204 THE STORY OF PLANT LIFE 



last group, the Pea and Vetch group. Other groups 

 to which the Rose group is related are Calycan- 

 thacese, Combretacese, and Thymelasacese. 



There are some two thousand species and ninety 

 genera, of cosmopolitan distribution. Most of the 

 plants are perennials, and include trees, shrubs, and 

 herbaceous plants. 



The leaves are alternate, sometimes opposite, 

 simple or compound, with leaf-like stipules, some- 

 times adnate to the leafstalk. In this group pro- 

 pagation takes place vegetatively by creeping stems, 

 or off-sets, as in the strawberry, by runners, or in the 

 raspberry, by suckers. 



The flowers are in terminal racemes or cymes, 

 very variable in form. Owing to the hollowing out 

 of the receptacle the perianth members are frequently 

 perigynous. The carpels may be borne on a raised 

 structure in the centre, even if the receptacle is cup- 

 like. In Pj^ms and others the carpels are united to 

 the receptacle and inferior. 



The flowers are regular, actinomorphic, and her- 

 maphrodite. The calyx is gamosepalous, of five 

 sepals (or four, or eight or ten), either inferior or 

 superior, with the perianth epigynous or perigynous, 

 usually enclosing the ovary or adherent to it. 



In the Cinquefoils there is an epicalyx of outer 

 smaller leaves, usually overlapping in bud. The 

 corolla is generally polypetalous, with five petals, and 

 regular, perigynous, often round and hollow, with 

 short or no claws, deciduous, overlapping in bud. 



