Ovulate Cone Morphology and Pollination in Pseudotsuga and Cedrus

Abstract

Pollen movement inside ovulate cones was examined in Pseudotsuga and Cedrus. In Pseudotsuga pollen lands on large obliquely inserted bracts and passes downward to the small axillary ovuliferous scales. Pollen then moves toward the cone axis either on the ovuliferous scales or on the bracts near the margin of the ovuliferous scales. Bract bases are curved, which funnels pollen to the apices of the inverted ovules. Pollen that passes down the adaxial surface of an ovuliferous scale also may reach ovules of more distal ovuliferous scales. Pollen does not enter the area between a bract and an ovuliferous scale. In Cedrus pollen lands on ovuliferous scales that completely cover the small subtending bracts. Pollen passes on the ovuliferous scales toward their lateral bases. The apices of inverted ovules are extended into the area between the ovuliferous scales and the cone axis. Microdrops appear on the distal surface of the ovules, and pollen adheres to these drops. In Cedrus rain water carries pollen adhering to the outside of the ovules to the inside. Hydration of pollen by this water has little effect on germination. A pollination drop is produced in Cedrus