282 PHARMACEUTICAL BOTANY 
This becomes cuticular. The cellulose inner layer (endospore or 
intine), remains unaltered. In the development of the exospore, 
one to several deficiencies are usually left in it through which the 
endospore may protrude later as the rudiment of the pollen 
tube. These are called germ pores. 
ATTACHMENT OF ANTHER.—The attachment of the anther to 
the filament may be in one.of several ways, as follows: 
Innate, attached at its base to the apex of the filament. 
Adnate, adherent throughout its length. 
Fic. 198. Fic. 199. 
Fic. 198.—Orchid Pollinia (~), composed of masses of pollen grains, with 
caudicle (c), and disc or retinaculum (r). (After Small.) 
Fic. 199.—Upper part of Orchid flower, showing the retinacula (a) in place 
within the vostellum or sterile stigma. (After Small.) 
Versatile, when the anther is attached near its center to the top 
of the filament, so that it swings freely. The adnate and versatile 
types are introrse when they face inward, extrorse when they face 
outward. 
Po._en.—The pollen grains or microspores vary in form for 
different species and varieties and while they are averagely 
constant for these, nevertheless, many exceptions have been 
recorded. The following are some of the commoner forms: 
Four Spore Daughter-cells, hanging together, as in the Cat Tail 
( Typha), forming a pollen grain. 
Elongated, simple pollen grains, as in Zostera. 
Dumb-bell shaped, as the pollen of the Pines. 
Triangular, as in the Evening Primrose (CEnothera) and Clove. 
Echinate, as in the Malvaceae. 
Spherical, as in Geranium, Cinnamon and Sassafras. 
