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FINDING THE PARASITIC DODDER

While conducting a vegetative cover survey of Mount Stewart Marsh, Roseamry Curley and I discovered a string-like orange plant entwined around a number of species of plants on the marsh. The plant proved to be the Common (or Swamp) Dodder (Cuscuta gronovii). Dodder is a

unique plant with an orange or reddish coloured stem. There are no true leaves but instead the plant has tiny scales. The flowers are white or cream coloured and produce a large amount of seeds. Most amazing is the parasitic nature of the plant.

The seeds of the Dodder germinate into plants without seed leaves and the young parasite must find a host to wind itself around within a limited period of time or it will die. If the plant successfully finds a host, it develops numerous finger-like projections spaced along its stem. These suckers penetrate the host plant and through these the Dodder feeds. At Mount Stewart, Dodder was found parasitizing Spotted Touch-me—not (Impatiens capensis), Aster (Aster novi-belgii), Morning-glory (Convolvules sepium) and some of the marsh grasses. Eventually the host plant will be robbed of life, as was the case with many of the plants that we saw.. Once the Dodder becomes established on its host it loses all contact with the soil.

Dodder is a member of the Bindweed family (Convolvulaceae) of which

the Morning-glory belongs. There are twelve species of Dodder in

North America, the most common species being the Common Dodder, the Field Dodder (Cuscuta campestris), the Clover Dodder (Cuscuta epithymum) and (Cuscuta umbrosa). Some of the Dodders can prove to be pest plants, such as the last mentioned which parasitizes agricultural

crops in Manitoba and Saskatchewan.

Dodder is not included in the species lists prepared for the Island

by Hurst (1933) or Erskine (1960). It is, however, shown on the range map for P.E.I. in The Flora of Nova Scotia (Roland and Smith, 1969). The Common Dodder is native to Canada (Frankton and Mulligan, 1970; and Roland and Smith, 1969).

References Erskine, A.J., 1960. The Plants of Prince Edward Island, Publ. 1088, Canada Department of Agriculture, 270 pp.

Frankton, and A. Mulligan, 1970.‘ Weeds of Canada, Canada Department of Agriculture, 217 pp.

Hurst, Blyth Sr., 1933. Flowering Plants and Ferns of Prince Edward Island, Reprinted from Transactions of the Royal Canadian In- stitute. Vol. XIX (2): 251-271. University of Toronto Press.

Peterson, T. and McKenny, 1968. A Field Guide to Wildflowers of Northeastern and North-centra1.North America. Houghton Mifflin Co., Boston, 420 pp.

Roland, A.E. and E.C. Smith, 1969. The Flora of Nova Scotia, The Nova Scotia Museum, Halifax, 746 pp.

Gail Curry South Melville

SANDING IN BRANT?

No Brant have been hunted on P.E.I. in Spring since the Migratory Bird Convention Act was declared law August 16, 1916. Several old gunners, recalling spring shoots, told me that before the Brant migrated north in

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