100 THE FLOWERING PLANT. 



the filaments is a glandular projection or nectary. The female 

 catkins are green, and a female flower corresponds to the above 

 description, except that, instead of two stamens, there is a pistil 

 formed by two cohering carpels. 



Nettle. — There are two common British forms, the small and 

 the large, which are monoecious and dioecious respectively. The 

 latter kind is easily recognized by its greater size and by its 

 elongated paniculate inflorescences. The small male flowers have 

 a four-lobed calyx, superposed to which is a whorl of four stamens. 

 A minute knob, representing an aborted pistil, is seen in the 

 centre. The female flowers possess a pistil, composed of a single 

 carpel, but no traces of stamens. 



Hop. — The minute male flowers are arranged in cymes. Each 

 consists of a whorl of five sepals, with five superposed stamens. 

 The female inflorescences are short broad catkins, the large over- 

 lapping bracts of which give a cone- like appearance. They form 

 the " hops " of commerce. A pair of female flowers are situated 

 in the axil of each bract. Their perianth is rudimentary, and 

 encloses a pistil formed of two united carpels. 



Ash. — The small flowers are borne in short racemes, and are 

 without perianth. The bisexual ones are provided with two pur- 

 plish-black stamens and a pistil of two united carpels The male 

 and female flowers are similar ; but in one case stamens, in the 

 other carpels, only are present. This is a very interesting case 

 of reduction, for in the flowering ash, a South European species, 

 all the flowers are bisexual, and possess four sepals and four 

 petals, as well as stamens and carpels. This is also the case in 

 the flowers of privet and lilac, both allied forms. 



Cohesion. — The pistil is said to be apocarpous when its con- 

 stituent carpels are free. In buttercup, for example, the small 

 green bodies in the centre of the flower are separate carpels (fig. 

 30) ; here they are very numerous. Instances of smaller numbers 

 are found in columbine (five), larkspur (generally three), and gorse 

 or pea (one). Much more frequently the pistil is syncarpous, its 

 carpels being united, as already alluded to in willow, ash, and 

 hop. The union may be more or less complete. Examine the 

 flower of a saxifrage, such as London pride. A deeply bilobed 

 pistil will be found, evidently consisting of two carpels. In pink 

 or carnation the seed-containing part (ovary) is undivided, but 

 projecting from the top of this are two curved threads (styles), 

 which point to the presence of a pair of carpels. The same thing 

 is indicated by the forked end of the style in dead nettle, sage, 

 and most grasses (fig. 50). In the white lily the existence of 

 three carpels can be recognized by the trilobed stigma, and the 

 three compartments seen in a cross-section of ovary (fig. 38). 



