THE FLOWER AND INFLORESCENCE 85 
the pollen sacs face the carpels the stamens are said to 
be InrRorsE, if they face the perianth ExTrRorse. 
When ripe the anther lobes dehisce, liberating the pollen. 
The septum between the two pollen sacs usually breaks 
down so that the contents of both sacs are liberated 
through the same split in the lobe. The dehiscence is 
brought about by the contraction of the cells of the inner 
of the two layers forming the walls of the loculus. This 
layer is cailed the EnporuEcium or Fiprous LAYER. 
The dehiscence may be longitudinal as in the Gladiolus, 
" ‘a 
Fic, 49. Fie. 50. 
A. The androecium and gynoecium of the Cape Crocus. B. Different 
views of the stamens. a. Dorsifixed anther. f. Filament. 
transverse as in some Labiatae, porous as in Heath, or 
valvular as in Cassytha. 
If a stamen possesses no anther, or produces no pollen, 
it is called a StamiInopE. If no filament is present the 
stamens are said to be SESSILE. 
The following terms are used in describing the andr- 
oecium, PoLyanDRous, if stamens are free ; ADELPHOUS, 
if the filaments cohere; MONADELPHOUS, if united to 
form one bundle, e.g. Broom ; DiapELPHOUS, if united to 
form two bundles, e.g. Pea; PonyapELPHous, if united 
to form many bundles, e.g. Orange ; SYNGENESIOUS, if the 
