Learning About Pine Cones
Male cones (microstrobilus or pollen cone) are herbaceous and produce pollen. They are structurally the same on all conifers, with small differences from species to species. At first glance, they all seemed like cones to me, but now I know what they are. They are growing on a central axis, from modified leaves (microsporophyllis) under which the pollen sacs (microsporangia) are growing.  The male cones are usually colored differently from the female cones, in yellow, red, purple, green or grey. I had these male cones in a a potpourri on my table and I didn't know what they were. They are dry, but still have the male cone form.
The female cones (megastrobilus, ovulate or seed cone) contain ovules which become seeds when fertilized by pollen. The female cones are different from species to species, making possible the identification of many conifer species. The plates of a cone are called scales and they differ from species to species. Female cones have two different types of scales: the bract scales, derived from a modified leaf and the seeds scales, derived from a modified branchlet.
First appear the bract scales, and after pollination the seeds scales develop to enclose and protect the seeds. The cones close during the fertilization, then re-open to let the seeds go. Cones can open and close many times as long as the cone is on the branch, even if all the seeds are gone.
On most conifer species, male and female cones grow on the same tree; usually the female are on the upper part, while the male cones are on the lower branches. The explanation of this particular arrangement of the cones in a conifer tree is very interesting: the male cones grow on the lower branches so they can pollenize the female cones from another tree and not from the same. The wind takes the pollen up in the air, usually over other trees nearby. This way the species will remain strong and live on.
The conifer families have different forms of female cones:
Araucariaceae, is a very ancient conifer family with three genera: Agathis, Araucaria and Wollemia which have globose type of cones.
Araucaria genus is different from the other two because the male and female cones are found on different trees, like the Araucaria araucana also called the Monkey tail tree. I was lucky to see the one in the picture, with male cones, growing in a garden in Italy.
Podocarpaceae is a member of the Antarctic flora and has very different type of cones, berry-like.
Cupressaceae, the Cypress family with the genera cypresses, arborvitae, junipers and redwoods have the bract and seed scales fully fused. The cones are usually small and spherical, like those of Nootka cypress. 
From the cypress family is also the Bald cypress - Taxodium distichum - also called Swamp cypress, one of the few decidous conifer species, meaning it looses its leaves in the fall. When I was living in Bucharest I saw many Bald cypresses in the park, along the lake. One fall I took pictures of their beautiful and interesting cones.
Sciadopityaceae has only one genera endemic to Japan, with cones similar to those in the Cupressaceae family, only larger.
Taxaceae, the yew family, and Cephalotaxaceae have cones with a few scales which develop into fleshy arils.
I have two conifer trees from the Pinaceae family in my garden, a Norway spruce - Picea abies and a Colorado blue spruce - Picea pungens glauca.  Last month I saw many buds forming on their twigs. The first time I saw them last year I thought they were cones. They looked like very small cones, but later in spring I saw new growth sprouting from those "cones". Now I know that they are only buds which will open up in spring. Norway spruce and the Colorado blue spruce will make cones after they reach maturity, after 20 years of growing.
However, one of the Chinese arborvitae (Platycladus orientalis) in my garden is old enough to have cones. They are now open and releasingthe seeds.
A few years ago, while walking through a park, I saw some open thuja cones, picked up a few seeds and started a few plants which are now taller than me. One of them has formed many cones this summer - those are open now. The other thujas have started to form the pollen bags on the branches. They will pollenize the cones which will start growing in the spring. The thuja cones are green and soft at first, then become woody, just before opening to let the seeds out.
I'm happy to have some nice conifers in my garden to study their cones, but I'm also happy for those which aren't making cones yet. Christmas is near, so I might start doing more cone crafts. I will make a pine cone candle holder and a new pine cone Christmas tree. I could use the Loblolly pine cones I already have, but yet a walk in the park for collecting more cones would be nice, while it's still sunny and no snow. I hope you will join me and do some conifer cone Christmas crafts. It's such fun, you'll see!
Merry Christmas everyone!
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, , , , , , ,  - Wikipedia article on Pines
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