SEED-BEARING PLANTS 



463 



of two or more petals become wholly or partly fused or 

 coalesced, thus reducing the number of separate members 

 of the corolla (Fig. 346). Sometimes coalescence and 

 petalody of stamens will occur in the same specimen, so 

 that a flower that would normally have five petals may 

 have six or eight, or more, some of which have coalesced, 

 as is indicated by the two or more points at the tip. 



Fig. 346. — Rue anemone {Aitemonella thaliclroidcs). 1, normal flower 

 with s petals; 3, petalody of stamens; 4, coalescence of petals (c^); 2, coales- 

 cence (c), and petalody of stamens. At 2, i is shown a stamen partially 

 transformed into a petal, but with a portion of the anther still remaining. 



412. Mustard Family (Cruciferse). — The flowers of 

 the mustard family are mostly characterized by having 

 the four narrow petals opening out at an angle of 90° 

 from each other, forming a Greek cross (Fig. 347), whence 

 the family name, Cruciferae. This character of the corolla 

 also appears in rare instances in other families {e.g., some 

 Rubiaceae), whose corolla is then said to be "cruciferous." 

 The fruit, a sUiqiie, is also one of the ear-marks of the 



