XVlll 
OUTLINES OF 
132. Placentas are 
a. rile, when the ovules are attached to the axis or centre, that is, in plurilo- 
cular ovaries, when they are attached to the inner angle of each cell ; in unilocular 
simple ovaries, which have almost always an excentrical style or stigma, when the 
ovules are attached to the side of the ovary nearest to the style ; in unilocular com- 
pound ovaries, when the ovules are attached to a central protuberance, column, or 
axis rising up from the base of the cavity. If this column does not reach the top 
of the cavity, the placenta is said to be free and central. 
parietal, when the ovules are attached to the inner surface of the cavity of a 
one-celled compound ovary. Parietal placentas are usually slightly thickened or 
raised lines, sometimes broad surfaces nearly covering the inner surface of the 
cavity, sometimes projecting far into the cavity, and constituting partial dissepi- 
ments, or even meeting in the centre, but without cohering there. In the latter 
case the distinction between the one-celled and the several-celled ovary sometimes 
almost disappears. 
133. Each Ovule (121), when fully formed, usually consists of a central mass or 
nucleus enclosed in two bag-like coats , the outer one called primine , the inner one 
secundine. The chalaza is the point of the ovule at which the base of the nucleus 
is confluent with the coats. The foramen is a minute aperture in the coats over the 
apex of the nucleus. 
134. Ovules are 
orthotropous or straight , when the chalaza coincides with the base (36) of the 
ovule, and the foramen is at the opposite extremity, the axis of the ovule being 
straight. 
campy lotropous or incurved, when the chalaza still coinciding with the base of 
the ovule, the axis of the ovule is curved, bringing the foramen down more or less 
towards that base. 
anatropous or inverted , when the chalaza is at the apex of the ovule, and the 
foramen next to its base, the axis remaining straight. In this, one of the most fre- 
quent forms of the ovule, the chalaza is connected with the base by a cord, called 
rhaphe, adhering to one side of the ovule, and becoming more or less incorporated 
with its coats, as the ovule enlarges into a seed. 
amphitropous or half -inverted, when the ovule being as it were attached laterally, 
the chalaza and foramen at opposite ends of its straight or curved axis are about 
equally distant from the base or point of attachment. 
§ 12. The Receptacle and Relative Attachment of the Floral Whorls. 
135. The Receptacle or torus is the extremity of the peduncle (above the calyx), 
upon which the corolla, stamens, and ovary are inserted. It is sometimes little 
more than a mere point or minute hemisphere, but it is often also more or less 
elongated, thickened, or otherwise enlarged. It must not be confounded with the 
receptacle of inflorescence (74). 
136. A Risk, or disc, is a circular enlargement of the receptacle, usually in the form 
of a cup {cupular), of a flat disk or quoit, or of a cushion ( pulvinate ). It is either 
immediately at the base of the ovary within the stamens, or between the petals and 
stamens, or bears the petals or stamens or both on its margin, or is quite at the. ex- 
tremity of the receptacle, with the ovaries arranged in a ring round it or under it. 
137. The disk may be entire , or toothed , or lobed, or divided into a number of 
parts, usually equal to, or twice that of the stamens or carpels. When the parts 
of the disk are quite separate and short, they are often called glands. 
138. Nectaries are either the disk, or small deformed petals, or abortive stamens, 
or appendages at the base of petals, or stamens, or any small bodies within the 
flower which do not look like petals, stamens, or ovaries. They were formerly 
supposed to supply bees with their honey, and the term is frequently to be met 
with in the older Floras, but is now deservedly going out of use. 
139. When the disk bears the petals and stamens, it is frequently adherent to, 
and apparently forms part of, the tube of the calyx, or it is adherent to, and appa- 
rently forms part of, the ovary, or of both calyx-tube and ovary. Hence the three 
following important distinctions in the relative insertion of the floral whorls. 
