30 THE FLOWER. 
(58. The pistiLs occupy the centre of the flower. They are 
sometimes numerous, but often only one. They are destined to 
bear the seed. Collectively, they are called gynecium (yvvy, 
pistil, ovxoc, a house). 
59. The recerracte is the swmmit of the flower-stalk, out of 
which the floral organs grow, and upon which they stand in 
concentric whorls, the gyneciwm in the centre, the andrecium 
encircling it, the corolla next without, and the calyx embracing 
the whole. 
60. The principal parts of the flower are shown in the cuts (Figs. 4, 6, 7, &e.), 
or better by specimens, with which, both here and throughout the work, the student 
should always be provided. 
The slender, thread-like organs seen at a (Fig. 4, No. 1), are the stamens, sur- 
rounding the pistil b; ¢ is the perianth, consisting of two similar whorls, the outer 
one a calyx of three sepals, the inner a corolla of three petals, surrounding or 
enveloping the stamens and pistil; at d is the receptacle. At a (No. 2) is the 
inner envelope, the corolla; at b is’ the outer envelope, the calyx or cup, which 
seems to contain the rest of the flower like a cup; at c, below the calyx, are 
certain leafy appendages called bracteoles or bracts. 
a. Let the pupil compare specimens of these and other flowers, whose parts are 
well developed, until he becomes familiar with the appearance of each organ, and 
can instantly apply its name. 
61. A complete and regular flower, therefore, is made up of 
four sets of organs, arranged in concentric whorls. In regard to 
the number and position of the individual organs composing 
these whorls, it is important to observe, 
a. First, that each set consists, theoretically, of the same num- 
ber of organs, that is, if the sepals be 5, there should be 4 petals, 
5 stamens, and 5 pistils; or, if 3 sepals, there should be 3 petals, 
3 stamens, and 3 pistils, &c. 
b. Secondly, the position of the organs in each set alternates 
with those of each adjacent set, that is, the sepals alternate with 
the petals, the petals with the stamens, and the stamens with 
the pistils. 
c. Thus, in a word, the normal structure of the truly symmetrical flower, 
divested of all irregularities, consists of four concentric whorls of organs, the 
organs of each whorl being equal in number, and alternate in position with those 
of the other whorls (Fig. 5;1). This structural arrangement, as will hereafter be 
seen, exactly coincides with that of the leafy branch, agreeably to the beautiful 
