4 04 IOWA ACADEMY OF SCIENCE 



group indicating common ancestry. The second group is some- 

 what scattered near the middle of the west side of the area. None 

 of these trees occur in the upper half of the forested area, and 

 none of them occur on the river bottom. They appear to seek 

 the medium conditions as to moisture and shelter, and the scatter- 

 ed ones are apparently aviveetant. 



There are six raspberry bushes (Plate XIII. figure XI i distri- 

 buted, three of them in the upper section, and three in the middle, 

 of the lower part of the wooded bluff face in such a way as to 

 indicate that they are planted by birds. 



Thirty-three buck bushes ( Plate XIII. figure XII) occur, dis- 

 tributed in three groups, one group, in two parts, near the upper 

 limit of tree growth, another near the middle of the west side, 

 the third a short distance above the foot of the bluff. This dis- 

 tribution may be taken to show ability in this plant to adapt itself 

 to considerable ranges of humidity and exposure, and. in the 

 lower groups at least, it is apparently the work of birds. The 

 bush does not occur at all on the river bottom where the condi- 

 tions affecting plant life are such as to require the ability to 

 handle much moisture. 



Six hundred eighty-five hop hornbeam trees (Plate XIII. figure 

 XIII i appear in the tract. Xone of these trees are on the river 

 bottom, and the greater part of them are grouped in close associa- 

 tions on the lower half of the bluff face. Some of these groups in- 

 dicate a distribution from a common center, a parent tree. Vacant 

 areas among them are to be attributed to over-crowding by other 

 trees. Some of these trees are found in the upper part of the 

 forest, and one small group occurs near the upper forest limit, 

 showing that they are able to adapt themselves when necessary 

 to considerable variation in conditions. Xone of these trees are 

 large, as large size would be impossible because of their crowded 

 manner of growth. 



Twenty-four Kentucky coffee bean trees (Plate XIII. figure 

 XIV. occur on the bluff face not far from its foot. This tree 

 grows to considerable size and in this place has good protection 

 and plenty of moisture, but is unable to survive the very wet 

 conditions of the river flat. 



Only one red cedar grows in this piece of timber ('Plate XIV, 

 figure XX . and it is a small one of only one-half inch diameter, 

 found in an opening among the bass woods and hop hornbeams, 



