Fothergilla L. spp. are valuable nursery and garden plants. However, clear differentiation among F. gardenii Murray, F. major Lodd., and potential hybrids can be difficult based solely on morphological characteristics. The objectives of this work were to verify and describe the existence of interspecific hybrids and to clarify the proper nomenclature for cultivars of Fothergilla that are commonly grown in the nursery industry. A comparison of morphological characteristics was made among diverse clones representing both species and potential hybrids. A combination of chromosome counts and DNA contents was used to clearly differentiate among F. gardenii (2n = 4x = 48), F. major (2n = 6x = 72), and hybrids (2n = 5x = 60). It was determined that the majority of cultivars represented in commerce were hybrids. Fothergilla ×intermedia Ranney and Fantz (hybrid fothergilla) is proposed as the name for these hybrids and is validated with a Latin diagnosis. Although certain morphological characteristics can be used to differentiate between F. gardenii and F. major, the hybrids tend to be intermediate and are particularly difficult to separate from F. major on the basis of appearance. The correct classification and nomenclature for 17 different taxa are presented.

Seven Vaccinium angustifolium clones were tested for low-temperature tolerance over two dormant seasons. Flower primordia in the pseudoapical bud were damaged at higher temperatures than were stem tissue and primordia of the fourth floral bud. The flower primordia located at the stem tip also reacclimated earlier and seemed to show a stronger response to abrupt spring warming than did other tissues tested. Given the lowest survival temperatures determined and the ambient temperatures recorded, we recommend that the physiological and economic aspects of cryoprotectants and flower-delaying treatments be studied further.

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Cornus sericea L. rooted cuttings were held in cold storage for 60 days and then transferred to a growth chamber in hydroponic culture. Roots and shoot tips were sampled during storage and through resumption of vegetative growth. Samples were analyzed for abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin, zeatin riboside, glucose, fructose, sucrose, and starch. Budbreak was associated with increasing levels of the cytokinins and IAA, and decreasing levels of sucrose and starch in the shoot tips. Regeneration of new roots was preceded by an increase in the cytokinins and IAA, and a decrease in ABA in roots. Root sucrose increased nearly two times 1 week after budbreak and starch content generally decreased throughout the experiment. The results agree, in general, with previous reports indicating decreasing levels of ABA and increasing levels of cytokinins to be associated with root regeneration and budbreak. They also indicate that, of the four carbohydrates studied, sucrose levels changed most dramatically during the root regeneration and budbreak processes.