February 1, 1896.] 



KNOWLEDGE, 



25 



ILLUSTRATED MAGAZINE 



JTERATI 



LONDON: FEBRUARY 1, 1896. 



CONTENTS. 



^ PAGE 



Some Curious Facts in Plant Distribution. By W. 



BoTi'ixG Hemsley, F.E.S " ... 25 



Waves. — II. The Waves of the Sea Shore. Bv Vaughan 



COEXISH, M.Sc. [Illustrated) {Plate) ... ' 26 



Antarctic Exploration. By Wihiam S. Beuce 28 



Notices of Books. {Illustrated) 31 



Letters: — W. H. Monce ; Geographer .. ... ... 34 



Greek Vases. — I. Introductory. Bv H. B. Walters, 



M.A., F.S.A. {Illustrated) ' 36 



What is a Nebula? Bv E. Walter Mausdeh, F.R.A.S. 



(Plate) ^ 38 



Nebula near 15 Monocerotis. By Isaac Roberts, D.Se., 



F.K.S 39 



Comets of Short Period. 

 F.E.A.S 



By W. E. Plf-Mmee, M.A., 



40 



The Spanish Chestnut. By Geoeoe Paxton. {Illustrated) 43 

 Life in Babylonia in Patriarchal Times. By Tueo. G. 



Pinches. M.R.A.S. [Illustrated) ... ... ' 44 



Science Notes 46 



The Face of the Sky for February. By Herbert 



Sadlee, F.R.A.S 47 



Chess Column. By C. D. Lococe, B_A..Oion 47 



SOME CURIOUS FACTS IN PLANT 

 DISTRIBUTION. 



By W. BoTTiN'G Hemsley, F.E.S. 



THE present distribution of plants, apart from those 

 low in the scale of organisms, exhibits some very 

 curious phenomena. Perhaps those most obvious 

 to the majority of persons are consequent upon the 

 spread of European peoples over other parts of the 

 globe. The domestic weeds of ancient civilization, the 

 road-side weeds and the cornfield weeds, have accompanied 

 man in his most distant wanderings, and in many instances 

 have developed increased vigour and a power of coloniza- 

 tion unsurpassed by man himself. In some instances the 

 reproduction and spread of these weeds is so rapid as to 

 become a great scourge to agriculture, overrunning and 

 destroying crops almost as eft'ectually as swarms of locusts ; 

 and laws have been framed making it compulsory on 

 farmers to keep their land free of these prolific strangers. 

 Sometimes it is a new weed that makes its appearance and 

 propagates itself in this extraordinary manner, advancing 

 from field to field, farm to farm, county to county, and 

 State to State, at an incredible pace. During the last three 

 or four years the so-called Itussian thistle (Salanlu Kali, 

 var. Traiius] has been occupying the serious attention 

 of the farmers and legislators of the Eastern and Central 

 States of North America, and it is already the subject of a 

 considerable literature. Thousands of square miles are 



infested, and the loss resulting therefrom in 1892 was 

 estimated to exceed two million dollars ! 



But the object of this article is to direct attention to 

 some of the phenomena of the distribution and existence 

 of plants in nature, uninfluenced and unaffected by man, 

 either du-ectly or indirectly — that is to say, to the latitu- 

 dinal limits, the altitudinal limits, and other interesting 

 facts of the present distribution of flowering plants. 



In the highest latitudes yet reached in the west, in 

 Ellesmere Land and Grinnell Land, between 80^ and 

 83° 6' north latitude, the ground in locaUties the most 

 favourable to the development of vegetation is carpeted 

 with plants, many of them having brilliantly coloured 

 flowers, produced in great profusion during the short but 

 continuous summer that there obtains. About seventy 

 species were collected within the latitudes named by the 

 naturalists of the last British Polar Expedition, and they 

 included such familiar showy plants as Papaicr alpimim, 

 Silene iiciiuUs, Dri/iis nrtopi'falci, Sa.rifraiia oppositifolia, and 

 Epilohium latifoUum. 



The Austrians found a very different condition of things 

 in the same latitudes in Franz Josef Land, eastward of 

 Spitzbergen. Plants were found, and of the same species, 

 but in an extremely stunted state, with scarcely a flower 

 to be seen, and nowhere was there continuous vegetation 

 a few square feet in extent. 



In these very high latitudes seed is rarely, if ever, 

 perfected, and plants increase only by vegetative develop- 

 ment — suckers, underground stems, and traiUng rooting 

 stems. Yet the greatest cold experienced — upwards of one 

 hundred degrees (Fahrenheit) of frost— did not impair the 

 vitality of wheat that had been fully exposed for four winters 

 and four summers. It should be mentioned that none of 

 the plants inhabiting these high latitudes are peculiar to 

 the region ; that very few species are confined to the Arctic 

 regions ; and that many of them are widely spread in 

 Alpine regions of lower latitudes, some even recurring on 

 the mountains within the tropics, and a few reach the 

 southern limits of vegetation. 



In the southern hemisphere there are now no flowering 

 (jilumeroijamk) plants growing within thirty-five degrees 

 of the Pole, " and countries in us high a latitude as Scotland 

 are absolutely ice-bound. South Georgia, in the American 

 region, and Macquarie Island, in the New Zealand region, 

 may serve to illustrate the Antarctic flora and the southern 

 limits of flowering plants. They are small islands of 

 comparatively slight elevation, and both situated m 5-1° 

 south latitude. South Georgia is about a thousand miles 

 east of Cape Horn, and nearly as far from the Falkland 

 Islands, the nearest land, except some very small islands 

 concerning the vegetation of which nothing is known. 



Its exceedingly meagre flora has probably been exhaus- 

 tively investigated, and the result is a list of thirteen species 

 of flowering plants and no ferns. Not one of these species 

 is peculiar to the island, and nine out of the thirteen 

 inhabit both the American and the Australasian or New 

 Zealand regions. When we remember that the Antarctic 

 flora now exists only in such isolated and distant fragments, 

 we are hardly prepared to find almost the same homo- 

 geneity as in the north, where there is practically a 

 continuity of land. Yet so it is ; and the only satisfactory 

 solution of the problem is a former greater laud connection 

 and continuous flora, probably in higher latitudes than the 

 existing fragments. One of the tasks of Antarctic 

 explorers is to search for fossil remains, which might 



• Should there be no error in locality, there is a single known 

 exception. In the Kew Herbarium is a spei-inicn of a urass {Aira 

 anlarclinil liibelled : " Ni-w South Shetlanil. Dr. Hisihts." 



