COMMON NAME

Cup plant
cupleaf rosinweed
squarestem rosinweed

FULL SCIENTIFIC NAME

Silphium perfoliatum L.

FAMILY NAME COMMON

Aster family

FAMILY SCIENTIFIC NAME

Silphium perfoliatum

IMAGES

Flower and Opposite Leaves	Flower close-up	Incursion
Cross-section of stem and clasping leaves	Close-up of Seed Head	Seed Heads

NOMENCLATURE/SYNONYMS

Synonyms: None

DESCRIPTION

Botanical Glossary

Silphium perfoliatum is an herbaceous perennial that can grow from 1-2.5 m (3.3-8.2 ft.) in height. The stem of this plant is square and glabrous. The oppositely arranged leaves are ovate or deltoid-ovate in shape and have a coarsely toothed margin. They measure 15-30 cm (6-12 in.) long and 10-20 cm (4-8 in.) wide. The bases of the opposite leaves are fused together around the stem, forming a "cup" (and giving the plant its common name). This plant blooms from July to September, and the yellow flower heads can be numerous. The flower heades measure 1.5-4 cm (0.5-1.5 in.) across and have 20-30 rays. The achenes are gray to black, oblong, flat and notched at one end. They ripen from late September until frost. Page References Bailey 996, Fernald 1476, Gleason & Cronquist 546, Holmgren 512, Magee & Ahles 998, Newcomb 392, Peterson & McKenny 184. See reference section below for full citations.

SIMILAR SPECIES

Helianthus spp. (Sunflower) The flowers of Helianthus species look similar, but they do not have the cup-forming leaf bases that Silphium perfoliatum does.

REPRODUCTIVE/DISPERSAL MECHANISMS

Silphium perfoliatum reproduces primarily by means of seed that disperse mechanically. Water often moves the seeds over longer distances.

DISTRIBUTION

Silphium perfoliatum is native to the North America, from southern Ontario to North Dakota, south to North Carolina, Mississippi, Louisiana and Oklahoma. It has extended its range into New England, where it has been reported from Maine, Vermont, Massachusetts and Connecticut.

HISTORY OF INTRODUCTION IN NEW ENGLAND

Silphium perfoliatum is native to the mid-western and southeastern United States, and was likely introduced into New England via intentional plantings. From these intentional plantings, it has spread into less managed areas.

HABITATS IN NEW ENGLAND

In its native habitat, Silphium perfoliatum is found in moist regions, such as along prairie streams. In New England it can be found along water courses and open meadows.

THREATS

Since Silphium perfoliatum is native to parts of the United States, its planting as a "native plant" in New England has been encouraged. Due to its size, it is occasionally marketed as a "living fence". However, in New England it has exhibited an invasive tendency. It can form large stands that crowd out native New England vegetation.

MANAGEMENT LINKS

DOCUMENTATION NEEDS

Documentation required: A photograph of the perfoliate leaves with stem.
Best time for documentation: Summer, fall.

ADDITIONAL INFORMATION

Integrated Taxonomic Information System
Taxonomic information

PLANTS Database
General information and map

Weeds of the North Central States
Line drawing and description

USDA-NRCS
Fact sheet

Bailey, L.H. 1949. Manual of Cultivated Plants. Macmillan, New York.

Fernald, M.L.  1950.  Gray's Manual of Botany 8th edition.  American Book Company, New York.

Gleason, H.A. 1952. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada. Macmillan Publishing Co., Inc. New York.

Gleason, H.A. and A.C. Cronquist.  1991.  Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. 2nd ed.  New York Botanical Garden, Bronx, New York.

Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual.  New York Botanical Garden, Bronx, New York.

Magee, D.W and H.E. Ahles. 1999.  Flora of the Northeast. University of Massachusetts Press, Amherst.

Newcomb, N. 1977.  Newcomb's Wildflower Guide.  Little Brown, Boston.

Peterson, R.T. and M. McKenny. 1968. A field Guide to Wildflowers of Northeastern and North-central North America.  Houghton Mifflin, Boston.

USDA, NRCS.  2001.  The PLANTS Database, Version 3.1. (http://plants.usda.gov).  National Plant Data Center, Baton Rouge, LA 70874-4490 USA.