BOTANY. 29 
fissiparous division of an original cell called the pollen utricle. The pollen 
grains fall out either singly or united in definite number: sometimes the 
entire mass is combined by viscid matter into conglomerations called pollinia. 
Such is the case in Orchidacez ; here each mass has a prolongation or stalk 
called a caudicle, which sometimes adheres to a prolongation at the base of the 
anther called rostellum, by means of a viscid matter termed retinaculum. 
The part of the column in Orchids where the stamens are situated, is some- 
times termed clinandrium. 
The mature pollen grain has an external covering called extine, and one 
internal, crtine. Within these coverings is contained a granular semifluid 
matter termed fovilla, and composed of small spherical granules sometimes 
sciaa of an inch in diameter, together with larger corpuscules which are 
said to exhibit apparently spontaneous movements. The pollen grains them- 
selves vary from ;+, to ;1, of an inch in diameter, and exhibit highly diversi- 
fied forms. This form is much altered by the application of moisture. This, 
when applied to one side, causes the intine to project outwards and form what 
is called a pollen tube. 
Cryptoeamic plants exhibit certain organs, supposed by some to represent 
stamens, and known as antheridia or pollinaria. These are closed sacs, 
developed in various parts of the plant, either at the surface or concealed in 
its tissue. The contents of antheridia consist of utricles inclosing peculiar 
bodies which have been termed phytozoa, and exhibit active movements 
at certain periods of existence, when they have been taken for infusorial 
animalcula. 
The Disk. By this term is to be understood whatever intervenes between 
the stamens and the pistil. The forms under which it is presented are those 
of hairs, scales, glands, &c., often containing saccharine matter, and forming 
a so-called nectary. The disk may be formed by the degeneration and trans- 
formation of the stamens, 
The Pistit occupies the centre of the flower, being surrounded by the 
stamens and floral envelopes. It constitutes the innermost whorl, and is the 
female organ of the plant, which, after flowering, is changed into the fruit, 
and contains the seeds. Sometimes it is called the gynecium. It consists 
essentially of two parts, the ovary or germen, and the stigma, which is either 
sessile (seated immediately upon the ovary) or elevated on a stalk called the 
style. The pistil, like the other organs, consists of one or more modified 
leaves called carpels. A pistil consisting of a single carpel is simple ; 
otherwise, compound. Each carpel has its special ovary, style (when 
present), and stigma, and is formed by a folded leaf whose upper surface is 
turned inwards towards the axis, the lower outwards; one or more buds 
called ovules being developed at the margin. The ovary then represents the 
limb or lamina of the leaf. The style is generally cylindrical in form, 
and is traversed by a narrow canal, in which there are some loose 
projecting cells forming the conducting tissue, as also elongated tubes at 
the period of fecundation. The stigma is a continuation of the cellular 
tissue in the centre of the style, and may be either terminal or lateral ; 
in the Orchidacez it is placed on a part of the column called the 
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