1128 Some Habitat and Distribution Terms Used 



Rivers. See streams. 



Rivulet. See streams. 



Roadsides. This term refers to the right-of-way of all kinds of public thoroughfares 

 used by vehicles. 



Shore. The margin adjacent to lakes, ponds, sloughs, and streams. 



Sinkhole. A funnel-shaped cavity in the earth's surface made by the dissolving of 

 the underlying limestone. The cavity varies in size from less than an eighth to five 

 acres. Sinkholes are frequent to common in most of the limestone area of the un- 

 glaciated region. The water in them varies in depth up to several feet, depending 

 upon the amount of rainfall and the seepage. I have never seen any vegetation in 

 them when they are located in deep woodland, doubtless because the decay of many 

 leaves prevent it. Those in fields are disturbed more or less by stock which destroys 

 much of their vegetation. Over a period of many years I have made a list of plants 

 I have seen or collected in them and it is a large and variable one. All are usually 

 surrounded more or less with Eleocharis and often Sagittarius, Junci, and Lophoto- 

 carpits calycinus. In the deep parts Potamogeton is often found. Constant filling in 

 from the washing of the surrounding slopes frequently contaminates the water so 

 that vegetation will not thrive. 



Slough. A slough is an elongated basin filled with water, rarely exceeding a depth of 

 six feet. Sloughs are remnants of old river channels that have not been filled by 

 sedimentation and are usually short, although a few are about a mile long. They 

 may be divided into high and low sloughs. Those that frequently overflow are 

 usually devoid of vegetation other than spatterdock and have little or no vegetation 

 on their banks. High sloughs are those that do not annually overflow such as Half 

 Moon Pond which has both spatterdock and waterlilies and vegetation on its banks. 

 Bayou lakes have the same origin, but are more circular in shape. Our most notable 

 example is Hovey Lake in Posey County. For want of a better name I am calling 

 also the water channels between the dunes near Lake Michigan sloughs. 



Soil. The soft outer surface of the earth composed of minute particles of various 

 rocks, organic matter, and solutes. This soft envelope or any part of it is called soil 

 (not ground) when a relation between it and plants is expressed. 



Spring. The discharge of water from a subterranean stream forms a spring. The 

 volume discharged may be of sufficient size to form a small stream like Donaldson 

 Cave or the volume may be reduced to form a pool and a small rivulet. Some 

 springs never reach the surface, but discharge below the surface, their water 

 escaping as seepage. These hidden springs are most frequent about lakes and along 

 rivers, forming springy areas which are erroneously called boggy places if they 

 discharge in mineral soil. The water of a springy place differs from the stagnant 

 water of a swamp. 



Springy areas. See spring. 



Stone quarry. A cavity made in the surface of the earth for the purpose of getting 

 stone for highways and building purposes. If they fill with water they usually have 

 no soil on their borders except at their outlet so they can not support vegetation. I 

 have seen Potamogeton in several, but do not recall any other species except cat- 

 tails. 



Streams. A stream is the generic term used to denote a volume of water moving from 

 one point to another, usually by the force of gravity. The volume of moving water 

 may vary greatly. The largest surface volumes are known as rivers, and these may 

 have many tributaries which in turn are usually known as rivers. Streams of a 

 size less than that of a river are known as creeks, branches, forks, and rivulets. 

 The volume of water a stream carries varies from flood to low water stages. The 

 channels of most streams in an early geologic time were much wider than now as 

 shown by wide intervening valleys between the old terrace banks. Banks of streams 

 include the area at the top of the channel as far back as quantity of light and 

 moisture differentiates the vegetation, and all the slope of the channel from the 

 top to the bed of the stream. The common meaning of a bank is the top and 

 slope of the channel from high water mark to the bed of the stream. The term is 

 often subdivided as top of the bank, upper or lower slope, and muddy base above or 



