Illinois Beach State Park (east of Zion, Illinois). This should 

 be visited in late spring — around Memorial Day is best. The 

 area is more of a prairie park. Prepare for cold weather, even in 

 late May, as the northeast winds off the lake can be quite 

 uncomfortable. The area near the lake is dominated by a 

 scrubby black-oak forest, but the prairie areas west of this for- 

 est are beautiful in late May and early June. Sand dunes are not 

 high here, because the dominant westerly and northwesterly 

 winds are blowing from the land out over the water. (In Indi- 

 ana and Michigan these same winds help to accumulate sand 

 from Lake Michigan onto the nearby shores. ) 



Microclimatic conditions influence our local area signifi- 

 cantly, and an interesting project is to study our tree distribu- 

 tion as affected by Lake Michigan and by local winds, rainfall, 

 and snowfall. For example, southern trees (sassafras, papaw, 

 sour gum, and flowering dogwood) are found in the Indiana 

 dunes and commonly in southwestern Michigan, yet are hard- 

 ly ever found in Lake County, Illinois, or in adjacent Wiscon- 

 sin. Interesting exceptions include the sour gum, which 

 occurs in Kenosha County, Wisconsin — the only place in the 

 entire state! Sassafras formerly occurred in the same county, 

 but is now being exterminated in Wisconsin. I remember a 

 sassafras colony of three trees in the area near Lake Michigan 

 adjacent to Kenilworth and Wilmette, but this has been gone 

 for many years. Sassafras still occurs wild in southern Cook 

 County. Papaw does get to southern Cook County and south- 

 ern Du Page County — quite a contrast to its abundance much 

 farther north in Michigan. Perhaps one can draw from all this 

 the reasons why we are able to grow abundant crops of peaches 

 and sweet cherries in southwestern Michigan, but not in Wis- 

 consin directly across the lake. 



Some of the more interesting wildflowers of spring are 

 discussed below, the woodland species first and prairie species 

 last. 



May flowers m Morton Arboretum. Pink-streaked white flowers are spring beauty 



(Claytonia virginica). Also shown are the blue violet (Viola papilionacea) and 



the yellow violet (Viola pensylvanica). Photo by John Kolar. 



# Spring Beauty (Claytonia virginica) 

 Purslane Family (Portulacaceae) 



This is probably the most abundant of our native woodland 

 wildflowers. It is a perennial which possesses an ample storage 

 root, giving it the ability to get an early start the following 

 spring. It also can stand quite a bit of abuse. The ultimate 

 example of such abuse may be observed when wooded property 

 is acquired and the oak trees are allowed to stand, but the rest 

 of the area is made into lawn. The spring beauty is usually the 

 only wildflower to remain, and it forms dense stands compet- 

 ing with the grass, often in circular patches which follow the 

 contours of the oak trees above. It occurs in almost every 

 wooded area in the Chicago region, but the greatest abun- 

 dance is on the Illinois side of the lake. Typical associates 

 include the white trout lily, white oak, hepatica, May apple, 

 and woodland phlox. 



* Violets (Viola spp.) 

 Violet Family (Violaceae) 



Our spring woodlands contain a number of interesting violets, 

 some very closely related to each other. These include the 

 common blue violet, Viola papilionacea (with smooth foliage) 

 and the hairy wood violet, Viola sororia (with hairy foliage). 

 There are also two yellow violets, Viola pensylvanica — also 

 known as Viola eriocarpa — with relatively smooth stems, and 

 Viola pubescens, with definitely hairy stems. Unfortunately, in 

 both of these groups intermediate specimens occur which can 

 be perplexing. In the meantime, many areas of dune land- 

 scapes become attractive with the beautiful blossoms of the 

 bird's foot violet, Viola pedata. One of the most unusual violets 

 occurs in the beech-maple forest at Warren Woods, and is 

 known as the long-spurred violet, Viola rostrata. As the com- 

 mon name implies, the floral spur which is characteristic of 

 violets as a group is considerably longer in this species than is 

 the case with our other common violets. 



12 



Environmental Field Trips 



to sites discussed in 



"Spring Wild£lowers ,, 



Field Museum offers a variety of environmental field trips in May-June and September- 

 October. The trips are designed for family groups and adult groups and are led by local 

 scholars and naturalists, including Field Museum staff. This spring's schedule features 

 adult trips to three of the areas discussed in this article: 



Starved Rock State Park — Sunday, May 4 



Indiana Dunes State Park — Sunday, June 1 



Morton Arboretum — Sunday, June 22 



Please call 322-8855 for additional information or to request a field trip brochure. 



