46 FLORA OF WASHINGTON AND VICINITY. 



has been here adopted of testing such questions can be relied upon, this 

 southern leaning on the part of the Washington flora is clearly exhib- 

 ited in this table. In letting the eye follow columns 4 and 5 the differ- 

 ences are well marked in nearly all the groups and in most of the large 

 orders. These are what express statistically the essential character- 

 istics of the northern as contrasted with the southern flora. It is also 

 obvious that the figures iu column G will in most cases express the mean 

 between these two extremes. To obtain the true position of our flora, it 

 is necessary to observe toward which of these extremes it most nearly 

 approaches, and whether it falls on the northern or southern side of the 

 mean established by column G. In instituting this comparison we per- 

 ceive at the outset that iu the Poljpetalous Division it falls so far on 

 the southern side as to come within four-tenths of one jjer cent, of being 

 identical with the flora of the Southern States. In the Gamopetalce^ 

 however, it agrees quite closely with the flora of the Northern States, 

 so that iu the Bichlamydecv, as a whole, it coincides very well with the 

 mean for both sections. The Monochlamydca' agree better with those of 

 the Southern States, and the total Dicotyledons fall largely on the 

 southern side of the mean. The Monocotyledons also fall somewhat on* 

 the southern side, while the Gjmnosperms are below the mean which 

 here corresi^ouds with the southern flora. This leaves the total Phseno- 

 gams occupying an intermediate position. The Cryptogams are also 

 very nearly intermediate, though approaching the northern side. 



Considering next the relations of tlie large orders, we find that in the 

 Compositcv our flora is northern in aspect. In the Graminecv it is very 

 excex^tionally rich, surpassing all the larger areas and approaching that 

 of Essex County, Massachusetts. In the Cyperacea', which are pecu- 

 liarly typical for the puri)ose on account of being all indigenous in all 

 the floras, it does not corresx^oud at all either with the northern section 

 or with the average of both sections, but does agree very closely with 

 the exceptionally meager representations of the southern flora. The 

 Leguminosce are here northern in aspect, the Eosacece, like the Graminecc, 

 exceptionally rich, far exceeding either section, as is also the case with 

 the Labiatce and the Crucifenv. The ferns are northern in their degree 

 of representation, as are the Ranunculacece, while the Ericacece and 

 Scrophulariaceoc are southern. The Cupuliferw agahi are anomalous and 

 tower above all other floras. The LiUacece are southern, as are also the 

 Orchidacew. The Polygonacew are in excess and in so far southern in 

 aspect, while the Umbelllferce, also in excess, denote a northern inclina- 



