The ponderosa pine (Pinus ponderosa) is a gymnosperm, that is, it belongs to the group of plants in which seeds are formed exposed or “naked” on sporophylls (spore bearing leaves), as contrasted with angiosperms where the seed is formed within a closed ovary. In conifers, the sporophylls are organized into cones.
The ovulate or female pine cone consists of a central axis with closely overlapping scales (sporophylls). The ovules (female spores and an integument or covering) are borne on the upper surface of the scale close to the central axis. At maturity this is the pine cone that most of us readily recognize and use for Christmas decorations.
The staminate or male pine cone is relatively small and only endures for a few weeks in the spring. Again, there is a central axis or stem with attached scales. The male spores, which develop into winged pollen grains, are located on the underside of the scale. When mature the pollen grains are released in tremendous numbers and appear like a yellow dust or powder in the air. Leonard and I have been at Medicine Lake (Siskiyou County CA) when there was so much pollen in the air it resembled yellow fog. The male pollen grains are blown by the wind to other trees where they fall between the scales of female cones and fertilization occurs.
Female cones are located on the upper branches while male cones are generally located on lower branches. This adaptation makes it less likely that pollen from one tree will fall onto female cones of the same tree, encouraging cross-pollination. Insects do not pollinate pines.
Male ponderosa pine cones are two to three inches long and dark red in our area. In the Rockies the male ponderosa pine cones are more yellowish.
These male ponderosa pine cones were photographed in May at Eagle Lake near the Christie Day Use Area (Lassen County CA).