THE OVULE. 311 



directly towards the apertures. The orifice or foramen of the 

 exterior integument is called the EXOSTOME (or outer mouth), that 

 of the interior, the ENDOSTOME (or inner mouth). The coats of 

 the ovule and the nucleus are distinct and unconnected, except at 

 the base, or point of attachment to the furiiculus, where they are 

 all perfectly confluent : this point of union receives the name of 

 the CHALAZA (Fig. 411, d). 



564. Through the funiculus and chalaza the ovule derives its 

 nourishment from the placenta ; through the opening at the sum- 

 mit, the nucleus receives the influence of the pollen, which results 

 in the production of the embryo. 



565. Our description applies to the complete ovule in its sim- 

 plest form, where no change in the position of parts takes place 

 during its growth, the chalaza remaining next the placenta, with 

 which the funiculus directly connects it, while the apex, represent- 

 ed by the foramen, or orifice of the coats, is at the opposite ex- 

 tremity (as in Fig. 410). Such an ovule, not being curved or 

 turned from its normal direction, is called atropous (literally, not 

 turned), or usually orlliotropous (straight). This simple orthotro- 

 pous form occurs in the Cistus Family (Ord. Cistacese), and the 

 Polygonum Family (Ord. Polygonaceae), and in many others. 



566. In the greater number of cases, however, a change of rela- 

 tive position takes place during the development of the ovule ; con- 

 sisting either in its complete inversion upon the funiculus that bears 

 it, so that the orifice or apex is brought down by the side of the 

 stalk and points towards the placenta, while the chalaza looks in the 

 opposite direction (as in Fig. 413, 414, and also in Fig. 263, where 

 such ovules are seen in their natural position in the ovary) ; or 

 else the ovule curves upon itself, and thus brings down the apex 

 near the funiculus (as in Fig. 416). In the former case, the ovule 

 is anatropous, or inverted ; in the latter, it is campylotropous, or 

 curved. Campylotropous ovules are found in the Mignonette, in 

 all Cruciferous and Caryophyllaceous plants, and in many others ; 

 but the anatropous form is by far the most common of all. 



5G7. In anatropous ovules, the funiculus coheres firmly with 

 that part of the surface which is applied to it ; and in the ripe seed 

 breaks away at the point where it is free from the integument, to 

 which the adherent portion remains attached. The latter receives 

 the name of RAPHE ; and appears in the form of a ridge, cord, or 

 line, passing from the HILUM (as the scar left by the breaking 



