594 ON THE USE OF POLLEN 
The group composed of Globularinee, Asclepiadee, Ebe- 
nacee, Oleacee, Myoporinee, Ehretiacee and Plumbaginacee ; 
agreeing in being monopetalous dicotyledons, with superior 
ovaries, albuminous seeds, hilose radicles, and pendulose 
ovules, generally have pollen similar in the characters which I 
have ascribed to the previous dicotyledonous families ; but the 
Asclepiadee possess pollen which, in every point of view, 
must be considered anomalous, inasmuch as I can detect no 
pores in its exine, regarding what are generally called masses, 
as single grains of pollen. E/Aretiacee is another exception, 
having pollen like Salicinee. 
The Plantaginee, Convolvulacee, Polemoniacee and Sela- 
ginee, which agree in being monopetalous dicotyledons, with 
superior ovaries, albuminous seeds, hilose radicles, and sus- 
pended ovules, also agree in the nature of their pollen. 
Such is likewise the case with "the Composite, Valerianacee, 
Dipsacee, Caprifoliacee, Stellate, and Ilicinee, families be- 
longing to different, but nearly allied groups. We see, 
therefore, that a spherical or oval opaque pollen, protruding 
numerous vesicles through pores in the exine, is the kind 
which prevails generally amongst monopetalous dicotyledons 
with definite ovules. 
Those with numerous ovules have, however, a very va- 
riable pollen. Thus, in Gentianee, the pollen is sometimes 
lobed, sometimes oval ; the Scrophularinee generally has an 
oval pollen, becoming spherical in water, and bursting by 
three pores, but in Mimulus it is spherical and hispid. Rhinan- 
thacee and Lentibularie, so closely allied in many respects, 
differ in their pollen. Lobelia has a pollen similar to Sali- 
cinee, while Jasione has this organ like to that of Polemonium. 
It must be acknowledged that this irregularity of pollen 
amongst monopetalous dicotyledons with numerous ovules is 
very remarkable, when compared with its constancy among 
those with few seeds. It is probably an accident depending 
on a higher law, but until we attain to a knowledge of the 
latter, we must be contented with an acknowledgment of the 
facts as observed. It is to be remarked, that the Ericinee 
and Epacridacee alone, among those monopetalous dicoty- 
