326 THE CLASSIFICATION OF PLANTS 



erect ovule; fruit an angular nut; seed endospermous. The 

 stems are mostly herbaceous and bear alternate leaves, which 

 possess membranous tube-like stipules (the ochred) clasping the 

 stem. Common plants of this Order are Dock and Sorrel 

 {Rumex), Knot-grass {Polygonum aviculare L.), Black Bindweed 

 (Polygonum Convolvulus L.), and Buckwheat (Polygonum Fago- 

 pyrum L.). 



Order. ChenopodiacecB. — This Order which is described in 

 chapter xxvi., possesses close affinities with the Caryophyllacea 

 mentioned below. 



(2) Flowers, usually with both calyx and corolla present. 



(a) Flowers hypogynous : gynaecium apocarpous. 



Order. Ranunculacece. — Flowers mostly regular, with free 

 sepals, numerous stamens and one or many free carpels. The 

 fruit is an achene or a follicle. Most plants of the Order are 

 herbaceous and contain acrid poisonous juices. Common examples 

 are Buttercups (Ranunculus), Columbine (Aquilegia), Monkshood 

 (Aconitum), and Anemone. 



(b) Flowers hypogynous : gynsecium syncarpous. 

 (i) Ovules on a free-central placenta. 



Order. Caryophyllacece. — Flowers regular with four or five 

 persistent sepals and the sSme number of petals : stamens usually 

 eight or ten ; fruit a capsule with one or many endospermous 

 seeds. The stems have opposite leaves and thickened nodes 

 ind the flowers are generally pink or white. Common examples 

 are Pinks and Carnations (Dianthus), Campions (Lychnis), Chick- 

 weed (Stellaria), and Spurrey (Spergula). 



(ii) Ovules on parietal placentas. 



Order. Papaveracea. — Flowers regular with two sepals, four 

 petals and many stamens. Fruit a capsule dehiscing by pores 

 and containing many small endospermous seeds. Plants belong- 

 ing to this Order contain milky or coloured latex and are often 

 poisonous : poppies are common examples. 



Order. Cruciferce. (see p. 363). 



(iii) Ovules on axile placentas. 



Order. Linacece (see p. 389). 



