|Plant Taxonomy (BIOL308) - Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; email@example.com; http://www.employees.csbsju.edu/ssaupe/|
Lab: Common Plants of the St. John's Prairie
Objectives: Upon completion of this field trip the student should be able to:
Before the arrival of European settlers, prairie was the primary vegetation type in western Minnesota. Roughly speaking, prairie would have been occurred to the south and west of an imaginary diagonal line drawn from the northwest corner of Minnesota to the southeast corner. To the causal observer, prairies can be "boring." However, upon closer examination, prairies have a wealth of species from the dominant grasses to the diverse forbs (non-grass herbaceous plants). In fact, it's not uncommon to find more than 300 species in a native Minnesota prairie.
Today we will visit the St. John's Arboretum prairie which is located on the north end of campus near the intersection of I-94 and Cty Rd 159. It was planted in 1991 (brief history of the St. John's prairie restoration project) and currently more than 250 species have been identified (St. John's Arboretum website). Our goal during lab will be to learn to identify some of the most common fall-flowering species.
The two most abundant taxa we will encounter are members of the Asteraceae (Sunflower family) and Poaceae (Grass family). The characteristic inflorescence (head) of the Asteraceae makes this family easy to identify, though individual genera and species can be more difficult. We should find several species of goldenrod (genus Solidago). Two particularly common species are the wand goldenrod (S. nemoralis) which has a more upright, spike-like cluster of heads and stiff goldenrod (S. rigida) that is characterized by its flat-topped cluster of heads and leaves that are covered with stiff hairs. Black-eyed Susan (Rudbeckia hirta), coneflower (Echinacea sp.) and gray-headed coneflower (Ratibida pinnata) are easy to recognize based on the distinctive disks at the center of each head that are surrounded by yellow or pinkish ray flowers. Plants in the genus Artemisia, such as sage (A. ludoviciana) are typically bluish-green in color and fragrant. It's not surprising that the flowers are wind-pollinated because they are relatively small and unassuming. There are several species of blazing star (Liatris sp.), all of which are easily recognized by their unbranched cluster of pink flowers. Traditionally, the genus Aster was comprised of a large number of species that typically bloomed in the late summer and autumn. In recent years, this group has been subdivided in many smaller genera. We will use the traditional name (Aster) for this group but be aware that it will change.
The grasses can be readily identified by the morphology of their flowering heads. Though a little more difficult, grasses can also be can be identified in their vegetative state. To do so, requires examining a variety of other characteristics. For example, big bluestem (Andropogon gerardii) has lower leaves that are covered with silky hairs and has a ligule that is about 1/8 and membranous whereas little bluestem (Schizachryium scoparium) has no hairs and a shorter ligule. Canada wildrye (Elymus canadensis) has clasping auricles with a short, collar-shaped ligule. The ligule of Indiangrass (Sorghastrum nutans) is divided somewhat like a claw hammer. Blue grama grass (Bouteloua gracilis) has a ligule comprised of a fringe of short hairs and grayish-green foliage. Sideoats grama (Bouteloa curtipendula) has glandular hairs along the margins of the leaf with short membranous ligules.
Assignment Due Today:
During today's lab we will visit the St. John's prairie 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.)
APIACEAE - Carrot Family
ASCLEPIADACEAE - Milkweed Family
ASTERACEAE (Compositae) - Sunflower Family
FABACEAE - Bean or Pulse Family
LAMIACEAE (Labiatae) - Mint Family
POACEAE - Grass Family
RANUNCULACEAE - Buttercup or Crowfoot Family
ROSACEAE - Rose Family
SAXIFRAGACEAE - Saxifrage Family
SCROPHULARIACEAE - Figwort Family
SOLANACEAE - Tomato Family
VERBENACEAE - Vervain Family
Sedivec & WT Barker. 1997. Selected North Dakota and Minnesota Range Plants. North Dakota State University of Agriculture and Applied Science & USDA. 270 pages. Jamestown, ND. Click here. The vegetation map image above was borrowed from this web site.
St. John's Arboretum website - St. John's Prairie
Prairie Restoration at St. John's - presentation to Master Gardener's conference (Summer 2004)
Online keys to the grasses of Minnesota (National Resources Conservation Services, National Plant Data Center)
Fassett, NC. Grasses of Wisconsin. University of Wisconsin Press, Madison
Vance, FR, et al. 1884. Wildflowers of the Northern Great Plains. University of Minnesota Press, Minneapolis.
Ladd, D. 1995. Tallgrass Prairie Wildflowers. Falcon Press, Helena, MT
Moyle, JB & EW Moyle. 2001. Northland Wildflowers. Revised edition. University of Minnesota Press, Minneapolis.
09/25/2008 / � Copyright by SG