LEGUMINOSE^: 323 



together in a long-stalked dense heads, looking like 

 drumsticks. 



MIMOSA PUDICA, L., is the very well-known sensitive 

 plant, the pulvinuses at the base of leaves, pinnae and 

 leaflets being extremely sensitive and motile. 



LEGUMINOSE^: 



The three families, PAPILIONACE.E, C^SALPINE^ 

 and MIMOSE^E, have much in common. Their leaves 

 are usually compound and the leaf-stalk and leaflets 

 commonly fold upwards or downwards at night, moving 

 on their swollen pulvinuses to a much greater extent 

 than members of other families. The flowers are in 

 racemes, heads or spikes, not in a cymose arrange- 

 ments. The pedicel is more or less hollowed and has 

 the parts of the flower on a disc round the top. And 

 above all, the ovary consists of one carpel only, open- 

 ing in fruit, if it does open, as a rule, along two 

 edges, and has many campylotropous seeds, in which 

 there is no endosperm, but an embryo with thick 

 cotyledons that contain much nitrogenous matter 

 (proteids, etc.), besides starch. For these reasons the 

 three families are grouped together into one large 

 family, called because of the fruit the LEGUMINOSE^E. 



They differ in many minor details, but the chief 

 distinction between them, is that in the PAPILIONACE^, 

 the flower is very irregular and the odd uppermost 

 petal is outermost in bud, the aestivation being there- 

 fore called 'descendingly-imbricate'. In the (LESAL- 

 PINE.E, the flower is nearly regular and the odd, upper- 

 most petal is innermost in bud, the aestivation being 



