KERNEL or NUCLEUS, the body of the ovule. In the Mistletoe and some related plants, there is only this nucleus, the coats being wanting. TEGUMENTS, or coats, sometimes only one, more commonly two. When two, one has been called PRIMINE, the other SECUNDINE. It will serve all purposes to call them simply outer and inner ovule coats. ORIFICE, or FORAMEN, an opening through the coats at the organic apex of the ovule. In the seed it is _Micropyle_. CHALAZA, the place where the coats and the kernel of the ovule blend. HILUM, the place of junction of the funiculus with the body of the ovule. [Illustration: Fig. 344. Orthotropous ovule of Buckwheat: _c_, hilum and chalaza; _f_, orifice.] [Illustration: Fig. 345. Campylotropous ovule of a Chickweed: _c_, hilum and chalaza; _f_, orifice.] [Illustration: Fig. 346. Amphitropous ovule of Mallow: _f_, orifice; _h_, hilum; _r_, rhaphe; _c_, chalaza.] [Illustration: Fig. 347. Anatropous ovule of a Violet, the parts lettered as in the last.] 321. =The Kinds of Ovules.= The ovules in their growth develop in three or four different ways and thereby are distinguished into _Orthotropous_ or _Straight_, those which develop without curving or turning, as in Fig. 344. The chalaza is at the insertion or base, the foramen or orifice is at the apex. This is the simplest, but the least common kind of ovule. _Campylotropous_ or _Incurved_, in which, by the greater growth of one side, the ovule curves into a kidney-shaped outline, so bringing the orifice down close to the base or chalaza; as in Fig. 345. _Amphitropous_ or _Half Inverted_, Fig. 346. Here the forming ovule, instead of curving perceptibly, keeps its axis nearly straight, and, as it grows, turns round upon its base so far as to become transverse to its funiculus, and adnate to its upper part for some distance. Therefore in this case the attachment of the funiculus or stalk is about the middle, the chalaza is at one end, the orifice at the other. [Illustration: Fig. 348-350. Three early stages in the growth of ovule of a Magnolia, showing the forming outer and inner coats which even in the later figure have not yet completely enclosed the nucleus; 351, further advanced, and 352, completely anatropous ovule.] [Illustration: Fig. 353. Longitudinal section, and 354, transverse section of 352.] [Illustration: Fig. 355. Same as 353, enlarged showing the parts in section: _a_, outer coat; _b_, inner coat; _c_, nucleus; _d_, rhaphe.]