THE DICOTYLEDOXES 1827 



The corolla is polypetalous (Fig. 1730), consisting of five petals often 

 of large size and brightly coloured; they are also imbricated in the bud. 



Fig. 1730. — Geraniiim pratense. Flower. 



The androecium consists usually of ten stamens, obdiplostemonous 

 in Geranium, consisting of five short outer and five long inner ones. In 

 Erodium there are only five, those opposite the petals being represented by 

 scaly staminodes. In Pelargonium only two to four of the stamens are fertile 

 and in certain species of Geranium, e.g., G. pusiUum, some of the stamens have 

 no anthers. A nectary is present at the base of some of the stamens. 



The gynoecium is syncarpous, composed usually of five carpels which 

 unite to form a chambered ovary and pass upwards to form a well-developed 

 compound style or " beak", which divides at the top into an equal number 

 of slender stigmas. One or two ovules are present in each loculus; each is 

 pendulous and anatropous with the micropyle directed outwards. 



The fruit is a schizocarp. The five carpels with their long persistent 

 styles, here referred to as awns, separate from the central column. In 

 Geranium the one-seeded parts or cocci are dehiscent and the styles roll 

 up with considerable force so that the seeds are shot out. In Erodium and 

 Pelargonium the parts are indehiscent but the sharp-pointed awns are 

 hygroscopic and twist up like corkscrews in dry weather. This not only 

 assists in distribution but also forces the seed into the ground. 



The seed contains but little endosperm and the embryo is more or 

 less bent with the cotyledons rolled or folded on each other. These 

 cotyledons may become green while still enclosed in the seed coat. 



The family comprises some eleven genera containing about 750 species. 

 They are widely distributed in north temperate regions. The genus 



