Eastern shade-tolerant conifers

Picea rubens Sarg. - red spruce

Image 1. The leader and distal lateral branches of a small sapling in October: note (1) that the leaves tend to "hug" the leader, and to be distinctly forward-pointing on the branches, (2) that the foliage is bright, shiny yellowish green, (3) that the distal lateral branches arise over a considerable distance along the leader of the previous year, and do not form a light whorl, (4) that there is a section of the previous leader that bears leaves above the most distal lateral branch and below the position where the terminal bud occurred, and (5) that a similar cluster of leaves hides the terminal bud on the new leader.

Image 2. A vigorous leader of a tree in the seedling stage of development displaying many sylleptic (neoformed) branches, April, after overwintering.

Image 3. A group of saplings, displaying in October their bright, shiny, yellowish-green foliage that distinguishes the species from other eastern spruces.

Image 4. Saplings as in No. 3.

Image 5. A shoot system showing how the leaves are carried along the shoots, September: note that leaves in the axils of which lateral buds occur are angled more away from the shoot than are other leaves.

Image 6. Inside an 85-year-old stand growing on a moist feather-moss site, late July.

Image 7. Pollen cones shortly after emergence from their buds, early June.

Image 8. Expanding pollen cone in a terminal position, early June: note the erect orientation of the cone and the erosely margined, spirally arranged microsporophylls.

Image 9. A terminal and a distal lateral pollen cone at the pollen-shedding stage, early June.

Image 10. A terminal pollen cone at the pollen-shedding stage in early June: note that the portions of the microsporophylls that bear the pollen sacs are oriented horizontally, and the purple, broadly flattened, erosely margined, microsporophyll tips are oriented more vertically.

Image 11. A terminal and two distal lateral pollen cones after pollen shedding as the cones shrivel, and turn brown, late June.

Image 12. Terminally situated seed-cone buds swelling in mid-May.

Image 13. Seed cones beginning to emerge from their buds in late May: note that some of the inner bud scales have elongated and have been stretched in cap-form over the expanding seed cones, continued expansion of the cones will rupture the bud scales and the "bud caps" will be blown away (see No. 14, and then Nos. 17 and 19 to 23, which are of the same cones).

Image 14. The same seed cones as in No. 62, 4 days later when three of the cones are fully receptive to pollen, and the fourth one (third from the left) has suffered insect damage and slowed its development (see also Nos. 17 and 19 to 23): the receptive cones are erect and have the tips of their ovuliferous scales reflexed beyond the bracts (just visible beneath some of the scales).

Image 15. Seed cones at the receptive stage of development, mid-June: the extending ovuliferous scales have their tips reflexed beyond the bracts which remain small beneath the scales.

Image 16. A receptive seed cone in mid-June: this is of a less-common darker shade of purple than the cones of Nos. 14 and 15.

Image 17. The three still-living cones of No. 14 with their ovuliferous scales becoming appressed to close the cones, and the cones themselves beginning to bend at their bases to become pendent, early to mid-June, 11 days later than No. 14 (see also Nos. 19 to 23).

Image 18. Enlarging, closed seed cones in the process of assuming a pendent orientation, mid-June: the two cones to the lower right that have been killed by insect activity remain erect and have shrivelling cone scales.

Image 19. The seed cones of No. 17, in mid- to late June, 10 days later than No. 17, becoming pendent: there is evidence of insect feeding on the cone at the left (see also Nos. 20 to 23).

Image 20. The remaining seed cones of Nos. 13, 14, 17 and 19, almost pendent in late June (7days later than No. 19): note, in the background, that vegetative development (shoot expansion) is now under way.

Image 21. The seed cones of No. 20 fully pendent in early July (13 days later than No. 20) when cone growth has been almost completed (see also Nos. 22 and 23): the resin exudation on the cones at the left is symptomatic of earlier insect damage.

Image 22. The full-grown seed cones of Nos. 13, 14, 17, and 19 to 21 in mid-August (see also No. 23).

Image 23. The full-grown, mature seed cones of Nos. 13, 14, 17, and 19 to 22 in mid-September when the cone scales are beginning to show the browning associated with cone drying: these cones opened two weeks later.

Image 24. Open seed cones in June of the year following cone maturation, cone opening, and seed shedding: the majority of seeds fall from late September through to late October, only a few, usually poorer seeds, fall through the winter; the cones drop from the trees during the year following cone maturity.

Image 25. Winged and de-winged seeds: among the winged seeds above the scale bar, which is divided in millimetres, are some showing the exposed undersides of the seeds with the wing base clasping the two long edges of the seeds (seeds can be individually removed from the wing base and then replaced within the clasping grip) and some showing how the wing base covers the other, or upper, surface of the seeds.

Image 26. A comparison of seed cones of Picea rubens (left) and Picea mariana (right) at the end of June, at the stage of development about two weeks from full cone size: note the darker colour and the greater involvement of the basal region of the cone in bending (to the pendent state) in the P. mariana cone (see also Nos. 27 to 29).

Image 27. A comparison of the undersides (abaxial sides) of ovuliferous scales from the mid-regions of the seed cones of No. 26, the scale of Picea rubens is on the left and that of Picea mariana is on the right: the small bract that subtends the scale of P. mariana is clearly visible; that of P. rubens is less obvious as it is somewhat shrivelled and pushed somewhat to the right of where it would have been before the structures were dissected out: the generally darker colouring of the portion of the P. mariana scale that was exposed in the closed cone is evident (see also No. 28).

Image 28. A comparison of the uppersides (adaxial sides) of the ovuliferous scales of Picea rubens (left) and Picea mariana (right) shown in No. 27: developing seeds and seed wings are clearly evident, as are the darker shades of the P. mariana structures.

Image 29. Comparison of a mature seed cone of Picea rubens (left) with mature seed cones of Picea mariana (right) in mid-September: note the darker colouring of the P. mariana cones and how drying of the cone scales in both species progresses from the tips of the scales towards their bases.

Information provided by:
Dr. G.R. Powell
Faculty of Forestry and Environmental Management at UNB