112 



ilaiden reports its presence at Dutton Bay, in 

 Koutli Australia. We doubt the correctness of 

 the identification, and prefer to use the name 

 " Uayndah pear " or " spiny pest pear " for it. 

 It isCcrfaiiily related to 0. dillonii, but differs 

 from it notably in the character of its spines and 

 flowers. We have seen the latter species growing 

 naturalised in India, Ceylon, and Canary Islands, 

 and the Mediterranean littoral, and indigenously 

 in the West Indies. 



0. inermis, DC, var. — This is the common 

 pest pear of Queensland and New South Wales, 

 and has been referred to under various names, 

 amongst them being 0. tuna, 0. vulgaris, and 

 O. stricta. 



Prickly-pear is mentioned as being one of 

 the plants taken on board the first fleet when it 

 touched at Rio de Janeiro.* The plant intro- 

 duced by Governor Phillip in 1788 was referred 

 to in one account as the cochineal fig. Cactus 

 cocMnilifer, L.-f The early cultivation of the 

 plant received notice from Mr. J. V. Chataway 

 (1898, p. 136). It has been assumed that it was 

 the pest pear which was then introduced. Is it 

 not possible that 0. monacantha, which is a native 

 of South-eastern Brazil, and perhaps 0. nigri- 

 oans, whose home is some distance inland from 

 Rio de Janeiro, may have been included? 



The pest pear was taken to Scone about 1839 

 (Maiden, 1912 b, p. 713), and from that centre 

 specimens were conveyed to Warwick, whence it 

 has spread over great areas of Queensland and 

 Northern New South Wales. 



It has been referred to in the account of our 

 investigations in the West Indies, its home being 

 probably Cuba (and Haiti) and perhaps the 

 Florida Keys. A closely allied and perhaps iden- 

 tical species described by Dr. Griffiths under the 

 name 0, bentonii, is indigenous to Louisiana and 

 adjacent portions of the United States of 

 America. 



Opuntia, sp. — It is under this designation 

 that Mr. Maiden has described the " Westwood 

 pear " found in the neighbourhood of Westwood 

 and Rockhampton. 



It is related to the " Cardona " (0. strepta- 

 cantha) of Mexico. Dr. Griffiths, of Washington, 

 U.S.A., informed the Commission that it was 

 closely allied to 0. megacantJm and 0. chavena. 

 The common naturalised species in the Hawaiian 

 Islands has been already referred to as resemb- 

 ling it. 



Nopalea cochinelifera. — Amongst the species 

 whose presence has not so far been recorded in 

 scientific literature is Nopalea cochinelifera, L., 

 an unarmed tree-pear found at Gayndah and 

 Emerald. It is not a pest. 



Another species apparently uncommon, and 

 known locally in the Rockhampton district as the 

 ' Yellow-fruiting Mexican pear," resembles cer- 

 tain spiny forms such as 0. amyclwa and other 

 members of the 0. ficus-indica group. 



Mr. Froggatt (1912, p. 943) has collected 

 evidence regarding the action of birds as distri- 

 butors of prickly-pear seeds in their droppings. 

 It is stated that the emu feed s on the fruit and 



, ^oQ*i ooS l^^f; " 7^^ Coming of the British to Australia," 

 1788-1829." (London, 1906, p. 9.) 



• X t. ^f.- Ma.iden (1898, p. 980) also has referred to the 

 introduction. 



assists in scattering seeds of the pest, seedlings 

 being obtained from the droppings of that bird. 

 Other fruit-eating birds, not named by him, are 

 said to act in the same way, as also do horses and 

 cattle. 



Utilisation iit. the Industries. 



Professor Dunstan, of the Imperial Institute, 

 London, as well as Mr. E. Harris, Editor of the 

 Agricultural Gazette, New South Wales (1909, 

 p. 245), referred to a statement in the Press that 

 a Brisbane chemist, who had so far remained 

 anonymous, had discovered commercial possibili- 

 ties in the prickly-pear, the production of spirits, 

 feed-cake, strawboard, and sugar being men- 

 tioned. 



The question of producing feed-cake, alcohol, 

 and sugar from Opuntias has been referred to 

 elsewhere in this report. 



Mr. J. C. Briinnich, the Agricultural 

 Chemist of our State, examined prickly-pear 

 with a view to testing the possibility of procur- 

 ing alcohol, and found that very little was obtain- 

 able (1909, p. .3). Some has been made in a 

 Sydney laboratory (Harris, 1909, p. 246). 



Mr. F. H. Campbell has recently examined 

 the products derived from the destructive distil- 

 lation of prickly-pear, his results being published 

 in the last report of the Australasian Associa- 

 tion for the Advancement of Science (1914). He 

 examined the species 0. monacantha and 0. iner- 

 mis. From the former he obtained a faintly 

 luminous gas which was found to be composed 

 mainly of hydrogen, carbon monoxide, and nitro- 

 gen, with smaller quantities of methane, carbon 

 dioxide, and oxygen. The liquid distillate con- 

 sisted of acetic acid and tarry substances. 

 Ammonia, pyridine, and a trace of phenol were 

 found, but the amount of methyl alcohol was 

 shown to be negligible. The crude tar constituted 

 about 1 per cent, of the original green material. 

 It had very little tenacity. The charcoal obtained 

 was clean and porous, and amounted to about 4 

 per cent, of the green material examined. The 

 results from 0. inermis were similar. The quan- 

 tity of acetic acid worked out at 345 lb. per ton 

 of green stuil, crude tar 22 lb., charcoal 89-6 lb., 

 the remainder being composed of water and small 

 amounts of pyridine and ammonia.^ 



The ash of 0. monacantha was examined 

 and was found to be readily fusible, thus indicat- 

 ing a high alkalinity. There was 36-67 per cent, 

 of lime and traces of copper were present. 



Mr. Campbell concludes by stating that if 

 crude calcium acetate be valued at 8d. per lb., 

 refined pyridine at 4s. 6d. per lb., and charcoal 

 at 20s. per ton, then the value of products per 

 ton of green plant is approximately 8s., which 

 amount he believes would probably not cover the 

 cost of clearing the land. The value of the gas 

 produced was not taken into account in making 

 the estimate, as it would be most profitably used 

 as fuel for heating the retort. 



Mr. Maiden (1913 a, p. 55) believes that the 

 utilisation of pear as a producer of alcohol, fibre, 

 &c., is not likely to be a commercial success, but 

 may help to reduce the cost of clearing pear- 

 infested land. This opinion is already held by 

 many in our own State. 



