Sept. 4, 1884] 



NA TURE 



437 



organ. In that from Cresswell Crags, as well as those from La 

 Madelaine, the jaw is heavier than in the recent specimen. 

 Brosely, August 29 W. W. Watts 



"The Ores of Leadville" 



My attention has lately been drawn to a review in Nature 

 for April 17 of a work on " The Ores of Leadville and their 

 Mode of Occurrence," by Mr. L. D. Ricketts, from which one 

 would be led to suppose that all the facts mentioned were due to 

 original investigation on the part of the author. Your reviewer 

 does not state that which is acknowledged by the author himself, 

 namely, that much of his information was obtained from the 

 Report of the U.S. Geological Survey by Mr. S. F. Emmons, 

 contained in the Second Annual Report, published a year 

 previously. 



A large atlas has lately been issued also by the U.S. Geologi- 

 cal Survey completely illustrating the Leadville ore deposits, and 

 an exhaustive monograph to accompany it is now in the printers' 

 hands. I speak from an intimate knowledge of the subject, 

 having taken part in the work, and should be much obliged by 

 your inserting this correction without delay. 



Ernest Jacob, 

 Late Assistant Geologist U. S.G. S. 



2, Beachfield Terrace, Penzance 



AUSTRALIAN ORCHIDS 

 "THE seventh and last part of vol. i. of Fitzgerald's 

 *■ " Australian Orchids," and the first part of vol. ii. 

 have lately reached us. The testimony we bore to the 

 value and merits of this work in our notice of part 5, 

 vol. i. (Nature, vol. xxii. p. 53) we can now repeat, and 

 with emphasis, as we can base it on an examination of all 

 the parts at present issued. 



Mr. Fitzgerald is an ardent admirer and disciple of 

 Darwin — indeed what true lover of orchids is not ? — and 

 his work is dedicated to his memory " as a token of the 

 veneration in which he holds that great naturalist and 

 fearless expounder of science." The synopsis shows that 

 twenty-eight genera and 104 species are illustrated and 

 described in vol. i., each part containing ten folio litho- 

 graphic plates. The drawings and dissections leave 

 nothing to be desired in point of fulness, completeness, 

 and accuracy, the latter especially being far more 

 numerous and varied than in any similar work we are 

 acquainted with. There is one point on which those who 

 are responsible for the nomenclature of Australian orchids 

 are entitled to decided praise. AH but one of the genera 

 and 90 out of the 104 species in vol. i. bear really 

 descriptive names, instead of being christened after 

 " enterprising," or rather advertising, nurserymen or 

 vanity-stricken cultivators, which is unfortunately the fate 

 of most of the new orchids introduced into England. A 

 large proportion of the orchids as yet described in this 

 work are natives of New South Wales, but a few are con- 

 tributed by Western Australia, Queensland, South Aus- 

 tralia, and Tasmania. The enormous importance of in- 

 sects to the maintenance of orchids is shown by the fact 

 that, out of 104 species described in vol. i., ten only are 

 self-fertilising. But the curious point is noted by the 

 author that " self-fertilising species always produce a far 

 greater proportion of seed." The difficulty with which 

 some genera undergo fertilisation is illustrated by an in- 

 stance given where a splendid plant of Dendrobium Hillii 

 in the Sydney Botanic Gardens, freely open to insects, 

 did not produce a single seed, though covered with about 

 40,000 flowers on 190 spikes ! In another case men- 

 tioned by the author he found a small caterpillar on a 

 flower of Dendrobium speciosum, which had partly eaten 

 an adjoining flower. He marked the latter, and the 

 flower so marked was the only one on the entire plant 

 which produced seed. There is strong evidence that 

 many species are dependent, not simply on insects, but on 

 some particular, perhaps local, insect for fertilisation. 

