ON Tirr. CH AKACTKltlSTK.'.? OF Till; NOUTII AMKIUCAN II.OUA. 561 



the 



|Kui-ope 

 ibor of 

 absent 

 liffeving 

 'ovnu'd, 

 |r north 

 poiiln- 

 lutially 

 ments.) 

 presen- 

 -1.42"; 

 Isentinf? 

 .r coast 

 .ctaally 

 ligfuoiiiii- 

 of the 

 of this 

 ihem I 



\'t!ckon sarracenia (of which the only oxlra-Xorth American ropresontativo 

 is tropical- Americun), the raelastoniaci'a', represented by rhexia; passiflora 

 (onr species being herbaceous), a few representatives of loasacca) and 

 tnrncraccte, also of hydrophyllacesv) ; our two genera of burmanniacea) ; 

 three genera of ha'modoracciu ; tilhindsia in bromeliacca) ; two genera of 

 poiiledcriacca? ; two of commeiynucea!-, the outlying mayaca Jind xyris, 

 and three genera of criocaulooacciv;. [ do not forget that one of our 

 species of eriocaulon occurs on the west coast of Ireland and in Skyo, 

 wonderfully out of place, though on this side of the Atlantic it reaches 

 Xewfoundland. It may be a survival in the Old World; but it is more 

 probably of chance introduction. 



The other set of extra-European types, characteristic of the Atlantic 

 North American flora, is very notable. According to a view which I have 

 nuich and for a long while insisted on, it may bo said to represent a 

 certain portion of the once rather uniform, flora of the arctic and less 

 boreal zone, from the late tertiary down to the incoming of the glacial 

 ])eriod, and which, brought down to our lower latitudes by the gradual 

 refrigeration, has been preserved hero in eastern Xorth America and in 

 the corresponding parts of Asia, but was lost to Europe. I need not re- 

 capitulate the evidence upon which this now generally accepted doctrine 

 was founded ; and to enumerate the plants which testify in its favour 

 would amount to an enumeration of the greater part of the genera or 

 snbovdiiiple groups of jdants which distinguish our Atlantic flora from 

 that of Europe. The evidence, in brief, is that the plants in question, or 

 their moderately difl'erentiated representatives, still co-exist in the flora of 

 oasteru Xorth America and that of the Chino-Japanese region, the climates 

 and conditions of which are very simihar; and that the fossilised repre- 

 sentatives of many of them have been brought to light in the late tertiary 

 de])osits of the arctic zone wherever explored. In mentioning some of 

 the plants of this category I include the magnolias, although there are no 

 nearly identical species, but there is a seemingly identical liriodendron in 

 China, and the schizandras and illiciums are divided between the two 

 floras; and I put into the list menispermum, of which the only other 

 species is eastern Siberian, and is hardly distinguishable from ours. When 

 you cill to mind the series of wholly extra-European types which are 

 identically or approximately repi'esonted in the eastern North American 

 and in the eastern Asiatic temperate floras, such as trautvetteria and 

 hydrastis in ranunculacca) ; caulophyllum, diphylleia, jeH'ersonia and 

 podo[)hyllum in berberidea; ; brasenia and nelumbium in nymphaiacea) ; 

 stylophorum in papavcracea' ; stuartia and gordonia in ternatromiaceoa ; 

 the equivalent species of xanthoxylnm, the equivalent and identical species 

 of vitis, and of the poisonous species of rhus (one, if not both, of which 

 you may meet with in every botanical excursion, and which it will be safer 

 not to handle) ; the horse-chestnuts, here called buckeyes ; the negundo, 

 a peculiar off-shoot of the maple tribe ; when you consider that almost 

 every one of the peculiar leguminous trees mentioned as charac*^eristic of 

 our flora is represented by a species in China or Manchuria or Japan, and 

 so of some herbaceous leguminoste ; when you remember that the peculiar 

 small order of which calycanthus is the principal type has its other repre- 

 sentative in the same region ; that the species of philadelphus, or 

 hydrangea, of itea, astilbe, hamamelis, diervilla, triostcum, mitchella, 

 v.hich carpets the ground under evergreen woods, chiogenes creeping 

 over the shaded bogs; cpigaia, choicest woodland flower of early spring; 



1884. ' 



■I 



. 



