Pig. 67. — Various forms of pollen grains. Pollen from Typha latifolia (A), 
Zea mays ( B ), Ambrosia elatior (C), Lilium philadelphicum ( D ), Pinus (E), 
Ranunculus bulbosus ( F ), Car pinus caroliniana (G), Althcea rosea (H), Oenothera 
biennis, (/). All highly magnified. Drawing by Hogstad. 
