ASCLEPIADE.E 233 



minute paler markings ; 1st internode 4 mm. long ; 2nd to 8th 

 inclusive each about 2-2-5 mm. 



Leaves as in S. variegata, but longer and more acute, and tipped 

 with a cartilaginous point ; 2'5 mm. long. 



GENTIANE^E. 



Benth. et Hook. Gen. PL ii. 799. 



Fruit and Seed. The ovary is superior, syncarpous, con- 

 sisting of two carpels generally uniting by their edges so as to 

 form one cell, with two parietal single or double placentas 

 which are slender or prominent and project into the cavity ; 

 sometimes the margins of the carpels project into the centre 

 of the ovary, forming two cells with axile placentas, as in the 

 tribe Exacese. The ovules are generally numerous in each 

 cavity or on each placenta, and arranged in one or more series, 

 anatropous or amphitropous. The fruit is a thin or hard, 

 rarely a fleshy capsule, dehiscing in most cases by two valves 

 at the sutures, rarely bursting irregularly. Sometimes the 

 whole inner surface is placentiferous. The seed is globose 

 or angled, rarely compressed. The testa is membranous or 

 crustaceous, smooth or rugose, and sometimes produced into 

 a marginal wing all round, or at the base and apex only. 

 Endosperm is copious, surrounding a small and short em- 

 bryo, the radicle of which is superior or points in various 

 directions according to the species. 



Seedlings. The most common form of the cotyledons in 

 this Order is ovate, and they are small like the seeds. In 

 Exacum bicolor (fig. 523), which maybe given as a type, they 

 are roundly ovate, petiolate, 3 mm. long and the same in 

 width. The first pair of leaves is lanceolate-elliptic and tri- 

 nerved, followed by two other pairs which are very much 

 larger, with longer lateral nerves, but otherwise similar. The 

 cotyledons of E. macranthum are broadly and roundly ovate, 

 one-nerved, 3-5 mm. long, and 2-4 mm. wide. The first two 

 pairs of leaves are broadly ovate, obtuse, and trinerved 

 with the lateral ones incurved and joining the midrib close to 



