HARD WICKE'S SCIENCE- G OSSIP. 



267 



be rubbed briskly to and fro across them, a shrill 

 sound is produced, increasing of course in pitch and 

 also in intensity with the greater rapidity of motion. 

 But I doubt whether a sufficient quickness of motion 

 could be given by the hand so as to produce the 

 pitch in sound of the cricket, that requiring at least 

 24,000 vibrations a second. We may fully compre- 

 hend that a shrill sound could be produced by means 

 of the metal or by the " Siren," but looking upon 

 the almost microscopic nature of the cricket " file," it 

 appears hard to believe that can be the principal 

 instrument concerned in the production of the loud 

 and shrill sound, yet it is generally conceded that 

 such is the case. Although I have satisfied myself 

 as to the instrument used by the "cri-cri," as the 

 French name the insect, yet my wonder and admira- 

 tion is but increased by the examination, and I shall 

 listen to the shrill note with undiminished interest. 



THE ORIGIN OF OUR VERNAL FLORA. 



THE following remarks on this interesting subject 

 have just appeared in "Nature," by Dr. J. E, 

 Taylor. It is usual to assign an Arctic origin to our 

 mountain flora, and floral comparisons and statistics 

 fully bear out this brilliant generalisation. It is 

 formulated that height above the sea-level is 

 climatally equivalent to northern latitude. This is 

 an assumption that flowering plants are largely 

 conditioned by heat. Thus latitude and oreographical 

 habitats are more or less equal. 



Might I introduce another element into this 

 question? Seeing that temperature is so largely 

 influential in explaining the distribution of flowering 

 plants, it occurs to me that not only may height 

 above the sea-level answer to northern distribution, 

 but seasonal occurrence as well. 



All botanists must have been struck by the fact 

 that the earliest plants to bloom among our vernal 

 flora are genera peculiarly Alpine. In some instances 

 (as with Chrysosplctiiiim oppositifoUum and C. alterni- 

 folium) the species are identical. These latter plants 

 blossom with us in March or April; within the 

 Arctic circle not until June and July, and even so 

 late as August. Thus, with them, seasonal blossom- 

 ing is equivalent to northern altitude, as regards the 

 thermal conditions under which they flower. The 

 generic names of all our early flowering plants are 

 those pre-eminently Alpine and Arctic in their 

 distribution— Potentilla, Stellaria, Saxifraga, Chry- 

 sosplenium, Draba, Ranunculus, Cardamine, Alsine, 

 &c. I contend, therefore, that our vernal flora is 

 explained by the fact that their seasonal occurrence, 

 as regards temperature, is equivalent both to height 

 above the sea-level and northern latitude. In every 

 instance it will be found that the blossoming of the 

 species of the above genera necessarily takes place, in 

 Great Britain, two or three months earlier than within 



the polar circle. May we not therefore contend that 

 we owe our English vernal flora to the same causes as 

 distributed our English Alpine plants ; and that they 

 are as much protected by being able to flower earlier 

 in the year, as if they had been located on the tops 

 of high hills and mountains ? 



The power to endure cold and wet displayed by 

 many members of our vernal flora is very remarkable. 

 Thus Ranunculus hulbosus and R. acris, Stellaria 

 media, &c., are frequently found in flower all through 

 the winter, unless the season be extra cold. Many 

 other early bloomers among our common flowers are 

 also remarkable for their durability, whilst the late 

 flowering plants are equally noticeable for the short 

 space during which they bloom. This indicates a 

 hardihood on the part of our vernal flora which 

 cannot be explained except by reference to the 

 climatal experience of the species. Some of them, as 

 the groundsel and chickweed, may have exchanged 

 an entomophilous for an anemophilous habit, or have 

 become self-fertilised by the change. 



Again, it must have been observed that many of 

 our early flowering plants display a tendency towards 

 a seasonal division of labour. All of them either 

 flower before they leaf, or show a tendency to do so, 

 as with the coltsfoot [Tiissilago farfara), the crocus 

 (C. z'ernus), the snow-drop (Gala7ithus tiivalis), &c. 

 Even the violets ( Viola odorata and V. canina), the 

 daffodil, primrose, cowslip, &c., although they in 

 part leaf when they flower, develop leaves much more 

 abundantly after flowering than before, thus showing 

 an inclination towards dividing the period of active life 

 into two distinct stages — the reproductive and vege- 

 tative. Every one knows how completely this has 

 been effected by the meadow saffron \Colchicum 

 aufiimnale). My impression is that this early flower- 

 ing tendency is a survival of the habit these plants 

 had to blossom under more rigorous climatal con- 

 ditions ; in short, that our vernal flora must hav<- 

 the same origin assigned to it as an Alpine ; that it 

 has survived through being able to bloom at an early 

 period of the year at low levels, instead of flowering 

 at a later season higher up, above the sea level ; 

 protection and advantage being secured in both 

 instances. 



Young Frogs. — I see that in Science-Gossip 

 for September ist, 1882, A. H. Fisher states that he 

 was unable to keep young frogs longer than three 

 weeks. I have kept frogs after the tadpole stage for 

 ten weeks in confinement, feeding them four or three 

 times a day with aphides or raw meat, placed on the 

 point of a knitting-pin. They grew but little ; and 

 after ten weeks I placed them in the garden at the 

 end of July 1 881. Seven are still in the garden, very 

 tame, and about an inch and a half long (exclusive of 

 legs). These frogs were hatched from spawn^in an 

 aquarium. — F. Jru/ell. 



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