270 



KNOWLEDGE. 



[December 1, 1896. 



of the finer examples of rod-figured vases can be later than 

 B.C. -100, while historical evidence taken in conjunction 

 with the results of excavations in Sicily and ithodes, and 

 at Naukratis, points to the fact that apparently late red- 

 figured vases found in those places cannot bo later than 

 the fifth century. 



Description ui- Plate. 



1. Kvlix (goblet), signed hy Kpiktetos. In interior, man playing 

 flutes and girl dancing. About 500 B.C. 



2. Kjlix, signed by Euphronios. In interior, elderly man and 

 girl conyersing. About 480 B.C. 



3. Kjlix, signed by ]!rygo9. In interior, woman giving drink to 

 departing warrior. About 400 n.c. 



4. Kotvlo (beaker), signed by Hieron. Subject symbolical of the 

 introduction of agriculture into Attica: Triptolemos sent forth by 

 Demeter from Eleueis. About 470 B.C. 



6. Krater (mixing bowl), of fine style. Subject: Sunrise, repre- 

 sented by the sun-god in his chariot and four boys diving (indicating 

 stars setting). About 440 B.C. 



6. Pyxis (toilet box), of late fine style. On the top, the death of 

 Pentbeus; round the side, the chariot of Aphrodite drawn by two 

 attendant genii. About 420 B.C. 



SOME CURIOUS FACTS IN PLANT 

 DISTRIBUTION.-VI. 



By W. BoTTiNG Hemsley, F.R.S. 



IN the first of this series of articles (February, 1896) 

 some particulars were given of the latitudinal 

 distribution of flowering plants. It was shown 

 that, with one possibly doubtful exception, no 

 flowering plants existed in the remote islands of the 

 southern hemisphere within thirty-five degrees of the Pole, 

 and probably nowhere within thirty-four degrees ; whereas 

 in the northern hemisphere about seventy species had been 

 collected between latitude 80- and 83", or within seven 

 degrees to ten degrees of the Pole. It was further pointed 

 out that the plants of the southern limits of vegetation 

 have very small green or dull-coloured flowers ; whereas, 

 in the north, showy flowers are not uncommon, coexisting 

 with bees and butterflies. Everybody knows that plants, 

 like animals, are afi'ected by temperature, and it has been 

 ascertained by observation and experiment that a certain 

 amount of temperature is necessary for the perfect develop- 

 ment of a plant, the amount varying for different plants. 

 Some trees and shrubs that thrive in this country rarely, 

 if ever, flower ; others flower, but never, or very seldom, 

 produce seed. This difference in constitution is a problem 

 difiicult of solution. The dahlia and heliotrope, the potato 

 and kidney-bean, all attain full development in this country 

 during the warmer months, but their constitution appears 

 to be the same as when they were first introduced, or the 

 same as newly-imported strains, for a very slight frost 

 destroys their tissues, and a healthy plant is thereby 

 reduced, in less than twenty -four hours, to a black decaying 

 mass. To look at, a seedling groundsel is as delicate and 

 tender an organism as a seedling cucumber ; yet the seed of 

 one will germinate and grow in a temperature a few degrees 

 above the freezing point, whilst the other requires a 

 considerable amount of heat, and only really flourishes in 

 the open air in England during our most favourable — that 

 is to say, our warmest — summers. On the other hand, 

 there are some plants of a hardy nature that will grow under 

 widely different atmospheric conditions. In other words, the 

 difference between the maximum and minimum sums of 

 temperature under which they will fully develop is very 

 large. Other plants will bear one or more sharp frosts 

 without much injury, but a long continuation or succession 

 of sharp frosts wiU kill them. Perpetual frost would, of 

 course, eventually destroy all plant life, because it prevents 



growth. But in Arctic and Alpine regions — in fact, in 

 nearly all cold countries— vegetation is protected by snow, 

 and it may be said in a general way that the temperature 

 of tho soil is higher in cold weather and lower in hot 

 weather than that of the air. Other plants are prevented 

 from dying out, through exposure to excessive heat, or 

 cold, or drought, by the fact that, although they flower 

 only once, they produce seed in abundance. The seeds of 

 such plants will bear exposure to the greatest solar heat, 

 or to intense frost, or to the most prolonged droughts, 

 without losing their vitality. These general explanations 

 will render intelligible the existence and reproduction of 

 plants under conditions that one might otherwise con- 

 sider destructive of living organisms, whether animal or 

 vegetable. 



Generally speaking, the same causes determine the 

 character and composition of vegetation in high altitudes 

 as well as in high latitudes. 



In the extreme land limit reached by the British Polar 

 Expedition in 1876 flowering plants were found, and there 

 is every reason to suppose that if there were land at the 

 Pole itself there also plants would exist. Ward Hunt 

 Island, 83° 4', and Cape Columbia, 88° 8', were the most 

 northern points at which plants were collected. In the 

 latter locality grew Saxifraga oppodti folia, a charming 

 little plant that inhabits the mountains of tho British 

 Islands, and also grows freely under cultivation down to 

 the sea-level in the South of England. It is found 

 throughout the Arctic zone, and has an exceedingly wide 

 range outside of the Arctic regions, in the mountains of 

 Europe and Asia, including the Himalayas, up to an 

 altitude of seventeen thousand feet. 



In this connection it is worthy of note that a saxifrage 

 {Saxifratja BoiissinijduUii) has been found at as great an 

 altitude — namely, sixteen thousand five hundred feet — if 

 not greater, than any other flowering plant in the Andes 

 of South America. When this discovery was made, it 

 was supposed that there was little probability of any 

 flowering plant being found at a greater elevation in any 

 part of the world, especially as the locality is close under 

 the Equator ; but, as will be presently shown, plants have 

 since been discovered at much greater elevations. 



It is singular, too, that another member of the same 

 genus (S. hicuspidata) reaches the southern Umit of 

 flowering plants in Hermite Island, Cape Horn. This 

 species is remarkable for its very small flowers, and the 

 forcep-like appendages at the tips of the leaves, very 

 similar to those of an earwig. 



Papaver nudicaule, commonly cultivated and known as 

 the Iceland poppy, was collected on Ward Hunt Island. 

 This also ranges all round the northern hemisphere, but 

 it is not wild in the British Islands. 



Altogether, thirty species of flowering plants were col- 

 lected north of the eighty-second parallel of latitude, and 

 about half of them are British. 



As to the conditions under which plants grow in these 

 high latitudes, and the forms they assume, it may be 

 stated generally that they gradually diminish in size and 

 frequency ; that they never produce ripe seed, and there- 

 fore only increase by their creeping stems, above or below 

 the surface of the soil. The vegetation on the northern 

 slopes is more luxuriant than on the southern, because it 

 gets more sun on that side. Observations on the vertical 

 range of plants in Discovery Bay (81° 12) gave two 

 thousand as the maximum. To this altitude the poppy, 

 two species of saxifrage, and a kind of whitlow grass 

 ascended. Indeed, vegetation is limited by the line of 

 perpetual snow, varying greatly in different localities. 



Scanty as the herbage is, a variety of animals subsist 