 Sareochilus pa>~viflorus often produces seed capsules in 



its native habitat, the Blue Mountains ; if removed to 

 Sydney, it flowers well, but does not produce seed unless 

 artificially fertilised. One question discussed by the 

 author is the fertility of hybrid orchids. We believe that 

 this question has been settled in English plant-houses, 

 where hybrids have been proved to be fertile in the case 

 of one genus (Cypripedium) at all events. This result is 

 what Mr. Fitzgerald anticipates, on account of the facility 

 with which species of the same genus may be cross- 

 fertilised, however far apparently they may be removed 

 from one another. As he says, " a repugnance to inter- 

 mixture does not exist in this family as it does in others." 



While terrestrial orchids are very numerous in Australia, 

 epiphytal orchids are comparatively rare. The latter are 

 more ordinarily denizens of the hot and moist forests of 

 tropical or sub-tropical regions. Thus not more than 

 one-fifth of the species illustrated in Mr. Fitzgerald's work 

 are epiphytal, and these belong almost entirely to the 

 genera Sarcochilus and Dendrobium — the latter a genus 

 of which there are probably two or three hundred species, 

 mostly natives of Indo-Chinese regions, cultivated in this 

 country. On the other hand, the author says : — " The 

 centre of the terrestrial " (orchids) " may, I think, be 

 placed in Sydney, where, within the radius of a mile, I 

 have obtained 62 species of orchids, 57 of which were 

 terrestrial — a number that could not, I believe, be equalled 

 in any part of the world within a similar area." 



The plates are accompanied by full descriptions giving 

 curious and interesting details as to the methods of insect- 

 fertilisation, and describing localities, surroundings, con- 

 ditions of growth, &c. Notwithstanding the help derived 

 from this source, Australian orchids have not, with some 

 few exceptions, proved readily amenable to cultivation in 

 this country. While it is comparatively easy to reproduce 

 climates resembling those of the damp, shady, and hot 

 valleys of the Amazon or of Burmah, or of the moist, 

 cloud-covered, and cool slopes of the Andes or the Hima- 

 layas, it is very difficult to reproduce the dry, hot, and 

 sunny conditions favourable to most of the terrestrial 

 orchids of Australia. We shall therefore probably con- 

 tinue to know these for some time at least mainly from 

 Mr. Fitzgerald's book. We doubt whether, excellent and 

 obviously faithful as his drawings are, and carefully as 

 they are coloured, the use of toned paper is judicious. It 

 imparts a muddiness to the tints, as, for example, in the 

 drawing of the beautiful Dendrobes, Phatenopsis, and 

 Superbiens, part 7, vol. i., and part 1, vol. ii., where neither 

 foliage nor flower have the clear bright colours natural 

 to them. 



Before concluding this notice of a work which de- 

 votes much attention to the curious and interesting 

 study of orchid fertilisation, we might refer for a 

 moment to the patience, care, and intelligence with 

 which the raising of hybrid orchids is being prose- 

 cuted in this country, especially in the nursery of Messrs. 

 James Yeitch and Sons. In one genus, that of Cypri- 

 pedium, the hybrids bids fair already to outnumber the 

 known natural species, as well as to rival them in interest 

 and beauty. The closely allied genera Cattleya and 

 Laslia, which are distinguished only by the number of 

 their pollen masses, have proved susceptible of cross- 

 fertilisation, and have produced several intermediate 

 hybrids of great beauty. It may well be said that patience 

 is necessary^ for this work, for Cattleya exoniensis, the 

 offspring of Cattleya Mosshe and Lalia purpurata, did 

 not flower until seventeen years after the seed had ger- 

 minated. Even now it is only propagated by subdivision. 

 The union of the genera Calanthe and Limatodes was 

 more speedily fruitful : and the beautiful Calanthe 

 Veitcliii, especially valuable horticulturally, from its 

 winter-flowering habit, is known in most gardens. 



Few who have devoted themselves to the study or to 

 the cultivation of orchids have failed to become greatly 

 interested in this remarkable family. Their singular 



