. The Canadian field-naturalist. 102 The Canadian Field-Naturalist [Vol. XXXIX. Figure 9.—ADVENTITIOUS SHOOTS, PRIMARY AND SECONDARY AXES, ETC. Left "B": adventitious shoot from cut stump of broad-leaf tree (Acer glabrum Torrey) Left "Cl": hole left in trunk by dead lateral branch of Douglas fir (Pseudotsuga taxifolia [Poir.] Britt. Centre: capped stump of Grand fir (A6ies ;! Lindley), showing adventitious shoots- Right: lateral branch of Douglas fir enveloped by wood of the main stem. Second specimen from right: adventitious shoot developed on prostrated primary
. The Canadian field-naturalist. 102 The Canadian Field-Naturalist [Vol. XXXIX. Figure 9.—ADVENTITIOUS SHOOTS, PRIMARY AND SECONDARY AXES, ETC. Left "B": adventitious shoot from cut stump of broad-leaf tree (Acer glabrum Torrey) Left "Cl": hole left in trunk by dead lateral branch of Douglas fir (Pseudotsuga taxifolia [Poir.] Britt. Centre: capped stump of Grand fir (A6ies ;! Lindley), showing adventitious shoots- Right: lateral branch of Douglas fir enveloped by wood of the main stem. Second specimen from right: adventitious shoot developed on prostrated primary axis of Grand fir. Note the fasciation attendant on prostration just commencing on the lower side. twistings and turnings, shapes are more normal. In the lowlands the GIRTH INCREMENT A curious feature in the girth increment of the oak is a tendency for the wood of the stem and branches to form protuberances toward, adhere to, and spread over any rocks that are near the tree. The spread often is in a pancake shape which can take place at the base of the stem or anywhere higher up on the stem or limbs. Protuberances in the wood also often stretch from the stem or limbs toward nearby rock, to which they become firmly attached. Not all the oaks which may be in apparently similar positions with reference to rock show the characteristic and the stem or limbs of any one tree may have mo/e than one of the protuberances. Figure No. 10 shows a case of the pancake-like spread of the wood at the base of an oak over an adjacent boulder. It is apparent that the spread is irregular, being greater in one direction than another, and being upward as well as downward. It is also evident that by the increase in girth the centre of the tree has become poised over the boulder, Figure No. 11 illustrates the case of limb-like protuberance which has grown in this case downward and become attached to a boulder of rock on which it forms a sort of socket which holds the tree to the boulder. No explanati
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