34 THE LYCHEE AND LUNG AN 



the family are known with a high decree of probability. For example 

 we find the species most closely related to the lychee, Litclii 

 chinensis Sonn, and. hence of greatest promise for use as stock, is 

 the Philippine wild lychee, Litchi pkilippinenfiie Radlk. (fig. 2), a 

 large tree reaching a considerable height and growing on the hills 

 and mountains at an altitude of 100-1700 feet. Pscudoncphcliiuti 

 fumatutn (Bl. ) Radlk. is also very closely related and may serve as 

 a useful stock on which to grow the lychee. Considerable experi- 

 mentation along this line has already been done with Euphoria 

 long ana Lam., to which the Philippine form, Euphoria cimrut 

 Radlk. (fig. 3) is closely related. 



Radlkofer places the four fruits in the subfamily Xtplulicuc 

 which he divides into 12 genera with about 78 species. These he 

 classifies under two main divisions. The one, which includes the 

 four species widely cultivated for their edible arils, has indehiscent 

 fruits and is limited to tropical and sub-tropical Asia and the northern 

 islands of the Malayan Archipelago. The other, which includes the 

 Titoki tree of New Zealand, has fruits opening spontaneously at 

 maturity and occurs in Polynesia, Australasia, the southern islands of 

 the Malayan Archipelago and in South Africa. No species of the 

 latter is known to occur on the Asiatic mainland or on the neighbor- 

 ing islands. The first of these groups, with fruits not opening 

 spontaneously at maturity, is divided by Radlkofer into two sub-groups. 

 The one, which includes the lychee and the lungan, has fruits with 

 the arillus free from the seed. The other, which includes the 

 rambutan and the pulassan, has fruits with the arillus adherent to the 

 seed. This subfamily Xcphclieae, with special reference to the four 

 fruits with which we are concerned, can thus be represented as 

 follows: 



1 Fruits indehiscent 



A Fruits with arillus free from the seed 



1 The LYCHEE GROUP comprising the genera Lite hi 

 and Euphoria, and two others, with a total of 15 species 

 (see outline of Lychee Group). 



a Leaflets with lateral veins obsolete. Calyx 1/5 

 cleft; petals none. Fruit muricateand red. Litclii 

 chinensis Sonn. (fig. 44), the lychee of com- 

 merce. 



