The stem is underground and is called a rhizome . Spores germinate to form a tiny, heart-shaped gametophyte . Fertilization still requires water, because the sperm must swim to a gametophyte bearing an egg. Once fertilization occurs, the zygote grows into the diploid sporophyte. The female gametophyte is as few as 7 cells and is housed in a structure called an ovule .
Pollination takes place in spring.
Once pollen lands on a female cone, it closes up and the pollen tube grows for 12-15 months before reaching the female gametophyte in the ovule. Once fertilization occurs, the little cone starts to grow. White pine was sought after for ships masts and later fueled the lumber era, along with red pine. Jack pine is pyrogenic, having characteristics that facilitate fire. Fruits are mainly used for dispersal, and also to protect the seeds.