Objectives:  Upon completion of this field trip the student should be able to:

1. describe some adaptation plants use for survival in aquatic habitats
2. identify approximately 30 species of aquatic plants common in the lakes and wetlands at St. John's

Introduction:
   The many lakes, marshes, and wet meadows on our campuses provide habitat for a rich flora of aquatic plants.   Plants of open water, like lakes and ponds, can exhibit a variety of growth forms.  For example, some species: (1) float on the surface of the water and are not rooted in the substrate (e.g., Spirodela, Lemna minor, Wolfia); (2) float submerged under the water and are not rooted in the substrate (e.g., Lemna trisulca, Utricularia, Ceratophyllum); (3) have leaves that float on the surface but are rooted in the substrate (e.g., Brasenia schreiberi, Nuphar variegatum, Nymphaea odorata; (4) are completely submerged (except for the flowering shoot) and are rooted (e.g., Elodea, Potamogeton, Myriophyllum, Vallisneria, Ranunculus flabellaris); and (5) dimorphic plants with both submerged and floating leaves and are rooted (e.g., Potamogeton). 

    Some common adaptations exhibited by species of open water include: (1) thin, highly-dissected leaves; (2) no cuticle; (3) no roots; (4) stomata on the upper sides of leaves; (5) reproduction by fragmentation; and (f) flowers produced above or on the water surface for pollination (e.g., Utricularia). In a few species (e.g., Vallisneria) the male flowers are produced underwater but the flowers and/or pollen floats to the surface for pollination.

    Plants of marshes are typically emergent (rooted in the substrate and emerge above the surface of the water). These plants must be adapted to having their roots permanently or seasonally flooded. Marshes are among the most productive and provide floodwater retention, habitat for wildlife, and protect shorelines from erosion. Some common plants in these areas include cattails (Typha sp.) and bulrush (Scirpus sp.)

    Many species of wetland plants occur on the campus of St. John's University. Some of these are 'obligate' wetland species such as Potamogeton, Typha) that only grow in wet areas, while others are 'facultative' wetland species such as Fraxinus nigra, Eupatorium perfoliatum, Vitis riparia) that will grow in wet or drier areas.  The purpose of today's lab is to introduce you to some of the more common wetland species that occur in central Minnesota.

Assignment Due Today:

• Wear clothing appropriate for going into the field and bring water, sunblock and bug repellent
• Field quiz #4

Lab Activity
    During today's lab we will visit the St. John's lake to find the plants in the PTK list below.  We will go out rain or shine so dress appropriately.  Out in the field I will describe the key characteristics of these species and provide other information (edibility, uses, etc.) as appropriate.   You will may want to bring a notebook and pen to take notes about each species that we find. 

Plants to Know:  (We will locate the following species that will be "fair game" on the PTK quiz/exam.  Other species may also be included.)

 References: