THE FLO WEB. 



53 



and thus a free central placenta is formed (Fig. 129). 

 Examples of this are found in the Purslane, 

 Chickweed, Pinks, etc. 



66. The number of pistils in a flower is ex- 

 pressed by the Greek words: monogynous, 

 meaning one pistil ; digynous, meaning two 

 pistils ; trigynous, meaning three pistils ; tetragynous, 

 meaning four pistils ; pentagynous, meaning five pistils ; 

 polygynous, meaning many pistils. The ovary and calyx- 

 tube may be united, when the former is said to be adher- 

 ent, or inferior (Fig. 111). J£ the adhesion extends half- 

 way up, the ovary is said to be 

 half-inferior. If there is no ad- 

 hesion of the ovary with other 

 parts, it is said to be free, or su- 

 perior (Fig. 109). The ovules, 

 or small bodies which are to become 

 seeds, are enclosed by the pistil ; 

 the latter is, therefore, said to be 

 angiospermous (Gr. angios, ves- 

 sel ; sperma, seed). 



67. In the Pine family the 

 ovules lie exposed in the cone, on 

 the upper surface of the base of 

 the scales. The scale is, therefore, 

 the pistil, and it is said to be gym- 

 (Gr. gymnos, naked ; sperma, seed). If 

 ovules, either of gymnospermous or angiospermous pistils, 

 be examined, they will be found to consist of a central 



'■-nHs, 



nospermous 



Fig. 129. Diagrammatic section of compound ovaries : One-celled, placenta free, 

 central. Fig. 130. Diagrammatic section of an ovule ; po/ tu, pollen-tube ; mic^ 

 micropyle ; ou. in, outer integument ; in. in, inner integument ; e»t. s, embryo-sac ; 

 nuc, nucleus. 



