Van Melle (1947) proposed that juniper cultivars of the Pfitzer Group were of hybrid origin and ascribed the name Juniperus ×media Melle. This purported hybrid of J. chinensis L. × J. sabina L. has not been accepted unanimously by the horticultural community. Random amplified polymorphic DNAs (RAPDs) were used to analyze and establish new evidence for the hybrid origin of the Pfitzer Group, using both parents and seven cultivars of the Pfitzer Group. Principal coordinate analysis (PCO) of 122 RAPD bands demonstrated that samples of J. chinensis cluster tightly together, as do the J. sabina samples. Cultivars of the Pfitzer Group lacked affinity with either species, but stood apart as a distinct cluster. The data support Van Melle's conclusion that the Pfitzer Group is separate from J. chinensis and indicate hybrid origin from parents J. chinensis and J. sabina. We recognize Juniperus ×pfitzeriana (Späth) Schmidt [Pfitzer Group] as the correct name for cultivars of Pfitzer junipers. Juniperus ×media, proposed by Van Melle, was rendered illegitimate because of the earlier name J. media V.D. Dmitriev.
Alice Le Duc, Robert P. Adams, and Ming Zhong
Gary J. Keever and Mark S. West
Uniconazole was applied once as a soil drench (15, 30, or 45 mg a.i./plant) or foliar spray (500, 1000, or 1500 mg liter-1, about 175 ml/plant) to established, field-grown thorny elaeagnus (Elaeagnus pungens Thunb. Fruitlandii) and leyland cypress [× Cupressocyparis leylandii (A.B. Jacks. & Dallim.) Dallim. & A.B. Jacks]. At the end of the second growing season following treatment, shoot dry weights (SDW) of thorny elaeagnus decreased with increasing rates of drench-applied uniconazole, while SDW of plants receiving the foliar application were not affected by increasing rates. Growth indices of leyland cypress, determined twice during the first growing season and at the end of the second growing season, were not influenced by application method or rate. Uniconazole applied as a soil drench at 15 to 45 mg a.i./plant suppressed growth of established thorny elaeagnus for at least two growing seasons, but leyland cypress was not affected by uniconazole drench or foliar spray at tested rates. No phytotoxicity was observed on either species in any treatment during the experiment.