The graceful fir (Abies gracilis Kom., Pinaceae) in Saint-Petersburg and Leningrad region: history of arboriculture, biological peculiarities and methods of reproduction - Orlova Larisa Vladimirovna; Firsov Gennady Afanasevich; Trofimuk Lev; Karamysheva Anastasia Vladimirovna (Hortus Botanicus, 2020)