THE COMMENCEMENT OF THE PHANEROGAMIC FRUIT. 



77 



three receptacular ridges. The ovules are borne on longitudinally-running cushions 

 on the carpels. This class of ovary is found in great variety amongst the 

 Orchidacese (figs. 207 ^ and 207 2, and figs. 212 1-^. 3.4)^ 



Carpels of Two Kinds. 



(14) One series of carpels, destitute of ovules, arise from the margin of the 

 deeply-excavated receptacle, roofing it in. Another series, metamorphosed into 



Fig. 209.— Structure of Phanerogamic Ovaries. 



Longitudinal section of the ovary of Cereus grandifiorus. 2 Ovules on a branched placenta from the base of the ovary of 

 Cereus. » Longitudinal section of the ovary of Uedychium angustifolium. * Dehisced fruit of the same plant. « Trans- 

 verse section of the ovary of the same. « Longitudinal section of an Almond ^ovter (Amygdalus communis). ? Lonj:i- 

 tudinal section of the ovary of the same. ^, » Transverse and longitudinal sections of the ovary of the Willow-herb 

 (Epilobium angustifolum). 1 natural size ; », *, 6, 6 slightly magnified ; 2, 7, 8^ 9 x 10. 



ovule-bearing strings, arise spirally from the inner wall of the receptacle and 

 project into the ovarian cavity. Examples are afibrded by the Cactacere, e.g. 

 Opuntia and Cereus (figs. 209 ^ and 209 ^). 



(15) One series of carpels closes the mouth of the excavated receptacle, as in 

 (14). The other series, bearing the ovules, are filamentous, and arise as a whorl 

 from the base of the receptacle; they are consolidated with a thread-like prolonga- 

 tion of the tip of the axis which runs up as a central column. Example: — The 

 Willow-herb (Epilobium, figs. 209 ^ and 209 9). 



