604 



BOTANY 



PART n 



species have trifoliate leaves and the articulation at the base of the lamina 



that the apparently simple leaves correspond to imparipinnate leaves, of 



only the terminal leaflet is developed. The thorns at the 



base of the leaf are derived by modification of the first 



leaves of the axillary bud. Citrus is originally an East 



Asiatic genus ; a number of species inhabit the warmer 



valleys of the Himalayas. All the important cultivated 



forms have been obtained from the Chinese. Citrus 



decumana, the Shaddock, is tropical ; C. medica is the 



form which was known to the Greeks in the expeditions 



of Alexander as the Median apple. It is now widely 



spread and has a number of varieties of which Citrus 



{■medica) Limonum is the Lemon. This tree was introduced 



into the Mediterranean region in the third or fourth 



century. Cifriis {medica) Bajoura has thick-skinned fruits 



from which citron is obtained. Citrus Aurantium occurs 



in two distinct forms, C. {Aurantium) vulgaris and C. 



{Aurantium) sinensis. The latter is a variety of the 



Bitter Orange tree of apparently Chinese origin, and 



already comes more or less true to seed (cf Apogamy, 



shows 

 which 



Fio 010.— Floral diagram uf/'o??/y(i7a myrlifolia. (After Bichler. ) 



4 



Fig. 611. — /'o/i/</fi?a Senega. A, Flowei ; a, small; b, large sopal.s (■, \/ i 



keel; e, lateral sepals; </, androecium. /i, androecium ; h, aiitliers Pia. 612.— Polygula Senega. 

 (niagiiilied). (After Uekg and Schmidt.) official. ^ ^^^^ size.) Official. 



p. 283). The name Orange, which is introduced into many languages and is 

 derived from the Sanscrit word Nagarunga, points lo the ancient cultivation 

 of the plant in India. The name was first applied to the Bitter-fruited Orange, 

 which found its way west much earlier that the sweet variety, and was sub- 



