Life history

Species overview

Sycamore (Platanus occidentalis), a Wisconsin Special Concern plant, is found in floodplain forests. Blooming occurs throughout May; fruiting occurs early June through early September. This species can be identified year-round.

Synonyms: Platanus glabrata, Platanus occidentalis f. attenuata, Platanus occidentalis var. glabrata

Identification

• Distinguishing characteristics: Although sycamore leaves may be similar to those of various maple species (Acer spp.), the former have shallower lobes and are arranged alternately instead of oppositely.
• Flower characteristics: Flowers very small, solitary, with long stems.
• Fruit characteristics: Achenes many on spherical receptacles; seeds of sun flower-like; seed pod 7 to 8 mm in length and with hairs below the pod that are nearly as long as the pod itself.
• Leaf characteristics: Alternate, broadly 3- to 5-lobed, sharply toothed and mostly kidney-shaped in outline.

Phenology

• Blooming phenology: throughout May
• Fruiting phenology: early June through early September
• Optimum time to identify: This species can be identified year-round

Other

• Growth form: Tree
• Vegetative reproduction:
• Life cycle: Perennial
• Comments: Associated Species: Acer saccharinum, Betula nigra, Ulmus americana, Celtis occidentalis, Fraxinus pennsylvanica, Gleditsia triacanthos, Crataegus spp.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Sycamore (Platanus occidentalis). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

• Habitat description: Found in floodplain forests.
• Soils: Moist to wet, alluvial soils.

Natural communities

This table lists the natural communities that are associated with Sycamore. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Sycamore. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

• Avoid broadcast spraying of herbicides; use care with spot spraying.
• Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
• Avoid site preparation that heavily disturbs herbaceous ground layer and soil; these include bulldozing and furrowing, as well as grubbing and stump removal.
• Avoid locating landings, staging areas, or access routes on or near known populations.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

• Minimize disturbance to hydrology, including soil disturbance from rutting.

Other resources

Links to additional Sycamore information

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use