cuttings in an atmosph"t" "r.r"fffT"T$ Tar The chrysanthemum cuttings were treated with 3-indol-butyric acid at 1,000 ppm, and the softwood and evergreen cuttings with 3,000 PPT'-Po1e1-tilla and chrysanthemum cuttings were lifted after 2 weeks and weigela, thuja and iuniper cuttings after 4-8 weeks.The number of roots per cutting was counted and their,length was measured. Potentilla and chrysanthemum cuttings were weighed before inserting and again after lifting.The data from the growth rooms and the mist frames were analyzed statistically by the r test oisignificance. Growth Rooms RESULTSIn the growth rooms, the atmosphere enriched with CO, significantly-increased the rooting percentage and produced more roots Per cutting (Table 1)

Twenty-four morphological characters of native Manitoba Populus were studied in an attempt to delineate species and variants and provide keys for correct identification. The results support the hypothesis that the variants have originated from intersectional hybridization of P. balsamifera L. (section Tacamahaca Spach.) and P. deltoides Marsh. var. occidentalis Rydb. (section Aegeiros Duby). Populus × jackii Sarg. encompasses the collective group of individuals resulting from this hybrid cross. The hybrid individuals are widely distributed and occur commonly where the two parental species are growing together.

RONALD, W. G., L. M. LENZ, and W. A. C U M~I I N G .1973. Biosystematics of the genus Popllllls L. 11. Chemotaxonomy, phenology, fertility, and segregates of native Manitoba species and variants. Can. J. Bot. 51: 2443-2450. Chemotaxonomical, phenological, fertility, and hybrid segregation characteristics have further el~~cidated the relationships of Poplllrls species and variants in southern Manitoba.S ecies chromatograms, made with bark collections from widely separated localities, were consistently unigrm and proved reliable for species identification. Chromatograms of variant individuals were unlike those of any species examined. Flowering and seed shedding in P. balsai71ifera L., P. delloides Marsh. var. occiderzrnlis Rydb., and variants occurred together and about 2 weeks and 4 weeks later than respective dates for P. rrei7111loicles Michx.Hybrid fertility, measured by seed set was lower than the expected values for fully fertile hybrids of P. bnlsan~ifera and P. rleltoi(1es var. occider~trrlis. All variant pop~~lations, except from Grand Beach, produced greater than 90% vigorous seedlings. Seedling progenies from several apparent F1 hybrids segregated towards P. bnlsanl~era and P. deltoides var. occide~~mlis. No segregates similar to or approaching P. trenillloides were recovered. RONALD, W. G., L. M. LENZ et W. A. CUMMING. 1973. Biosystematics of the genus Poprrllls L. 11. Chemotaxonomy, phenology, fertility, and segregates of native Manitoba species and variants. Can. J. Bot. 51: 2443-2450. Des caracteristiques ayant trait k la chimiotaxonomie, b la pht~~ologie, h la fertilite et B la segregation des caractkres chez les hybrides ont clarifiC les relations entre les espkces et les variantes de Poprrllls dans le sud de Manitoba. Les chromatogrammes, effectuts h partir de collections d'kcorces provenant de localites trks eloignees les unes des autres, Ctaient toujours uniformes pour une espece donnee et se sont donc rCvelCs comme des caractkres scrs pour l'identification des espkces. Les chromatogrammes obtenus de variantes n'etaient semblables B aucun de ceux des espkces itudiies. La floraison et la Liberation des graines chez P. balsnmifera L., P. rleltoides Marsh. var. occidetztalis Rydb. et les variantes se produisent au m&me moment, mals environ deux et quatre semaines plus tard, respectivement, que chez P. tret~ltloides Michz.La fertiliti des Ilybrides, mesurCe par le nombre de graines, avalt une valeur plus basse que les valeurs attendues pour les hybrides complktement fertiles entre P. balsan~ifercl et P. deltoides var. occidetztalis. Toutes les populations de variantes, sauf celles provenant de Grand Beach, ont produit plus de 907, de plantules robustes. Les plantules provenant des graines de plusieurs plantes apparemment hybrides de FI ont montri une segregation en direction de P. babun~ifera et de P. rlelroides var. occidetztnlis. Aucun sigrigat semblable au P. treinllloides ou s'en approchant n'a Cte rencontri.[Traduit par le journal]

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