618 



PART III. THE CLASSIFICATION OF PLANTS. 



Various species are cultivated as ornamental plants. In Cotiuus many of the 

 flowers are abortive, and the hairy peduncles become much elongated. The 

 genus Ehus includes the Sumachs; there are no 

 antipetalous stamens : P. Coriaria (Southern 

 Europe) is used in tanning. Pistacia vera, in 

 Southern Europe, bears edible seeds (Pistachio- 

 kernels) ; in the flowers of this genus the petals, 

 and in the $ flower the stamens which are 

 opposite to them, are suppressed. 



FIG. 420. Floral diagram of 

 Rhus. 



Cohort III. Celastrales. Flowers 

 regular, frequently actinomorphic, 4-5- 

 merous ; only one whorl of stamens 

 which either alternates with or is opposite to the petals, is usually 

 present : disc usually within, sometimes external to, the androe- 

 cium : ovules usually erect : the seed nearly always contains 

 endosperm. Trees or shrubs. 



Order 1. CELASTRACE^E. Formula, Kn, Cn, Ar\, G (n) or less, 

 n 4 or 5 : sepals imbricate: stamens and carpels inserted on a 

 flattened disc : stamens alternate with the petals : usually two ovules 

 in each loculus of the ovary : leaves scattered, entire, stipulate. 



In the genus Euonymus, the Spindle-tree, the loculicidal capsule contains 

 seeds invested by an orange -coloured arillode (p. 459); E. europcea occurs both 

 cultivated and wild. 



Order 2. STAPHYLEACE.S!. Flowers pentamerous : stamens alter- 

 nate with the petals: disc intrastaminal : ovary generally trimerous 

 and trilocular ; ovules numerous : leaves decussate, pinnate, stipu- 

 late: seed with small endosperm. 



Staphylea pinnata is grown in gardens. 



Order 3. RHAMNACEJS. Formula, Kn, Cn, \ An, G^; n=4> 

 or 5 : calyx usually gamosepalous, val- 

 vate : petals usually small and often 

 hood-shaped (Fig. 421 c), enclosing the 

 stamens which are opposite to them : 

 flowers sometimes diclinous : usually a 

 single ovule in each loculus of the ovary 

 which is invested by a disc : leaves 

 usually scattered, entire, stipulate : fruit 

 or a capsule. 



Pia. 421.-Flow 

 Fmngula (mag.) : fe sepals con- 

 nate at the base into a tube (d) ; 

 c hood-Rhaped petals enclosing 

 the stamens (a). 



p hamnng ea thartica, the Buckthorn, has op- 

 P osite leaves and Hory twigs : the berries of 

 R. infectoria, in Southern Europe, yield a green 



