Coniferae are the conifers; pines, firs and their allies. Many conifers are tall forest trees of pyramidal shape; the others are irregularly branched shrubs. The male flowers are either solitary or aggregated in clusters, and fall after shedding their pollen. The female flowers vary in the different genera. Because they tend to spread their roots laterally rather than send them downwards, conifers are often able to grow on the shallowest of soils, where deep-rooting trees would soon die. Research Coniferae