70 



the groups covered in the volume before us, the number of species 

 in the former is more than three fourths as great as in the latter. 

 So closely does the flora of Abrams follow that of Britton and 

 Brown in arrangement, and in the concepts of families, genera, 

 and species, that it is a very simple matter to compare the two 

 works group by group, and ascertain the relationships of the 

 two floras. In our comparison we have used the second edition 

 of Britton and Brown. 



Thus we find that in the coast flora there are about four fifths 

 as many ferns and fern-allies as in the northeastern flora. Only 

 a few genera are notably larger, such as Cheilanthes, Pellaea, 

 Notholaena, and Selaginella, while others, such as Dryopteris, 

 Asplenium and Lycopodium, are much smaller. On the other 

 hand, the western species of gymnosperms are almost twice as 

 numerous as the northeastern ones. 



There are nearly as many kinds of western grasses as of 

 northeastern ones, but the percentages differ greatly in different 

 tribes. For instance, in Paniceae there are 27 Pacific species 

 and 120 northeastern ones, while in Hordeae there are 48 Pacific 

 species and only 39 northeastern ones. In other groups, grass 

 genera more largely represented in the coast flora are Stipa, 

 Agrostis, Calamagrostis, Bouteloua, Melica, Poa, Festuca, and 

 Bromus. The coast Cyperaceae are less than two thirds as 

 numerous as the northeastern ones, the great genus Carex being 

 very slightly larger in proportion than the other genera, namely, 

 167 to 242. One whole series of monocotyledonous families 

 represented in the northeastern flora (Mayacaceae, X^'ridaceae, 

 Eriocaulaceae, Bromeliaceae, and Commelinaceae) is wholly 

 without representation in the western area, but these are all 

 characteristically tropical groups, represented to the northward 

 by only a few outlying species. 



Among the higher monocotyledons there are some striking 

 contrasts between the two floras. In the Melanthaceae, for 

 instance, the western shows 6 genera and 17 species, the eastern 

 14 genera and 20 species, yet only one species (Veratrum viride) 

 is common to the two; Amaryllidaceae comprises one genus with 

 4 species in the western, and 7 genera, each with a single species, 

 in the eastern. On the other hand, there are 9 genera and 21 

 species of Convallariaceae in the western, and 11 genera and 28 

 species in the eastern, no less than 5 of the genera showing the 



