8o MALE AND FEMALE. 



only with stamens. In vain do you hunt on the same stem 

 for their companions, the female flowers. You will find them 

 only upon other stems, distinct from those which bear the 

 male flowers. The Dog Mercury, then, is a plant whose two 

 sexes are lodged in two different houses, o/W is, in fact, a 

 dioecious species. 



But you are sure to find the female flowers in the imme- 

 diate neighbourhood of the stems with the male flowers. 

 They are easily recognised by their larger and darker leaves 

 (Fig. 1 8, c)-, and especially by their little twin pods, green, 

 wrinkled, and pedicellate,* which garnish the axil of the 

 leaves. (Fig. 18, d.) From this characteristic the female 

 mercury was formerly mistaken for the male; and many 

 centuries elapsed before naturalists recognised, what now-a- 

 days seems so simple, that the little pods, joined in couples, 

 and containing each a grain, composed the fruit of a single 

 plant; that every fruit proceeds from an ovary; and that every 

 ovary is a sign of the feminine sex. 



In the Historia Naturalis of Pliny, who was at once so 

 acute and so credulous an observer, we first meet with the 

 name of Mercurialis. 



"The plant is so denominated," he says,t '* because it was 

 discovered by Mercury. Its juice, mingled with that of the 

 hibiscus (a species of the Malvaceae) and the purslain, forms 

 a kind of unguent, with which, if you thoroughly rub the 



* A flower with a stalk is called pedunculate or pedicellate ; without a 

 stalk, it is sessile. 



t Pliny, "Historia Naturalis," xxv. 1 8. 



