AN AUSTRALIAN CITRUS 

 RELATIVE 



NOTES ON THE RUSSEL RIVER LIME 



C. T. White 

 Government Botanist of Queensland, Brisbane, Australia 



IN THE Journal of the Washington 

 Academy of Sciences (V. pp. 569- 

 578) Dr. Walter T. Swingle has 

 separated the Australian plants which 

 had previously been placed under 

 Citrus into a distinct genus which 

 he terms Microcitrus. 



One of the most interesting of these 

 species is M. inodora, the so-called 

 Russell River Lime of which Dr. 

 Swingle (I.e. p. 578) states — 



"So far all attempts to introduce 

 the Russell River Lime into culture 

 have failed and the rapid clearing up 

 of land along the Russell River 

 threatens to exterminate the species 

 altogether. It is hoped that Austra- 

 lian botanists and fruit-growers will 

 not permit this to happen." 

 The United States Department of 

 Agriculture has long been trying to get 

 seeds of this plan for the citrus breeding 

 experiments being conducted under Dr. 

 Swingle, and has written many times to 

 the Australian Department of Agri- 

 culture and Stock in Brisbane to 

 obtain seeds of this citrus fruit as well 

 as of Garcinia Mestoni or Meston's 

 Mangosteen which grows in the same 

 locality and in which Dr. David 

 Fairchild has taken great interest. 

 In January of this year I received 

 instructions to try to collect seeds of 

 both these plants while on a visit to 

 North Queensland in connection with 

 other botanical matters. 



The Russell River and Bellenden 

 Ker Ranges, the area where these 

 plants occur, is situated in the North- 

 east of Queensland. It is also the 



wettest part of Australia, the rainfall 

 averaging over 170 inches per annum. 

 The rainy season lasts from January to 

 April, and during the whole of my stay 

 in the district in early March, it 

 rained continually and the registered 

 rainfall for the previous month (Feb- 

 ruary) was 62 inches. It is a fairly 

 thickly settled country, most of the 

 lower parts being given over to sugar 

 growing. 



Meston's Mangosteen {Garcinia Mes- 

 toni) occurs on the Bellenden Ker 

 Ranges growing from altitudes of 

 about 2,000 feet to 4,700 feet, of 

 "within 300 feet of the summit of the 

 South Peak."i At these altitudes the 

 tree is one of the commonest on the 

 Bellenden Ker Ranges, if not the most 

 abundant tree. It only grows to a 

 height of 20 to 30 feet and is of very 

 graceful appearance. It is heavily 

 foliaged with small, long pointed, 

 bright, glossy, deep green leaves. 

 Unfortunately, no trees bearing ripe 

 fruit were seen, and it is possible that 

 the phenomenally wet weather experi- 

 enced during the past season militated 

 against fruit being set. However, as 

 trees are abundant within 3 miles of 

 Bellenden Ker Railway Station, on the 

 Cairns — Daradgee Railway, no diffi- 

 culty should be experienced in getting 

 ripe seed, as soon as it is available. 



Better success was met with in the 

 case of the Russell River Lime. It 

 was found to be common in the lowland 

 rain forests at the foot of the mountain, 

 and many of the trees were bearing 

 ripe fruits.^ 



* Mestoni — Report by Mr. A. Meston on Expedition to the Bellenden Ker Range — Brisbane 

 1904 (Parliamentary Paper). 



^ Seeds (about 200) were received in June 1922 from Dr. White in good condition, as well as 

 good herbarium specimens with fruits attached. The seeds are now being grown in the Citrus 

 Quarantine Greenhouse of the U. S. Dept. of Agriculture at Bethesda, Md. 



The other three known species of Microcitrus, M. Australis (round lime) M. Australasica 

 (finger lime) and M. Garrowayi (Garroway's lime), all from Australia, are already growing in the 

 collection of the U. S. Dept. of Agriculture. W. T. Swingle 



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