366 



DICOTYLEDONES. 



odorous) petals; these, however, often become suppressed (Fig. 

 363). The fruit is a capsule. 



a. As many carpels as sepals (4 or 5). Cerastium (Chick- 

 weed). The petals are bifid. Capsule cylindrical, frequently 

 curved at the top, and opening by 10 teeth (Fig. 362). Malachium 



A B C 



FIG. 362. Cerastium arvense : A fruit; B seed; C section of seed. 



differs only in the 5-toothed capsule with bifid teeth. Spergula (Spurry). 

 The petals are not bifid , capsule 5-valved ; seeds winged. The 

 leaves are linear, and appear as if placed in large numbers in a 

 whorl, a branch being situated in the axil of each with leaves 

 placed very close together at its base ; stipules membranous. Sagina 

 has Sn, Pn, An + n, or An, Gn, where n=4 or 5. The corolla is often wanting. 



b. 3 (rarely 2) carpels (Fig. 361 C). Stellaria (Stitchwort) 

 has deeply cleft petals. The number of stamens varies (see above). 



FIG. 363. Arenaria (Halianllius) peploides : (A) and <J -flower (B, C). 



Arenaria has entire petals. (To this group belong Alaine, Moehringia, 

 Halianthus, or Honckenya (Fig. 363), which differ from each other, especially in 

 the form of the seed and number of the capsular valves.) Spergularia has 

 membranous stipules, as in Spergula. Holosteujn. 



2. PAEONYCHIE^E (Figs. 361 D, E, F; 364). Small, greenish 



