2 



BULLETIN 71, HAWAII EXPERIMENT STATION 



been published in the annual reports and in bulletins (16; 21) 

 of the station. The experimental orchard contains 238 trees, 

 representing 40 different species and varieties (fig. 1), and it has 

 been of value in furnishing data concerning the cultural require- 

 ments and propagation of the trees, and insect and plant-disease 

 control. It has also been a source of propagating material for 

 cooperative experiments in various parts of the Territory. This 

 bulletin has been prepared to meet the demand for general in- 

 formation regarding the culture of citrus fruits under Hawaiian 

 conditions. 



BOTANICAL RELATION 



Botanically the genus Citrus belongs to the family Rutaceae. 

 The term "citrus" was in ancient times applied to a fragrant 

 African wood (3, v. 2, p. 780), but Linnaeus used it as the generic 

 name of the citron and related species. From about a dozen 

 species of citrus many varieties have been developed. 



KINDS OF CITRUS AT THE STATION 



The more important kinds of citrus at the station are the 

 following: 



Sweet oranges (Citrus sinensis) : Hawaiian, Valencia, Medi- 

 terranean Sweet, Navelencia, St. Michael, and Ruby, and Wash- 

 ington Navel, Thompson Navel, and Buckeye Navel ; sour oranges 

 (C. aurantium) : Seville or Bigarade; acid limes (C. aurantifo- 

 lia) : Kusaie, Rangpur, West Indian, and Tahiti ; sour lemons (C. 

 limonia) : Eureka, Villafranca, Lisbon, Sicily, Rough, Ponderosa, 

 and American Wonder; pomelos (C. decumana, C. grandis, C. 

 maxima) : Victoria, Quintal, Gehring, Carter, and Siamese; shad- 

 docks: Bitter, Tantalus, and Pyriform, or Chinese, and Kohala; 

 grapefruits (C. paradisi) (U, p. 156) : Triumph, Duncan, Marsh, 

 Imperial, Foster, Royal, Pernambuco, Tresca, and Woodworth; 

 mandarins (C. nobilis) : Dancy, Satsuma, Willow-leaved, King, 

 Cleopatra, and Clementine; Chinese orange or calamondin (C. 

 mitis) ; citron (C. medico) ; kumquat (C. japonica) ; trifoliate 

 orange (C. trifoliata or Poncirus trifoliata) ; cabuyao (C. hys- 

 trix) ; tangelo (citrus hybrid types) ; and tabog (Chaetospermum 

 glutinosa) . 



The last eight varieties mentioned in the above list have not 

 proven as yet of sufficient importance in the experiments at the 

 Hawaii Station to warrant giving varietal descriptions in this 

 bulletin. 



PROPAGATION 



For more than a century, Hawaiian oranges, limes, lemons, 

 and pomelos 1 were propagated almost entirely from seed in 

 Hawaii. The careful selection of seed from trees of desirable 

 quality gave comparatively good results, but no true varieties 

 could be established without employing vegetative methods of 

 propagation. Inarching, layering, and the rooting of cuttings 

 have not been used to any considerable extent because of certain 



1 The term "pomelos" includes both the grapefruit and shaddock types. 



