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 

 Orehidacese (figs. 207 ^ and 207 \ and figs. 212 1- 2. 3. *). 



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. 



1 Longitudinal section of tlie ovary of Cereus grandiflorus. 2 Ovules on a branched placenta from the base of the ovary of 

 Cereus. s Longitudinal section of the ovary of HedycMum cmgustifoUum. * Dehisced fruit of the same plant. 6 Trans- 

 verse section of the ovary of the same. ^ Longitudinal section of an Almond flower (Ainygdalus communis). 1 Longi- 

 tudinal section of the ovary of the same. 8, 9 Transverse and longitudinal sections of the ovary of the Willow-herb 

 {BpUdbium angitstifolwm). 1 natural size ; », 4, 6, 6 slightly magnified ; ^, ^ ^^ 9 x 10. 



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

 project into the ovarian cavity. Examples are afforded by the Cactacese, e.g. 

 Opvmtia 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 2093). 



