T. Takaso et Jn. Owens, OVULATE CONE MORPHOLOGY AND POLLINATION IN PSEUDOTSUGA AND CEDRUS, International journal of plant sciences, 156(5), 1995, pp. 630-639
Pollen movement inside ovulate cones was examined in Pseudotsuga and C
edrus. In Pseudotsuga pollen lands on large obliquely inserted bracts
and passes downward to the small axillary ovuliferous scales. Pollen t
hen 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. Pol
len that passes down the adaxial surface of an ovuliferous scale also
may reach ovules of more distal ovuliferous scales. Pollen does not en
ter the area between a bract and an ovuliferous scale. In Cedrus polle
n lands on ovuliferous scales that completely cover the small subtendi
ng bracts. Pollen passes on the ovuliferous scales toward their latera
l bases. The apices of inverted ovules are extended into the area betw
een the ovuliferous scales and the cone axis, Microdrops appear on the
distal surface of the ovules, and pollen adheres to these drops. In C
edrus 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.