560 



BOTANY 



PAfiT II 



Fig. 537. — Pisum sativum. 

 pinnate leaf; r, tendril 

 stipules. 



Stem ; b, 

 , axis of floral shoot ; 



always diplostemonous, monadelphous or more frequently DIADELPHOUS, 



the posterior stamen being 

 free ; the embryo curved 

 (Figs. 536-539). 



The Papilionaceae com- 

 prise both herbs and woody 

 plants ; many are stem- or 

 tendril-climbers. The leaves 

 are generally oddly pinnate. 

 The flowers are usually dis- 

 posed in racemes, more 

 rarely in heads; except in 

 some few genera which 

 leaflets of the approach more nearly the 

 Gaesalpiniaceae (e.g. Toluifera), 

 they are characterised by 

 papilionaceous corollas (Fig. 536). The posterior petal is much enlarged 

 and is termed the STANDARD 

 (vexillum); the two lateral 

 petals represent the wings 

 (alje), while the two an- 

 terior are usually united 

 by their lower margins, and 

 together form the keel 

 (carina). In the bud the 

 wings are enclosed by the 

 standard, the keel by the 

 wings (descending, imbri- 

 cate estivation) ; in the 

 Caesalpiniaceae the aestiva- 

 tion is in exactly the re- 

 verse order (ascending). 

 The stamens in most cases 

 curve upwards. The cohe- 

 sion of the filaments 

 does not generally extend 

 throughout their whole 

 length, so that their upper 

 ends are usually free. 

 Stamens wholly free are 

 found only in a few excep- 

 tional genera, such as 

 Toluifera. The legumes 

 commonly have a parch- 

 ment-like wall ; dry indehiscent fruits rarely occur in this family ; 

 succulent fruits never. 



Fig. 53S. — Coronilla varia (nat. size).— Poisonous. 



