RUTACEiE 489 



japonica, the Round or Marumi kumquat. The former is 

 athornless shrub or small tree with oval fruit, the latter a 

 thorny shrub with globose fruit. F. crassifolia is the Meiwa 

 kumquat, and F. hindsii, the Hongkong wild kumquat. 

 The latter is considered by Swingle to be the wild stem form 

 of our Citrus species. 



Uses. — The kumquats are shrubs grown as -ornamentals, 

 and also for their fruit, which is eaten raw and entire. 



PONCmUS, (TrifoUate Orange) 



Description. — The trifoliate orange is a low tree, seldom 

 over 15 feet high; the older branches are thorny, the thorns 

 being i to ij^ inches long, and flattened at the base; the 

 characteristic deciduous trifoliate leaves are composed of 

 thin, elliptical, crenate or dentate leaflets; t\iQ flowers usually 

 appear before the leaves, singly or in pairs in the leaf axils; 

 the five sepals are greenish yellow in color, and pointed at 

 the tip; the corolla is white; the fruit has a light orange color, 

 is rough, and covered with short hairs; it is of no com- 

 mercial value; the numerous seeds differ from those of other 

 allies in being oval, rounded at one end and blunt-pointed 

 at the other. The pulp is acid, bitter, and gummy. 



A Hardy Orange. — The trifoliate orange is a native of 

 China and Japan. It is the hardiest of our citrus species, 

 and for that reason has been used in crosses with less hardy, 

 but more desirable species, in the hope that hybrid forms 

 would be secured which would combine hardiness and de- 

 sirable fruit characters. Hybrids of trifoliate and sweet 

 oranges are known as citranges. Varieties of citranges are 

 Colman, Morton, Rusk, Rustic, and Savage. 



References 



BiERMANN, M.: On the Structure and Development of the Fruit of Citrus 

 Vulgaris. Arch. Pharm., 235: 19-28, 1897. 



