DICOTYLEDONS: ARCHICHLAMYDEAE 239 



Order Caryophyllaceae. Herbs with opposite leaves, 

 nodes swollen, inflorescence a dichasium or scorpioid 

 cyme. Flowers regular. Sepals 4-5. Petals 4-5, 

 usually white or pink. Stamens 8-10, the outer 

 whorl usually opposite the petals, hypogynous or 

 sometimes perigynous. Pistil syncarpous, one-celled, 

 placentation free central, ovules indefinite, styles 2-5. 

 The embryo of the seed is curved and surrounds the 

 perisperm. 



The order is a large one, and includes many familiar 

 plants, both wild and cultivated. Many species occur in 

 Britain in very varied habitats, as often suggested by their 

 common names, e. g. : 



Water Chickweed (Stellaria aquatica), Bog Stitchwort (S. uli- 

 ginosa). On the coast we have: Sea Campion {Silene maritima), 

 Sea Purslane (Arenaria peploides), Sea Spurrey (Spergularia rupe- 

 stris), Sea Pearlwort (Sagina maritima). On the mountains: Sea 

 Campion (Silene maritima) , and alpine species of Chickweed (Cera- 

 stium alpinum), Moss Campion (Silene acaulis), Alpine Campion 

 (Lychnis alpina), Pearlwort (Sagina spp.). On walls, rocks, dry 

 banks, and fields : Pinks and Carnations (Dianthus spp.), Chickweeds, 

 Sandworts and Pearlworts. 



In moist woods and hedgebanks : Red Campion (Lychnis dioica), 

 Ragged Robin (L. Flos-cuculi) , Greater Stitchwort (Stellaria Holo- 

 stea), Wood Stitchwort (S. nemorum). As weeds of cultivation : 

 Bladder Campion (Silene inflata), Corn Cockle (Lychnis Githago), 

 Chickweeds (Stellaria media, Sec), Corn Spurrey (Spergula arvensis). 



Many plants of this order are readily distinguished by 

 their opposite, entire leaves and swollen nodes, and also 

 by the inflorescence, which is very characteristic. The 

 main axis ends in a flower (Fig. 165, 2). In the axils of 

 the pair of leaves below, branches arise, each of which 

 bears a pair of leaves. In the axils of the latter leaves, 

 branches arise as before, and so the process may be repeated. 

 The name dichasium or false dichotomy is given to 

 this type of inflorescence. Sometimes one of the branches 

 at a node outgrows the other, and in the later branches 



