58 PRACTICAL BOTANY. 



and an onter one, testa, or jpriTtiine — ^are the initial in- 

 teguments of the future seed. The ovule of the Mistletoe 

 has no coats, and that of the "Walnut one only. Both 

 coats remain open at the summit of the ovule, leaving a 

 small passage called the m.icropyle. The ovule is either 

 sessile,- or raised on a stalk, the funioulus. The part by 

 "which the ovule is attached to the cell-wall, tho placenta, 

 or the funiculus, the point where the ovule, when changed 

 into a seed, breaks away, is called the hUum, and then 

 forms the scar of the seed (A in the figures of Cut IX.). 

 The nucleus and the coats are unconnected, save at the 

 base ; here they are firmly united with each other and with 

 the funiculus, when there is any. This point, where coats 

 and nucleus cohere, is called the chalaza. 



108. Ovules occur imder four principal forms. The 

 ovule is said to be orthotropous (Fig. 2) when perfectly 

 straight. But when it is more or less inverted or curved 

 over upon its elongated fimiculus, or upon itself, we 

 have a few terms to express its conditions. It is ana- 

 tropous (Fig. 8) when it is completely inverted on its 

 funiculus, remaining straight ; in this case, a portion of 

 the funiculus adheres to the testa, and is called the raphe 

 (r) ; the orifice or micropyle {f) is close to the point of 

 attachment; and the chalaza (c) occupies the point di 

 rectly opposite to the point of attachment. An ovule 

 is campylotropous (Fig. 4), when it curves upon itself by 

 growing unequally, so as to bring the orifice (/") near to 

 the chalaza (c). It is amphitropous (Fig. 5), when it is 

 half inverted, remaining stra,ight, and furnished with a 

 raphe {r), extending from the chalaza (c) about half way 

 to the orifice (/). The amphitropous ovule di£Eers from 

 the anatropous merely by the shortness of its raphe. The 

 orthotropous and caxnpylotropous ovules have no raphe. 



