90 



By way of introduction the status of the flora from a qualitative 

 viewpoint may be briefly summarized. Exclusive of the thallo- 

 phytes, 1,949 indigenous species of plants have been recorded 

 from Connecticut. Of these the bryophytes include 463 (liver- 

 worts 134, mosses 329), the pteridophytes 74, and the spermato- 

 phytes 1,412 (gymnosperms 13, monocotyledons 496, dicotyledons 

 903). Besides the native element there is a large and constantly 

 increasing number of spermatophytes which have been variously 

 introduced and which in many cases have become thoroughly 

 established. Upward of 460 such aliens are now known, but 

 while qualitatively and even quantitatively abundant, they may 

 largely be disregarded in the present discussion, since they serve 

 to complicate rather than simplify matters. Nearly 70 per cent 

 of the indigenous plants are endemic to North America, the 

 remaining 30 per cent being in large part common to Europe 

 or Asia or both. It is instructive to note, however, how vastly 

 the relative proportions of endemic and extra-continental species 

 vary among and within the great divisions and subdivisions of 

 the plant kingdom. For while less than 20 per cent of the local 

 bryophytes are endemic, and of the pteridophytes hardly 50 

 per cent, fully 92 per cent of the gymnosperms (Juniperus 

 communis seems to be the sole exception), 80 per cent of the 

 monocotyledons, and nearly 90 per cent of the dicotyledons are 

 not known to occur outside of this continent. Furthermore, 

 among the pteridophytes, for example, only 30 per cent of the 

 homosporous species but nearly 80 per cent of the heterosporous 

 species are endemic; and similarly among the dicotyledons, to 

 select specific cases, it would seem that while nearly 30 per cent 

 of the 37 local Ranunculaceae are extra-continental in range, 

 all but about 2 per cent of the more than 160 Compositae are 

 endemic. The general assertion may be made that in the more 

 primitive groups of plants the species tend to have a wider 

 range than in the more advanced groups; or, to use a different 

 phraseology, that species in groups of comparatively recent 

 evolutionary derivation are far more restricted in range than 

 species in groups of more ancient origin. An examination of the 

 intra-continental ranges of the various species which comprise 



