FIBEO-VASCtTLAR BUNDLES OF THE OVAKY. 



173 



IS of much interest, and can best be examined under the two 

 heads of " Simple Pistils" and " Compound Pistils." 



486. Simple Pistils. The libro-vascular bundle consists of 

 wood and liber running through the median line of the carpellarj^ 

 leaf, — that is, through the dorsal suture. Two branches are 

 given off by this bundle not far from the base of the leaf, near 

 its two united margins, — that is, at the ventral suture. 



487. The folded carpellary leaf has incurved margins ; so that 

 whatever the arrangement of the wood and liber may be in the 

 median line of the leaf, the reverse will be found at the margins. 

 Thus in each of the three carpels shown in Fig. 133 a, the flbro- 



vaseular bundle running through the dorsal suture has liber on its 

 outside (the unshaded portion) and wood on its inside (the dark 

 portion). But in each of its branches at or near the ventral 

 suture liber occurs on the inside (that is, nearest the centre of 

 the flower) and wood on the outside. 



488. Compound Pistils. If several carpels unite to form a 

 compound ovary, the same inversion of the order of the parts of 

 the bundles (as shown in Fig. 133 a) will be seen when the 

 bundles at the centre of such an ovarj? are compared with those 

 at its periphery (see diagrams b to/, Fig. 133). 



Fig. 133. Transverse section of superior ovaries, sliowing the arrangement of the 

 flbro-vascular bundles of carpels: a, Eranthis hyemalis; b, Hyacinthus orientalis; 

 c, Tulipa Gesneriana ; d, Impatiens tricornis ; e, Anagallis arvensis ; /, Lychnis dioica. 

 (Van Tieghem.) 



