142 



FAIVIILIES OF FLOWERING PLANTS 



The most important genus is Geranium, represented in tliis coun- 

 try and in tlie Old World by numerous species, whose flowers range in 

 size from those of the Carolina cranesbill {G. GaroUnianum) and the 

 herb Robert {G. Rohertlaiuim), to the large-flowered Alaskan species 

 shown in Fig. 123. The cultivated geraniums belong mosth^ iu the 

 genus Pelargonium, distinguished by the somewhat irregular corolla. 

 They have been wonderfully developed by long cultivation and hybrid- 

 ization. The genus Erodium, 

 widely distributed in temperate 

 regions of the Old World, is rep- 

 resented by three native species 

 on the Pacific coast which fre- 

 quently become bad weeds. 

 They are known by the Spanish 

 name of "alfilerilla." 



Family Oxalidaceae. Oxalis 

 Family. Contains about 7 gen- 

 era and 270 species, 250 of which 

 are comprised in the single genus 

 Oxalis. They are herbs of vari- 

 able habit, or in a few instances 

 shrubs. There is remarkable di- 

 versity in the leaves; while usu- 

 ally palmately 3-foliolate they 

 are sometimes pinnate or even 

 undivided and peltate (shield- 

 shaped). The various shapes 

 are shown in the four species of 

 Oxalis represented in Fig. 124. 

 The flowers are solitary or more 

 often in forking cymes; sepals 

 and petals 5, stamens 10-15; 

 ovary 5-celled, usually capsular 

 in fruit. The juice of the plants 

 contains a sour principle due to 

 oxalic acid. The various wild species of Oxalis are known as wood- 

 sorrels; they have white, yellow or purple flowers. South Africa, par- 

 ticularly the Cape region, is the metropolis for these plants, and many 

 varieties now in cultivation have come from there. 



Family Tropaeolaceae. Tropaeolum Family. Consists of a single 

 genus, Tropaeolum, including about 35 species, natives of the higher 

 parts of Central and South America. They are herbs, erect or climb- 

 ing by means of twisting leaf-stalks. The leaves are simple, and pel- 



BA^P 



Fig. 124. Species of Oxalis or sorrel, i. O. versi- 

 sicolor. 2. O. commutala. 3. O. approximata. 4. O. 

 hirta. All one-half natural size. Original. 



