ILLUSTRATIONS (21, 22). ORCHTDEJE, CASUARIN.E. 313 



which, in 1813, was only 115, was upwards of 1650 in 1843, 

 and in 1848, the number was estimated at no fewer than 2360. 

 What a treasure of sumptuously flowering and unknown 

 Orchidea? may be inclosed in the interior of Africa wherever 

 there is an abundant supply of water ! Lindley, in his beau- 

 tiful work, On the Genera and Species of Orchideous Plants, 

 1840, counted exactly 1980 species; whilst Klotzsch at the 

 close of the year 1848 counted 3545. 



Whilst the temperate and cold zone possess only terres- 

 trial Orchideae, growing close to the ground, both forms, the 

 terrestrial, as well as the parasitical, growing on the trunks of 

 trees, are indigenous in the beautiful regions of the tropics. To 

 the former class belong the tropical genera Neottia, Cranichis, 

 and most Habenarias. But we have found both these forms 

 as alpine plants on the declivity of the Andes of New Granada 

 and Quito, viz., the parasitical (Epidendrecs) Masdevallia uni- 

 flora (at an elevation of 10,231 feet), Cyrtochilum flexuosum 

 (at 10,103 feet), and Dendrobium aggregatum (at 9485 feet); 

 and the terrestrial forms of Altensteinia paleacea, near Lloa 

 Chiquito, at the foot of the volcano of Pichincha. Claude 

 Gay is of opinion that the Orchideaj supposed to have been 

 found growing on trees in the Island of Juan Fernandez and 

 even at Chiloe, were probably only parasitical Pourretia?, 

 which advance as far south at least as 40°. In New Zealand, the 

 tropical form of Orchidea?, hanging from trees, is still to be 

 seen as far south as 45°. But the Orchideae of Auckland 

 and Campbell Islands (Chiloglottis, Thelymitra, and Acian- 

 thus), grow on level ground in moss. In the animal world 

 there is at least one tropical form that penetrates further 

 south. The Island of Macquarie (lat. 54° 39') has an indige- 

 nous parrot, which lives therefore in a region nearer to the 

 south pole than Dantzig is to the north pole.* 



(22) p. 226—" Form of the Casuarince." 



Acacias, in which the place of the leaves is supplied by 

 phyllodia, Myrtacese (Eucalyptus, Metrosideros, Melaleuca, 

 Leptospermum), and Casuarinse, constitute the sole charac- 

 teristics of the vegetable world of Australia (New Holland) 

 and Tasmania (Van Diemen's Land). Casuarinao with their 



* Compare the section Orchidece in my work, De distrib. geogr^ 

 Plant., pp. 241—247. 



