102 



IX. SOUTH AMERICA. 



One member of this Commission (Tryon, 

 1911, pp. 15, 19) had already drawn attention in 

 Queensland to the presence of two serious enemies 

 of Prickly-pear in Argentina, viz., the " gan- 

 grena blanca" due to a fungus parasite, and the 

 " agusaaatniento " an insect borer. Moreover, 

 while making inquiry in Italy, he met in Rome 

 Dr. C. Spegazzini, the well-known botanist of La 

 Plata, who has written extensively on the Cac- 

 taeeaj and fungi of the Argentine Republic. Dr. 

 Spegazzini stated that there was a rich cactus 

 flora in that country. In regard to the possibility 

 of using insects or disease in destroying prickly- 

 pear, he thought that Argentina should be 

 searched for such enemies, and called attention 

 to some that he had met with there. Amongst 

 the insects were the following: — (1) A Coccus or 

 Fseudococcus related to C. cacti and which was 

 common on indigenous species of Opuntia, but 

 apparently not fatal to any of them, though it 

 appeared to be capable of checking the plant's 

 growth; (2) a Diaspid scale insect which he 

 regarded as a serious enemy of Cereus, but not 

 so injurious to Opuntias; and (3) the caterpillar 

 of a lepidopteron, which burrowed into the stem 

 joints and with which there was associated the 

 larva of a fly. In regard to diseases, he referred 

 to a serious malady caused by a fungus, 

 Sclerotinia opuntiarum, which was capable of 

 attacking all kinds of Cactaeeffi, but especially 

 Opuntia decumana (ficus-indica) and Pilocereus 

 formosissimus. The stem joints, roots, and fruit 

 becoming infected during the winter months. 



In view of such information, it was deemed 

 advisable to carry out investigations in South 

 America. In order to economise time, it was 

 decided that this should be carried out by one 

 member of the Commission, while the other was 

 engaged in studying the Cactacea and their 

 enemies in the various West Indian islands. 



COLOMBIA. 



On the voyage from Jamaica to Barbados, 

 the steamer called at Cartagena and Puerto 

 Colombia, two ports on the North coast of the 

 Republic of Colombia, affording a brief oppor- 

 tunity to inspect the CaetaccEe. Between Puerto 

 Colombia (Savanilla) and Barranquilla one may 

 see various kinds of Cereus, including C. ptero- 

 gonus, Lem., and, in addition, a low-growing 

 Opuntia closely resembling the Jamaican 0. tuna 

 m the general characters of the plant, par- 

 ticularly the spines. This latter species was 

 especially abundant in the low sandy country 

 around the mouth of the Magdalena River. 



SOUTH BRAZIL. 



A journey was made from Barbadoes to Rio 

 de Janeiro, at whose Botanical Gardens Dr. J 

 C. Willis (the Director) and Dr. A. Loefgren 

 were interviewed. These botanists suggested 

 that that portion of the State of Bahia which is 

 near the valley of the San Francisco River should 

 be visited, as that region is very dry and supports 

 an abundant cactus flora, one of the species 

 inammna, Schum. (they believed), eloselv 

 resembling the pest pear of Queensland. Al- 

 though certain other indigenous Brazilian species 



such as 0. monacantha and 0. nic/ricaiis* occur 

 naturalised in Eastern Australia, yet they are 

 found only in scattered situations in the moister 

 parts of South-Eastern Brazil which are not 

 readily accessible. The adjacent States of Ceara 

 and Pernambuco also have dry tracts with a 

 cactus flora similar to Bahia. 



It was decided to visit Bahia on the return 

 journey from Chili and Argentina and to omit 

 visiting certain other countries — e.g., Peru, 

 Northern Chili, and Bolivia, on account of the 

 amount of time which would be necessary to 

 make even a casual examination of the Prickly- 

 pear of those regions. 



ARGENTINA AND CHILI. 



After arrival at Buenos Aires a visit was 

 paid to the Botanical Gardens at Palermo and 

 also to the neighbouring city of La Plata, where 

 much assistance was rendered by Dr. C. Spegaz- 

 zini, whom the Commission had met in Rome, and 

 who, as already mentioned, has given considerable 

 attention to the fungi and Cactaceaj of Argentina. 

 The collection of Opuntias at La Plata was 

 examined and certain enemies were pointed out 

 by this botanist. From him it was ascertained 

 that though species of Opuntia occurred in the 

 moist wooded regions near the Paraguayan and 

 Brazilian frontiers, yet the chief Prickly-pear 

 region was in the West and North- West of the 

 republic, along the foothills of the Cordillera, 

 particularly in the States of Mendoza, Salta, 

 Jujuy, Tucuman, Catamarca, Santiago d'Estero, 

 La Rioja, and Cordoba, where arid conditions 

 prevailed. As Mendoza is situated on the trans- 

 continental railway line from Buenos Aires to 

 Valparaiso, it was decided to examine the region 

 surrounding that city on the return journey from 

 Chili. 



While crossing the Andes, it was noticed that 

 abundant low-growing Prickly-pears (0. sul- 

 furea, Gillies) and Cereus (Echinopsis letican- 

 tha, Walp. ; Pilocereus rhodacanthus, S.D. ; Cereus 

 candicans, Gillies ; C strigosns, S.D. ; and others) 

 were present in the lower altitudes, but that 

 they all disappeared from the flora after an eleva- 

 tion of about 6,000 feet had been reached, C. 

 strigosus, a plant of about 4-6 feet high, extend- 

 ing to a somewhat higher altitude than the others. 

 On the Chilian side, after the 6,000-feet level has 

 been passed on the downward journey, one meets 

 with great numbers of a tall species of Cereus, 

 presumably C. chilensis, CoUa, whose range 

 extends to the coast, this plant growing at 

 Valparaiso. 0. ficus-indica may be seen fairly 

 commonly in parts of Chili such as Los Andes, 

 Llaillai, Santiago (de Chili), and Valparaiso, 

 where it is grown for its fruit just as in Southern 

 Europe. 



A visit was paid to Dr. Soehrens, Director of 

 the Botanical Gardens at Santiago, where a small 

 collection of Cactaceas is housed. Amongst them 



* Dr. Loefgren stated that O. nigricans is met'with as 

 a rather rare plant near Itabira de Matto Dentro in the 

 State of Minas Gereas ; and that 0. monacantha was to be 

 found as scattered plants in wooded country in the States 

 of San Paulo, Minas Gereas and Rio Grand de Sul. 0. 

 brasihensis was also to be found in the latter localities. 

 Schumann (1899, p. 728) thought that the home of 0. 

 nigricans was probably Mexico. 



