irORPHOLOGY OF REPE.ODUCTIVE (JKGANS 217 



easily counted, when the ovuJes are said to be definite, as in 

 ^senilis (firj. 480), — and the ovary or cell is then described as 

 biovulate, triovulate, &c. ; or the ovules may be very numerous 

 vyhen the ovary is muUioviilate and the ovules indefinite, as in 

 Cerastiiim (fig. 436, g). 



b. Position. — The position of the ovules with regard to the 

 cavity or cell in which they are placed is also liable to vary. 

 When there is but one ovule, this may arise at the bottom of 

 the ovarj- or cell and be directed towards the summit, as in 

 Compositte and Polygonacese (fig. 476), when it is said to be 

 erect ; it may be inserted at the summit of the ovary and be 

 turned downwards, as in Hippuris (fig. 4,11), in which case it 

 is pendvlous ; if it is attached a little above the base, and 

 directed obliquely upwards as in Parietaria (fig. 478), it is 



Fig. 475. 



Fig. 476. 



Fii/. 475. Bract or carpellary leaf, sc, of a species of Piniis, bearing two naked 



ovules, ov, at its base. mic. Micropyle or foramen. Fui. 476. Vertical 



section of the fruit of a species of Rumex {Polygonacete'). p. Enlarged 

 calyx surrounding the fruit. The fruit contains a single erect orthotropous 

 seed. The position of the ovule in the ovary is also described as erect and 

 ortliotropous. The embryo is inverted or antitropous. 



ascending; if, on the contrary, it arises a little below the 

 summit, and is directed obliquely downwards, as in the Mezereon 

 (fig. 479) and Apricot, it is suspended ; if from the side of the 

 ovary, without turning upwards or downwards, as in Crassula, 

 it is horizontal or peltate. In some plants, as in Armeria (fig. 

 440),' the ovule is suspended from the end of a long funiculus 

 arising from the base of the ovary ; such an ovule is frequently 

 termed recUnate. 



In the above cases the position of the ovule is in general 

 constant, and hence this character is frequently of much impor- 

 tance in distinguishing genera, and even natural orders. Thus, 

 in the Oompositse the solitary ovule is always erect ; while in 



