168 



counties in the State have been worked with such persistence and with such 

 painstaking accuracy. Others of the species are doubtless restricted to the 

 rich alluvial soils of the lower Wabash Valley. 



To these might be added a small group showing a distribution so 

 unconnected as to be extremely difficult of explanation. An instance is 

 found in Pin us Strobus L.. which is found in Lake. Porter and Laporte. 

 extreme northwestern counties : Warren and Montgomery, western-central 

 counties; and in Clark in the southeastern part of the State. Its occur- 

 rence in the northwestern counties affords no difficulty ; tbe western- 

 central location might be explained as a continuation of the former area : 

 but the recurrence of the species in Clark County on the Ohio River in the 

 eastern part of the State furnishes a difficult problem. In the case, also, of 

 Cratcegus coccinea L., we find equally unrelated areas, this species being 

 reported only from Noble and Steuben, extreme northeastern counties, and 

 Floyd, a southern county on the Ohio River. The genus Crataegus, how- 

 ever, presents such difficulties in the discrimination of species that the case 

 just cited may possibly be due to lack of accuracy in determination. 



The species limited to Knox. Gibson and Posey counties or to some 

 part of the area are as follows : 



Taxodium distich urn (L.) L. C. Richards. 



Hicoria Pecan (Marshall) Britton. 



Quercus lyrata Walter. 



Quercus Miehauxii Nuttall. 



Quercus falcata Michaux. 



Geltis mississippicitsis Bosc. 



Cratcegus mridis Linnams. 



Cratcegus nitida (Engelmanni Sargent. 



Gleditsia aquatica Marshall. 



Ilex decidua Walter. 



Forestiertt acuminata (Michaux i Poinet. 



In addition to these species, which seem strictly limited to the region 

 named, two others have been reported from a single additional county : 

 Gatalpa speciosa Warder. Gibson. Knox, Posey and Vigo. 

 Fraxinus Miehauxii Britton. Gibson, Posey and Marion. 



The Bald cypress (Taxodium) is a southern swamp form, which finds 

 in the Indiana locations its extreme northeastern limits. In Indiana it is 



