Populus ×jackii Sarg. - syn.Populus ×gileadensis Rouleau; Populus manitobensis Dode; Populus candicans auct. - Betulaceae
balm-of-Gilead, Jack's poplar

Tree, hybrid of P.balsamifera and P.deltoides, native to North America.

„The tree is named after the unrelated biblical Balm of Gilead, a commiphora resin. Its leaf buds are coated with a resinous sap with a strong, pleasant turpentine or balsam odor that is most evident as the leaves unfold in the spring. For purposes of commerce, the buds are collected before they open, and can be cut up for pot-pourri or used in herbal medicine.“
http://en.wikipedia.org/wiki/Populus_%C3%97_jackii

„The constituents in alcoholic extracts of Populi gemma [buds of black poplar, Populus nigra] and propolis have been compared and shown to be similar in many respects. Honey bees collect the exudate from poplar buds and incorporate it into propolis, a material they use to seal their hives. Propolis is also a source of some folk medicines and alcoholic extracts of it are used in eastern Europe as a mild natural antibiotic… early setlers in New England used the name Balm of Gilead for an alcoholic ex­tract (tincture) of poplar buds collected from Populus candicans Ait. This tincture has bactericidal fungicidal and generally soothing properties.“
Compounds identified in bud extracts of P. candicans included several chalcone and dihydrochalcone derviatives, and volatiles like bisabolol (16.1%), (E)-nerolidol (1.1%), cinnamic acid (E 3.1%, Z 0.1%), α-bergamotene and β-farnesene.
[Populus candicans and the Balm of Gilead., Whatley, F.R., Greenaway, W., May, J., Zeitschrift für Naturforschung C, 44(5-6), 1989, 353-356]

The bud exudate of P.x jackii contains compounds characteristic of both Populus balsamifera (cinnamic and coumaric acids, dihydrochalcones, terpenoids) and Populus deltoides (flavanones, especially the methylated or esterified in the 3 position), indicat­ing its hybrid origin.
[Hybrid origin of Populus x Jackii confirmed by gas chromatography-mass spectrometry analysis of its bud exudate., Greenaway, W., Davidson, C.G., Scaysbrook, T., May, J., Whatley, F.R., Z Naturforsch, Vol.45c, 1990, 594-598]
http://zfn.mpdl.mpg.de/xtf/data/Reihe_C/45/ZNC-1990-45c-0594.pdf

Populus candicans Aiton
Lounsberry, A., Rowan, E., A guide to the trees, t. 26 (1900) [E. Rowan]
http://plantgenera.org/species.php?id_species=1267696