CHAP, v.] RELATIONSHIP AMONGST PLANTS. 163 



a tube, the tips alone being free ; this type of calyx is 

 termed gamosepalous ; the petals are also grown to- 

 gether, forming a gamopetalous corolla ; five stamens are 

 present, which appear to grow from the inside of the 

 corolla-tube, and are described on this account as epi- 

 petalous ; finally the five carpels with their styles and 

 stigmas are completely grown together at every point ; 

 when the carpels are grown together the constituent pistil 

 is termed syncarpous. In the primrose, although there is 

 a growing together of components of the various whorls, 



o 



o 



Fig. 46. Christmas rose (Hcl- Fig. 47. Primrose (Primula 

 leborm), showing the apocarpous vulgaris) showing the syncarpous 

 pistil. pistil. 



yet the flower is regular, a still later type being illustrated 

 by the snapdragon (Antirrhinum), dead-nettle (Lamium) , 

 honeysuckle (Lonicera), etc., where the flower is irre- 

 gular, due to a difference in size and shape of the com- 

 ponent sepals and petals, for the purpose, already 

 explained, of facilitating the visits of insects. The 

 relative position occupied by the stamens, or rather the 

 particular portion of the flower from which they appear 

 to originate, is of primary importance in the classifica- 

 tion of plants, and requires to be clearly understood. 

 When the stamens grow directly from the thalamus or 



