16 A FLORA OF MANILA 
The outer row or whorl is known as the calyx, and is commonly green, 
firmer in texture, and smaller than the next inner row; the individual 
parts are called sepals. The next inner row or whorl is known as the 
corolla, which is commonly larger than the calyx, of thinner texture, and 
frequently white or variously colored; the individual parts are called 
petals. Certain flowers in cultivated plants consist wholly of floral 
envelopes, and these are known as double flowers, as in the rose, some 
cultivated species of Hibiscus (gomamela), etc. 
The next inner whorl consists of the stamens, or male organs. A 
typical stamen consists of two parts, a stalk, known as the filament, 
which bears a variously shaped body filled with a fine, yellow, dust-like 
substance, the pollen, this body being called the anther. 
The innermost row or whorl, frequently a single body, is the pistil, 
or female organ, which, when complete, consists of three parts, the ovary, 
style, and stigma; a simple pistil is called a carpel. The ovary is the 
basal, usually enlarged and hollow part, which contains one or more 
ovules or rudimentary seeds; an ovary may be from 1- to many-celled. 
The style is the usually tapering part above the ovary. The stigma is 
a variously shaped, often small, usually apical part of the style with a 
moist surface to which the pollen may adhere. 
As noted above a complete flower is one in which all four of the above 
sets of organs are present. In very many flowers from one to three 
of the sets of organs are absent, such flowers being incomplete. A perfect, 
bisexual, or hermaphrodite flower is one in which the two sets of essential 
organs, stamens and pistils, are present and fully developed, although 
the perianth may be present or absent; an imperfect or unisexual flower 
is one in which either the stamens or the pistils are imperfect or wanting. 
Flowers with stamens and no or only rudimentary pistils are called 
staminate or male, and those with pistils and no or only rudimentary 
stamens are called pistillate or female. 
Unisexual or imperfect flowers are said to be monoecious when both 
male and female flowers are produced by the same individual, as in 
Ricinus communis (tangan-tangan); dioecious when male flowers are 
borne on one plant and female flowers on another as in Antidesma 
(bignay) ; and polygamous when some flowers are perfect, and some male 
or female on the same plant. 
Incomplete flowers are said to be naked when they have neither calyx 
nor corolla, and apetalous when the corolla is absent. When there is but 
one set of floral envelopes present it is always considered to be the calyx. 
Flowers are regular, when all the parts of each set of organs are of 
like size and shape; irregular, when some parts of one or more sets of 
organs differ from other pth of the same set either in shape or size, or 
both. 
A symmetrical flower is one in which the parts of all sets of organs 
are the same in number or in multiples of the prevailing number; an 
unsymmetrical flower is one in which there is a variation from the 
standard number in one or more sets of organs. 
In the use of numerals in describing the parts of flowers they are 
termed 3-merous or trimerous, when the parts are in threes, 5-merous or 
pentamerous when the parts are in fives, etc. Plants with 1, 2, 3, or 
many stamens, are described as monandrous, diandrous, triandrous, poly- 
androus, etc.; if with 1, 2, 3, or many petals, as monopetalous, dipetalous, 
tripetalous, polypetalous, ete. 
