MORPHOLOGY OF REPBODUCTIVE ORGAKS 179 



2. Insertion or Position or Adhesion. — Wheii the stamens 

 are free from the calyx and pistil, and arise from the thalamus 

 below the latter organ, as in the Barberry (fig. 398) and Crow- 

 foot {fig. 366), they are said to be hypogijnoiis ; this is their 

 normal position. When the stamens are attached to the corolla, 

 as in the Primrose (fig. 367) they are e^iipetalous. When they 

 apparently adhere to the calyx more or less, so that their posi- 

 tion becomes somewhat lateral to the pistil instead of below it, 

 as in the Cherry (fig. 868), they as well as the corolla are said to 

 be jierigynous. When the thalamus or the calyx is adherent to 

 the ovary so that the calyx appears to arise from its apex, the 

 intermediate stamens and petals or corolla are also necessarily 



Fig. sey. 



Fig. :-i(W. 



Fiij. 366. Apocarpous pistil of tlie Cru\vfoot ( /^rtH«»cH^H.s),\\itli two stamens 



arising from tlietlialamus below it, or hypogynous. Fi'j. 367. Vertical 



section of a flower of the Primrose {Primula)^ showin ^ epipetalous stamens. 

 Tile pistil in the centre has an ovary with a free central placenta, one style, 



and a capitate stigma. Fig, 368. Vertical section of the flower of the 



Cherry, showing the perigynous stamens surrounding the pistil. 



placed on the summit, and are said to be cpigynous, as in the 

 species of Campanida (fig. 369) and Ivy. It sometimes happens 

 that the stamens not only adhere to the ovary or lower part of 

 the pistil, as in the epigynous form of insertion, but the upper 

 part of the stamen or stamens and that of the pistil become com- 

 pletely united also, and thus form a column in the centre of the 

 flower, as in the Orchis (fig. 370) and Birthwort (fig. 371) ; this 

 column is then termed the gynostemium, and the flowers are said 

 to be gynandrous. 



3. Union or Cohesion. — When the stamens are perfectly free 

 and separate from each other, as in the Vine (fig. 344), they are 

 said to he free or distinct \ when united, as in the Mallow (fig. 

 373), they are coherent or coimate. 



