398 



IOWA ACADEMY OF SCIENCE 



where the Big Sioux river flows in a westerly direction for 

 several miles at the foot of a series of high bluffs. The north 

 face of these bluffs is heavily timbered, and is the subject of 

 this paper. 



The particular locality chosen was on the south bank of the 

 Big Sioux river at a point known as Syverud Bluff, where the 

 high hills on the south side of the river rise to a height of about 

 180 feet above the stream. This maximum height is attained 

 at a distance of about one-fourth of a mile south of the river. 

 A typical strip of the timbered land extending from the river 

 south to the bare prairie at the top of the bluff was selected for 

 the survey. This strip was 145 feet wide. The woodland chosen 

 was divided into quadrats, and a careful census made of all 

 trees and shrubs, the size of each being taken, and a special 

 effort made to locate each one accurately. The charts accom- 

 panying this report indicate the localities of growth. The list 

 of trees, vines, and shrubs is as shown in the following table, 

 and the accompanying graph, figure 46., indicates proportions. 



Name of Plant 



No. OF 

 Speci- 

 mens 



I. Acer saccharinum L. (soft maple) 



II. Ulmus americana L. (American elm) 



III. Salix nigra Marsh (black willow) 



IV. Acer negundo L. (box elder) 



V. Vitis vulpina L. (wild grape) 



VI. Fraxinus pennsylvanica var. lanceolata 



(Birk) Sarg. (green ash) 



VII. Tilia americana L. (Basswood) 



VIII. Ribes Cynosbati L. (goose berry) 



IX. Alnus sp. (alder) 



X. Prunus virginiana L. (choke cherry) 



XI. Rubus idaeus var. aculeatissimus (C. A. 



Mey) Regel & Tiling (raspberry) 



XII. Symphoricarpos occidentalis- Moench (buck 

 bush ) 



XIII. Ostrya virginiana (Mill) K. Koch (Ameri 



can hop hornbeam) 



XIV. Gymnocladus dioica (L.) Koch (Kentucky 



coffee tree) 



XV. Quercus macrocarpa Michx. (bur oak) .... 

 XVI. Crataegus mollis (L. & G.) Scheels (haw- 

 thorn) 



XVII. Celastrus scandens L. (climbing bitter 



sweet) 



XVIII. Prunus americana Marsh (wild plum) .... 



XIX. Juglans nigra L. (black walnut) 



XX. Juniperus virginiana L. (red cedar) 



Total 



40 



440 



117 



9 



13 



43 



•1184 



382 



8 



16 



6 



33 



685 



24 

 190 



50 



5 



148 



5 



1 



3399 



Per Cent 



1. + 



12. + 



3. + 

 •2 + 

 •3 + 



1. + 



34. + 



11. + 



•2 + 



•4 + 



•1 + 



• 9 + 



20. + 



•7 + 

 5. + 



1- + 



•1 + 



4. + 

 •1 + 

 .02+ 



100. 



