glacial period, with glaciers almost down to high-water 

 mark. This island is about twenty-five miles in length 

 by six in its greatest breadth, with mountains rising 

 to a height of seven thousand feet. Only five species 

 of flowering plants have been collected there, and the 

 same number in the Crozets, with two ferns added ; " 

 fourteen of flowering plants and ferns combined in 

 Marion Island, Prince Fdward group ; and twenty-seven 

 in Kerguelen. Not one is of a woody nature, but fossil 

 wood discovered in Kerguelen affords evidence of the 

 existence of forests at some probably very remote period. 

 Six species out of an aggregate of thirty have not been 

 found elsewhere. One of these, the Kerguelen " cabbage " 

 {Pri)i()len trntisciirJnilica), is specially deserving of notice, 

 both on account of its history and its value as a pot-herb or 

 salad. Captain Cook, although not the discoverer of the 

 island, was the co-discoverer of the cabbage, and took 

 great interest in it in connection with its antiscorbutic 

 properties. Cook was keenly alive to the ravages of scurvy 

 among seamen, especially those engaged on long voyages, 

 away from civilized countries ; and, through the precautions 

 he took, he was very successful in combatting this dreadful 

 disease. 



But in the narrative of the voyage it is William Anderson, 

 surgeon and naturalist to the expedition, who is quoted on 

 the vegetation of Kerguelen, and he says: "Perhaps no 

 place hitherto discovered in either hemisphere on the same 

 parallel of latitude aftbrds so scanty a field for the naturalist 

 as this barren spot." He then goes on to describe, in a 

 general way, the principal plants, including the cabbage, 

 and places the total number of species at about eighteen. 

 He also mentions that they ate the cabbage both raw and 



