574 



BOTANY 



TART II 



with alternate, exstipulate leaves. Flowers hermaphrodite, the 

 members in many cases arranged spirally. Perianth either forming 

 a simple perigone or differentiated into calyx and corolla. Stamens 

 indefinite. Pollen-grains with at least three places of exit for the 

 pollen -tabes. Carpels three to indefinite, borne on the convex 

 receiDtacle, and forming an apocarpous, superior ovary. Ovules, 



Fio. 557. — Flower oi Ranunculus scclemtus ; h, the same, cut through lougitudiually ; uiaguilied. 



(After Baillon.) 



borne on the ventral suture, singly or in numbers. The partial 

 fruits are follicles, achenes, or berries. Seed with a small embryo 

 enclosed within the large, oily endosperm. 



This family is mainly distributed in the northern hemisphere ; some genera are 

 widely distributed. 



Important Genera. — Many of our commonest meadow and woodland plants 



belong to this order. They are all in greater or less 

 degree })oisonous. Numerous species of Banunculus, 

 characterised by the usually yellow Howers, convex 

 receptacle, and fruit composed of numerous free 

 achenes, occur in Britain. The petals have a nectary 

 at the base. Leaves palmately divided more or less 

 deeply. R. sceleratus is very poisonous (Figs. 557, 

 559). Fc. arvensis with large, spiny achenes or nutlets 

 (Fig. 558). The aquatic species of Banunculus, 

 belonging to the section Batrachium, are often hetero- 

 phyllous (Fig. 37, p. 36), the floating leaves serving 

 to support the flowers above the surface of the water. 

 Species of Anemone are also widely distributed 

 in Europe. A. nemm-osa occurs commonly in woods 

 and is one of our early spring flowers. It has a 

 horizontal, subterranean rhizome, which terminates in a flower, the further growth 

 of the plant being carried on by a lateral shoot. Perianth simple, petaloid. All 

 species of Anemone have at a gieater or less distance from the perianth a whorl 

 of, usually, three leaves forming an involucre (Fig. 560). In A. hcpalica this stands 

 just below the perianth and thus resembles a calyx. All the species are to some 

 extent poisonous, especially A. FuJsatiHa. Many are valued and arc cultivated 

 in quantity during winter, especially on the Riviera, to supply the market 

 with cut flowers. The plants of the genus Clematis are mostly woody and differ 

 from other Ranunculaceae in having opposite leaves. Many species are cultivated 



Fig. 558. — Ranunmlus arvensis. 

 Carpel in longitudinal section. 

 (After Baillon, enlarged.) 



