Betula pendula (as "B. oycoviensis") was previously listed on the Red List as vulnerable, though it is now considered a synonym of "Betula pendula" subsp. "pendula". "Betula szaferi" was previously considered extinct in the wild on the Red List, but is now considered a form of "B. pendula" with the presence of a mutant gene, causing it to grow weakly and fruit heavily. Silver birch is often planted in parks and gardens, grown for its white bark and gracefully drooping shoots, sometimes even in warmer-than-optimum places such as Los Angeles and Sydney. In Scandinavia and other regions of northern Europe, it is
Citrus gummy bark viroid Citrus gummy bark viroid The citrus gummy bark viroid (abbreviated CGBVd) is a sub-species of the hop stunt viroid, and thus is a member of the genus Hostuviroid. As the name suggests, the citrus gummy bark viroid causes problems in the bark of the sweet orange tree. Scrapping the bark exposes localized spots or a line of reddish-brown, gum-impregnated tissue around the scion circumference especially visible near the bud union. The discoloration and gumming may extend above the bud union to the main branches of the sweet orange while in severe infection dark streaks of gum-impregnated tissue may also be