22 September 2024.
York County, Pennsylvania, United States
Locality: Outcrops along the Susquehanna River, accessed from the Historic Lock 12 parking lot off of Pennsylvania Road 372.
Coordinates: 39.8162, -76.3307
(Map it)
Elevation: 38m.
Georeference protocol: Lat/lon determined by GPS
Habitat: Wild Habitat
Environment description: Plants are growing from shade to part-sun and occasionally full sun in crevices of the outcrops and where organic debris has accumulated in between boulders along the Susquehanna River. The sites range from nearly xeric to mesic, at least on the surface. Plants are generally growing 4-10 m above the normal flow of the river; however, the Holtwood Dam is less than 1 kilometer upstream and debris found trapped in the boulders indicates that there is periodic flooding, at least, in the lower zone of 4+ meters or so above normal river flow. This habitat has a diverse assemblage of deciduous trees and shrubs as well as abundant herbaceous taxa. Slope: 0 to 75 percent. Aspect: Northeast (generally). Geology: The underlying geology of this area is probably of lower Paleozoic age and characterized as the Octoraro Formation. It includes albite-chlorite schist, phyllite, some hornblende gneiss, and granitized members. Soils: The area where this species occurs is right on the edge of two soil zones that transition from the river’s edge to mesic conditions upslope. The first is generally referred to as Rock Outcrop. This terrestrial matrix in which plants grow is largely exposed underlying rock geology with accumulated outwash, rock decomposition, and organic debris buildup. The second is Mt. Airy (80%) and Manor (20%) Series soils, 25 to 60 percent slopes, extremely stony (MRF). (Source: California Soil Resource Lab/NRCS Official Soil Series Descriptions). EPA Ecoregion (Level III): Northern Piedmont (64). EPA Ecoregion (Level IV): Piedmont Uplands (64c).
Number of plants sampled: 20
Associated species: Baptisia tinctoria; Fagus grandifolia; Alnus serrulata; Collinsonia canadensis; Amorpha fruticosa; Toxicodendron radicans; Schizachyrium scoparium; Solidago bicolor; Solidago racemosa; Vaccinium angustifolium; Acer rubrum; Acer saccharinum; Aronia melanocarpa; Betula nigra; Vaccinium stamineum; Vaccinium corymbosum; Hypericum prolificum; Ionactis linariifolia; Rubus sp.; Fraxinus pennsylvanica; Viburnum dentatum; Quercus montana; Nyssa sylvatica; Malus sp.; Platanus occidentalis; Symphyotrichum sp.; Ageratina altissima; Chionanthus virginicus; Phlox subulata; Lonicera japonica; Rosa carolina; Hamamelis virginiana; Physocarpus opulifolius; Crataegus sp.; Kalmia latifolia; Rhododendron periclymenoides; Sedum sarmentosum; Parthenocissus quinquefolia; Prunus serotina; Diospyros virginiana; Amelanchier sp.; Cornus amomum [listed as Swida amomum]; Heuchera americana; Asplenium platyneuron; Eutrochium sp.; Carya glabra; Lindera benzoin; Asimina triloba; Ulmus americana; Viburnum prunifolium; Lonicera maackii; Uvularia sessilifolia; Clematis virginiana; Solidago juncea; Vitis sp.; Ilex verticillata; Carya cordiformis; Reynoutria japonica; Polystichum acrostichoides; Athyrium filix-femina; Eurybia divaricata; Tilia americana; Betula lenta; Quercus rubra; Rubus phoenicolasius; Liriodendron tulipifera; Veronicastrum virginicum; Sedum ternatum; Aquilegia canadensis; Thalictrum pubescens; Vaccinium pallidum; Pycnanthemum tenuifolium; Ambrosia artemisifolia; Cystopteris sp.; Carpinus caroliniana; Chelone glabra; Asplenium trichomanes; Onoclea sensibilis; Rhus copallinum.
Comment: This species is a multi-stemmed, deciduous shrub ranging from 0.2 to 2.2 m tall and wide. Unlike most native azaleas, the stems of current season’s growth are glabrous and reddish-brown. Flower buds are imbricate and lanceolate to lanceolate-ovate with a long acuminate tip; imbricate bud scales are glabrous with eglandular ciliate margins. Leaves are simple, alternate, and deciduous; the petiole is glabrous, occasionally, multicellular eglandular-hairy. The leaf blade is ovate to obovate, 3-8 cm long x 1.5-4 cm wide with entire margins. The undersurface of leaves is glabrous, often glaucous for most of the growing season. Football-shaped capsules are borne on erect pedicels; capsules are 8-17 mm long x 3.5-8 mm wide. Capsules are frequently densely covered with multicellular stipitate-glandular hairs; sometimes also sparsely unicellular-hairy. This species is scattered and occasional on the boulder outcrops and woodland edge along this portion of the Susquehanna River. Seed collected from 20 plants; approximately 80 to 100 fruits collected.
Collector(s):