DICOTYLEDONS 209 



which also arise from the apex of the axis, which here 

 forms the placenta (Fig. 49, H). The lower Centro- 

 spermse have small, inconspicuous flowers which are 

 principally self-fertilized; but some of the higher ones, 

 e.g. the pink family, often exhibit very showy flowers 

 which depend upon insect aid. In these more special- 

 ized types the calyx is usually cup-shaped or tubular 

 instead of being composed of completely separate sepals 

 (Fig. 49, G). Somewhat higher is a second order 

 (Cruciflorse), including the Cruciferse (mustard family) 

 and poppies (Papaveracese). In these the carpels are 

 usually of definite number and united into a compound 

 pistil. The former family is one of the most clearly 

 defined of all the Angiosperms, having always the same 

 number of parts in the flower, i.e. four sepals and petals, 

 six stamens, and two carpels (Fig. 51, A, B). The 

 poppies are more variable in the number of parts in the 

 flower, and must be considered as a more generalized 

 family than the Cruciferse, and more nearly related to 

 the Polycarpicse. 



The sundews and pitcher-plants (Fig. 58) represent 

 the order Cistiflorse, and are distinguished by perfectly 

 symmetrical flowers, but are of most interest on account 

 of their extraordinarily modified leaves, which form very 

 efficient insect-traps. The violets, which also belong to 

 the Cistiflorse, are characterized by their showy, strongly 

 zygomorphic flowers. 



Under the name Eucyclse have been included a large 

 number of families grouped into four orders, charac- 

 terized by usually symmetrical flowers whose parts are 

 in fives. Among these may be mentioned the vines 

 (Vitacese), maples (Aceracese), geraniums (Gerania- 



