Shoots of Acersaccharum Marsh., with at least three long internodes were of two types: long determinate shoots (LDS) usually quickly expanding three or four pairs of preformed leaves and then developing terminal buds; and indeterminate shoots (IS) similarly expanding usually four pairs of preformed leaves and then several pairs of neoformed leaves before developing their terminal buds. The neoformed leaves were smaller, of different shape, and took longer to complete expansion than the preformed leaves. The mature form of the preformed leaves was related to the degree of development of the leaves in the overwintering buds. The last pair of preformed leaves was sometimes intermediate in morphology between earlier preformed and neoformed leaves. The last two pairs of lateral buds on IS were generally formed close together below the terminal bud because internode extension between the last two pairs of neoformed leaves was minimal. On LDS, there was a long internode between the last two pairs of preformed leaves, thus, only one pair of lateral buds was situated close to the terminal bud.
Atypical cones were found in 1983 and 1984 on many trees in three young plantations of Larix laricina (Du Roi) K. Koch. On-shoot and within-crown locations of cones of each type were noted as the cones were collected, at the stage of anthesis or receptivity, for analysis by dissection or sectioning. Development of other cones of each type was monitored. Proliferated seed cones had more bracts than typical seed cones and were commonly located where more vigorous vegetative development (neoformation) was likely. Most bisporangiate cones had proximal microsporophylls and distal bracts; a few also had microsporophylls at their apices. The bisporangiate cones were subdivided according to proportions of different appendages. Those with more female appendages tended to occur on short-shoot axes more distally located along the parent long shoot and thus where more vigorous development was likely. Bisporangiate cones with mainly female appendages developed to seed-cone maturity. Those with mainly male appendages died soon after anthesis. Pollen cones usually have no basal foliage leaves, but some pollen cones with such leaves occurred. The leaves died with the cone tissues after anthesis. Occurrence, composition, and development of these atypical cones were discussed in relation to their position, shoot vigour, and preformation.
Numbers and distributions of seed and pollen cones were assessed on 90 Larixlaricina (Du Roi) K. Koch trees of 5, 6, and 7 years. Respectively, 27, 90, and 96% of the trees bore seed cones and 0, 62, and 96% bore pollen cones. Numbers of seed cones per tree averaged 9, 206, and 390 and of pollen cones, 0, 42, and 838. Ninety-nine, 88, and 30% of the seed cones were borne laterally on long shoots. At ages 6 and 7 years, 22 and 2% of the pollen cones were borne laterally. Seed cones occurred equally on side or lower surfaces of parent long shoots, but pollen cones were mainly on lower surfaces. Lateral cones were mainly borne proximally on the parent long shoots at first production; later, some were medial and a few were distal. Proportions of short shoots bearing seed cones increased acropetally. More short shoots bearing pollen cones were medial than proximal or distal. At age 6, proximal short shoots bearing pollen cones exceeded distal ones: the reverse occurred at age 7. Seed-cone and pollen-cone zones were not separate in the crowns, but within any shoot category, seed cones predominated on stronger shoots and pollen cones on weaker shoots.
[Du Roil K.Koch), which were clonal seed orchards and controlpollinated progeny tests. Production from the seed orchards has been regular and heavy. In only 15 years, most reforestation stock was being grown from orchard seed. Early results from black spruce and jack pine realized gain tests indicate increases of 12 to 20% in volume growth by using genetically improved seed. This is double the prediction that was made when the program started. Stem straightness ofjack pine trees has been improved by 25%. Second-generation programs of black spruce and jack pine are well underway and production from these orchards is steadily increasing. Indications are that gains from using this seed will be substantial. An ongoing research and development program has contributed to a more effective breeding program, has increased seed production, and has given further insights into wood quality. The success of the Council's program is due to excellent participation and team work by government, university and industrial agencies and their long-term commitment.
Trees of Larix laricina (Du Roi) K. Koch reaching the stage of first cone bearing tended to produce the majority of their seed cones, and many of their pollen cones, in lateral (axillary) positions along long shoots. In subsequent cone bearing, a greater proportion of the cones occurred in the typical (for the genus) position terminating short shoots. Some trees 2 to 4 m tall bore over 500 lateral seed cones. Lateral cones occurred on all kinds of long shoots, except sylleptic first-order shoots, produced in the 3-year-old portion of the crown. Lateral seed cones were borne on the morphogenically proximal halves of the long shoots and on all surfaces around the circumference of the shoots, but they were less frequent on upper surfaces than on other surfaces. Lateral pollen cones occurred in the proximal 10% of the lengths of the bearing shoots and were restricted to the undersurfaces or sides of the shoots. Lateral cone buds were distinctively larger and contained more bud scales than adjacent lateral short-shoot buds.
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