58 PRACTICAL BOTANY. 



and an outer one, testa ^ or jprimiiie — 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 micropyle. Tlie ovule is either 

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

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

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

 into a seed, breaks away, is called the Mhim, 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 arc iirmly united with each other and with 

 the funiculus, w^hen there is any. This point, where coats 

 and nucleus cohere, is called the chalaza. 



108. Ovules occur under four principal forms. The 

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

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

 over upon its elongated funiculus, or upon itself, we 

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

 trojpous (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 (/) 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 campylotrojpous (Fig. 4), when it curves upon itself by 

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

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

 half inverted, remaining straight, and furnished with a 

 raphe (r), extending from the chalaza {c) about half w^ay 

 to the orifice (/). The amphitropous ovule differs from 

 the anatropous merely by the shortness of its raphe. The 

 ortliotropous and campylotropous ovules have no raphe. 



