BRACTS AND FLORAL LEAVES. 87 
there may be a petaloid calyx, as in anemone and marsh-marigold, 
or no perianth at all, e.g., willow. 
FIG. 40.—Flower of Rose. Db. 
bract ; ct. cup-like receptacle; 
FIG. 39.—Floral Leaves of White Waterlily. ef. sepals; p. petals; e. sta- 
c. sepal; p. petals; e. stamens. mens. 
The corolla and calyx, when arranged in whorls, are usually 
isomerous, 7.e., they contain an equal number of members, which, 
in this case, regularly alternate with one another. When petals 
and sepals are unequal in number, the former are sometimes 
more numerous (¢.g., poppy, petals four, sepals two), sometimes 
less so (e.g., monkshood, petals two, sepals five). 
The terms hypogynous, perigynous, and epigynous (c¢f. p. 81) 
are applied to the corolla specially, as well as to the flower as a 
whole. 
Prejloration or arrangement of leaves in the flower-bud equally 
concerns both divisions of the perianth (p. 84). 
Cohesion.—When the petals are jree and distinct, as in rose, 
buttercup, and wallflower, the corolla is polypetalous or apopetalous 
(fig. 40). Frequently, however, there is more or less union, with 
formation of a tube, cup, or the like, as in the gamopetalous or 
synpetalous corollas of primrose, Canterbury bell, snapdragon, and 
convolvulus. 
Adhesion.—The commonest union is one between corolla and 
stamens, which will be mentioned later (p. 95). . Compare also 
p. 84. 
External Characters.—The very greatest variety is developed 
in the corolla, which, as a whole, may be radially symmetrical, 
bilaterally symmetrical, or asymmetrical. The individual petals, 
when free, can, like sepals, be described in the same terms as 
foliage leaves. They are usually narrowed at their attached end, 
and, not infrequently, as in the pink (fig. 41), there is a distinc- 
tion between stalk and blade, termed in this case claw and limb, 
There may be, e.g., in ragged-robin and red campion, a small out- 
