CHAP. X.] URTICACE^. 161 



the centre of which are five stamens, standing 

 at first erect, but springing back with elasticity, 

 when they discharge their pollen, and remaining 

 extended as shown at b. The anthers open by 

 pores at the extremity of the cells, as in Eri- 

 caceae. The female flowers are produced in 

 close heads (c). They have neither calyx nor 

 corolla, but the ovary of each is protected by a 

 membranous scale. Each ovary has two styles, 

 though it produces only a single seed. As the 

 fruit ripens the styles disappear, and the scales 

 enlarge, so as to give the head of female 

 flowers the form of a strobile or cone (^), the 

 ripe fruit or nut being placed at the base of 

 each scale, as shown at e. The surface of the 

 scales is studded over with roundish glands, 

 which are filled with a substance resembling 

 pollen, called lupuline, w^hich they give out on 

 pressure, as shown at /; and this substance 

 consists of a number of cells filled with volatile 

 oil, which occasion the fragrance of the hop, and 

 contain the bitter and astringent principles 

 which make the hop so useful in compounding 

 malt liquor. The lupuline is also somewhat 

 narcotic; but though the fragrance of hops is 

 said to produce sleep when inhaled in small 

 quantities, an excess of it produces headache 

 and vertigo, especially in nervous persons. The 

 leaves are opposite, and three or five lobed ; 



