MERIDIANS OP DISTRIBUTION. 



4-; 



This diagram appears to prove 



(1) that there are four meridians of distribut 



province to the American, European, Sibe 



passing 



ipectivelv 



i 



from the Circumpol 



and Japanese pro vine 



(2) that there 



extension of the Amer 



or 



European merid 



and 



■ 



(3) that the Siberian meridian is projected into the Caucasus 



At the same time it leaves it doubtful 



(1) whether the Tibeto-Chinese pro 



may be a projoctio 



merid 



of distribution or be due to a bif 



of t 

 of t 



Japi 



Sib 



iTian 



meridian within that pro 



and 



(2) whether the Himalaya- Yunnan province may be a projection of tho Tibeto- 

 Chinese meridian (whatever its derivation) or be a projection of the 



meridian of distribution through the Caucasus. 



But as these points of dubiety 



raise questions of possible alternative inter 



pretation and do not assail the truth of the general position 



we 



at liberty to proceed 



at once to a consideration of the special evidence from structure and, in ind 

 far it is corroborative of the general arithmetical evidence, to note at what 

 in what direction these doubtful problems are solved. 



r> 



1 



how 



and 



will 



been 



:ribution along Greenland, and that this meridian, at all events during the last southward migration, 



may have terminated in the cul-de-sac which its present physiography would suggest. The morphological evidence of 



Pediculari 



Hooker 



affinities, while Baffin Bay and Davis Strait indicate a sharper cleavage line than the ocean between East Greenland and 

 Norway/ It is interesting to observe that, so far as the evidence from Pedicularis is concerned, there is, in spite of the present 



.... * * .. * i * j;i.;~«« oa all*™ a olaavaxrn between America as a whole and Alaska, for of the tvralvA 



Arctic 



two — P 



pass to America, while the significance of this distribution i 

 Alaskan species, oniy two — jr. vwpwrwm***** — * • - • jr r & 



extremely slight since both these species are examples, as their zonal distribution testifies, of the Temperate- Intermedial 

 and not of the Arctic-Alpine Circumpolar Flora. This cleavage is confirmed by the evidence of P. sudetica, which on the 



has on the 



-European ana on me oiueuau ^^^.. — . 



American meridian been modified into a perfectly distinct, although still representative species, P. scopulorum. Besides the 

 negative evidence as regards the American meridian, there is positive evidence as regards the adjacent Japtn-Chma- 

 Himalaya meridian. One species (P. Ckamissonis) is confined to this mend.an, extending along it to Japan. Two others 



appear in Northern China. At the same time one of the endemic species, P. pedicdlata, 



~ " * "ike P. verticillata) distinctly separated 



a character which does not occur among 



P 



Oederi 



an species, and the other, P. Menziesti 



opposite 



iroHi an me species vji. tuc .i».*m^*w~— ~ . . - , t m • * • 



American species proper, but is, on the other hand, highly character^ of the Japan-Clnn. a.end.aa 



The cleavage betlen Alaska and Greenland pointed out by S.r J. D. Hooker ,s stnkmgly renfied by the evidence from 

 this genus While ten Alaskan species, or 83i per cent., occur in Arctic Am, only three (P. euparW* P. A,™ a, and 

 uns genus, wane tea ±- T| fd ence f p. euphrasmdes has to be discounted, and though there is 



P. lanata), or 25 per cent., occur in Greenland The "^eo^ ^J - ^ ^ ^ ^ fc ^ ^ ^ „ 



no evidence that the extension is not directum botn tue otn . ^ h 



For while 



P 



;hat the extension is not direct^ ooca uw Greenland> P . A ; r , M , a extends from Alaska through the whole of 

 confined to Eastern Arctic Asia, Alaska, an ^ • extension into Greenland is to be 



sought for. 



But while the cleavage between Greenland ana a contrary to indicate that the American province and Greenland 



between Greenland and the rest of America. It appears on ^ Greenland, three (P. Airjwta, P. tapponica. 



are on tbe same meridian of distribution 



^For whUeof the sis species that occur in Greenland, three (P. hinuta, P. tapponica. 



>n tne same meridian ox «.*.«—- A»>«rfa, P. lanata, and .P. eupAranotaes), or 50 pe 



P. Jfoi»««»>. or 50 per cent., extendto Lapland a (P . /cmwe « and P. / W o».c«) no fur< 



four, or 66% per cent., pass across Davis Strait two or . . .. 



no further thati 



American 



Ann. 



Eoy. Bot. Gaud- Calcutta, Vol. III. 



