9. Galeopsis L. (hemp nettle)
Ten species,
Europe, Asia; introduced in the New World.
The stamens in
the genus are unusual in their morphology and dehiscence. The two anther sacs
are attached to the expanded connective in a vertical orientation and spreading
from one another. Each anther sac dehisces by two valves in somewhat of a
clamshell pattern. The larger valve of each pair, which is glabrous, dehisces away
from the other anther sac of the stamen and becomes oriented parallel to the
filament. The smaller valve of each pair, which is densely bearded with minute,
bristly hairs, dehisces toward the other anther sac (the two smaller valves of
the pair of anther sacs become oriented parallel to one another and are
positioned more or less erectly after dehiscence). Although the anthers
themselves usually are white or purplish-tinged, the pollen is yellow.