THE SEED. 149 



is a simple, soft mass with no indication whatever of 

 the covering so manifest in ripe seeds of all kinds. Very 

 soon, however, after the appearance of the body of the 

 ovule, a circular ridge is developed upon it, and this 

 gradually extends upwards over the surface so as to form 

 a coat, which at length entirely covers it except at the 

 very apex, where a minute opening is left. Very 

 commonly, but not always, a second coat is developed 

 exactly in the same manner, outside the first, and an 

 opening is left in this coat also, precisely over the other. 

 This minute passage through both coats to the ovule body 

 has already been named the micropyle. The two coats 

 are known as the -primine (generally, though not always, 

 applied to the outer) and the secundine, and the central 

 body is the nucleus. 



245. If the ovule appears to arise directly from the 

 placenta without the intervention of a stalk, it is sessile ; 

 but if a stalk is present, this is known as the funiculus. 

 In the accompanying diagram (Fig. 210) which represents 

 a section of the complete ovule, k is the nucleus ; ai, the 

 primine ; ii, the secundine ; ??^, the micropyle ; /, the 

 funiculus. The point (c) where the two coats and the 

 nucleus are blended together is called the chalaza. The 

 portion of the nucleus marked em is the cavity called 

 the embryo-sac, already referred to in Chapter II. 



246. It must now be pointed out that though the ovules 

 at the commencement of their growth are straight, as in 

 the diagram just described, yet they do not commonly 

 remain so. Very often the ovule bends over so as to appear 

 completely inverted, in which case the funiculus grows 

 fast to one side of the primine, becoming completely fused 



