Diagnostic Characteristics
Geum is a genera of approximately 60 species, primarily of the north temperate zone, with Geum vernum a member of the monotypic subgenus Stylipus (Gleason, 1952). Identification can be confused with Geum canadense when vegetative, since the two species can occur together (New Jersey Department of Environmental Protection and Energy, 1993). However, G. vernum disperses seed in mid-June when G. canadense if first flowering. G. vernum can be distinguished by the absence of bractlets and stipitate fruiting head.
Habitat
From southern Ontario to Wisconsin, Iowa and southeast Kansas, extending to the east to New York, New Jersey, and Delaware, and reaching it's southern limit in North Carolina, Tennessee and Arkansas (Argus and Pryer, 1990). G. vernum is known to occur in rich loamy soil of wooded slopes, thickets, floodplains, and moist limestone ridges in rich woods.
G. vernum is locally common at the northernmost part of its range in Essex County, Ontario, where it is ranked S3 with 40 or 50 extant and 5 historical sites, in low moist clay woods. This county is highly agricultural and many of the remaining natural areas are threatened. It is rarer in the adjacent counties of Kent with 3 locations, Middlesex with 2 locations, and Lambton with approximately 6 locations (Oldham, pers. comm.).
In Michigan it was tracked as a special concern species until 1991 when it was delisted with at least nineteen occurrences. The species is considered fairly common (Penskas, pers. comm.). It occurs in the Washtenaw District in the southeast portion of the state in five counties (Voss, 1985).
The species continues to be common south of the Great Lakes, through Wisconsin, Indiana, Ohio, Illinois, and Missouri, where it is sometimes weedy in disturbed woods, and is not tracked by Heritage Programs. In east Kansas there are 45 extant and 5 historical occurrences in 15 counties (Freeman, pers. comm.). In Iowa, it is known only from historical records from four counties from 1928-1939, with no confirmed extant occurrences. It is classified as a special concern plant in Iowa (Pearson, pers. comm). In Pennsylvania it is not tracked, but there are over 50 historical records across the south part of the state (Wherry et al., 1979). The species is considered increasing in the west-central region (Kunsman, pers. comm.).
In Vermont it is known from a single population last seen 7-8 years ago in an overgrown weedy area adjacent to a pottery studio. When last visited, the site was cleaned up and the plant was not found. This species is not considered part of the natural flora of Vermont (Popp, pers. comm.).
G. vernum is rare in the eastern states of New York, New Jersey, and Delaware. In New York, the species is known from 7 historical locations and 3 current occurrences in widely scattered locations south of the Adirondacks (Young, pers. comm.). In New Jersey, there is one historical and seven extant locations (New Jersey Natural Heritage Program, 1993). The species appears to be increasing in the state, however, part of this may be due to better inventory of sites. After an initial assessment of the status in the state as adventitive (Britton, 1913) it has been recently reevaluated as native (Snyder, 1989). In Delaware, two extant occurrences exist in the northern portion of New Castle County in the piedmont (Delaware Natural Heritage Inventory, 1993).
In the southeast G. vernum becomes slightly more common. It is common in West Virginia to the west of the Alleghenies in moist woods and alluvial soil (Artz, 1961). In Virginia, it is present in 12 counties in the north and east, with several of the initial reported locations described by Artz (1961). It is endangered in North Carolina, with populations in the northwest portion of the state (Argus and Pryer, 1990). It is common in central and eastern Tennessee (White, 1982) with probably greater than 100 occurrences (Pyne, pers. comm.). In Kentucky, it is frequent in dry-mesic and mesic woodlands and openings on the Coastal Plain, Highland Rim, Knobs, and Bluegrass physiographic provinces. It is possibly less frequent in the Shawnee Hills and the Cumberland Mountains and the Appalacian Plateaus (Medly, 1993).
The southwest of the species range includes Oklahoma, northern Texas, and Arkansas. In Arkanses it is known from the northeast corner of the state in eleven counties (Smith, 1988).
Ecology
G. vernum is distinctive when in flower or fruit, and persists as a rosette of leaves during the rest of the year. It flowers early, from late April to mid May, fruiting in early May to early June. Seed dispersal is in the form of hooked akenes (Snyder, 1990). Not much detailed information is available on this species beyond descriptions of preferred habitat types and associated species at several extant locations.
The Washington Crossing State Park location is on the seepy bank of a streamlet draining into the Delaware (Snyder, 1990). At another location on a high bank of the Delaware it is frequent along a woods road growing in places with another endangered species, Hydrophyllum canadense. Another location occurs on the lawn outside the front door of a naturalist and plant collector, T. Gordon, who 9has visited locations of Geum vernum. The plant was probably dispersed to this location by the long beaks of the achenes attaching to his clothing (Snyder, 1990).
Individual populations tend to be large. At Washington Crossing Natural Area, New Jersey, up to 900 plants have been tentatively identified as G. vernum, where the population persists on the edges of a trail (New Jersey Department of Environmental Protection and Energy, 1993). G. vernum persists along a slope in greater numbers where the trailside vegetation has been trimmed, resulting in 30-50% overhead canopy cover. Approximately seven times as many individuals persist here than along another sloping section of the same trail, with a canopy cover of 50-75%. The population along each slope declines as the habitat becomes drier and flatter (New Jersey Department of Environmental Protection and Energy, 1993). The total number of individuals in New Jersey is estimated to be at least 5000 (New Jersey Natural Heritage Program, 1993).
Snyder (1989) reports Geum vernum was collected in New Jersey at a vague location listed as "Princeton" as early as 1885. It was later collected in 1914 and 1936, and then not again until 1986 (Snyder, 1989). It has been reported at seven locations in the state in recent years. At one location on the Southwest branch of Rancocas Creek, it occurred scattered over a mile or more of rich floodplain forest, growing with Betula nigra, Fagus grandifolia, Liriodendron tulipifera, and Acer negundo (Snyder, 1989). All known sites in New Jersey occur along river corridors of the Delaware River watershed. Populations are often in disturbed roadside sites and on wooded slopes near streams (New Jersey Department of Environmental Protection and Energy, 1993).
Only two populations are extant in Delaware. One population of 50-100 individuals flowering in 1991 persists in a grassy area along with Poa pratensis, Cardamine hirsuta, Taraxicum officinale, Trifolium repens, Erigeron philadelphia and Barbarea vulgaris on disturbed alluvium soil. This is considered a fluctuating population which may have been present for some time. Another population, with greater than 100 flowering genets, exists between the ruts in and along a lightly used old gravel road through a mature woods (Delaware Natural Heritage Inventory, 1991).
In Michigan, G. vernum is known from numerous locations, some of which have been described as follows: shrubby edge of cedar swamp, in road in oak-hickory woods on sandy soil, the base of a south-facing swamp between an elm swamp and a beech-maple woods, moist sloping woods near a river (Michigan Natural Features Inventory, 1991).
More detailed descriptions of two sites have been recorded (Michigan Natural Features Inventory, 1991). The first site was described as a wooded border along a creek with an overstory of Fraxinus spp., Tilia americana, Quercus alba, Q. rubra and Carya ovata. The understory was composed of Cercis canadensis, Ulmus rubra, Viburnum prunifolium and Zanthoxylum americanum. Another location of G. vernum was described as having an overstory of primarily Tilia americana, Ulmus americana, and Fraxinus pensylvanica, and an understory of 50% Ribes americanum. Approximately 60% of the ground cover was composed of Polygonum virginianum, Geum canadense and Sanicula gregaria (Michigan Natural Features Inventory, 1991).