Flowering and Fruiting
Red spruce is monoecious; male and female flower buds open in May in axils of the previous year's shoots on different branches of the same tree. The pendant male flowers are bright red; female flowers are erect and bright green tinged with purple (21). Although cone buds differentiate as early as July preceding flowering in the following spring, they are difficult to distinguish until September. For experienced workers they provide a possible means of identifying seed years at that time. The cones mature from about mid-September to early October, the autumn following flowering (41). Cones are 3 to 4 cm (1.3 to 1.5 in) long, light reddish brown, with rigid, rounded scales often slightly toothed on the edges. Cones are receptive to pollen when fully open, a condition which lasts for only a few days.
- Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm