No abstract

An informal experiment on the viability of black spruce (Picea mariana) [Mill.] B.S.P.) seed in or on a boreal forest seedbed indicates that seeds which do not germinate lose their ability to do so some time between 10 and 16 months after seeding. Foresters are cautioned that black spruce cutovers which have not regenerated one year after harvesting that eliminates seed-bearing trees should be seeded artificially or planted. Areas which have not regenerated one year after direct seeding should be reseeded. ResumeUn essai sommaire de viabilit6 des graines d16plnette noire (Picea mariana [Mill.] B.S.P.), sur ou dans des lits de germination de la fordt bodale. indique que les graines qul ne garment pas perdent leur pouvoir germinatif entre 10 et 16 mois aprks I'ensemencement. Les forestiers sont avertis que les coupes d'bpinette noire, qui ne se sont pas r6-g6nerees une annbes aprks une coupe qui Blimine les semenciers, devraient dtre ensemencbes artlficiellement ou plantbes. Les superficies, qui ne sont pas rBgbnbrbes une annbe apr6s un ensemencement direct, devraient dtre r6-ensemensBes.

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The initial stages of panicle, spikelet, and floret development in field-grown 'Kay' orchardgrass were examined using scanning electron microscopy. Spikelets arose from a complex multilevelled sequence of initiation from branch apices. Spikelets developed indirectly in a two-tiered progression: (i) an acropetal and basipetal sequence of first order, second-order, and third-order inflorescence apices, and (ii) an acropetal development within subclusters of higher-order lateral branch inflorescence apices. The panicle had the unique feature of dorsiventrality as well as bilateral symmetry. The basal apex from first-order, second-order, or third-order apices developed on the same side of the main axis as the first-order apex. The two glumes subtending each spikelet primordium developed alternately and acropetally. Development and initiation of florets within spikelets was basipetal within the panicle, basipetal within clusters and subclusters of spikelets on lateral branches, and acropetal within spikelets. Within florets, paleas developed later than lemmas. Key words: Dactylis glomerata, cocksfoot, scanning electron microscopy, development, panicle.

Unopened buds of white spruce (Piceaglauca (Moench) Voss) were damaged by late spring frost. At time of death of the apical meristem the buds were not ready for flushing. As expected on the basis of ground frosts, there was more damage among shorter trees than among taller trees, and more damage among open-grown trees than among understory trees.