Page:Journal of botany, British and foreign, Volume 9 (1871).djvu/361

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.


SHORT NOTES AND QUERIES. 333

species amongst the Lake hills proper by sciidiiiii a specimen gathered by himself this autumn amongst the Helvellyn precipices at an elevatiou above sea-level of nearly 3000 feet. He has also met with Fyrola secitnda above Thirlraere, presumably in the same places where it was found many years ago by Messrs. Watson and Woods. — J. (x. Baker.

��"Right-handed v. Left-handed. — The question mooted by Mr. R. Tucker (Jouru. Bot. IX. p. 216), whether a given twining plant should be called chxtrorsum or sinistrorsum volubiUs, is, when properly looked at, one of such extreme simplicity that it certainly ought not to have greatly exercised either mathematicians or botanists. De Candolle, whom Prof. Clerk Maxwell is stated to have accused of leading astray and perverting many uidiappy naturalists in 1827, thus explains the matter in that year : — "On determine la direction des tiges volubiles en supposant qu'on est soi-mciue place au centre de la spii'ale, et que la tige tourne autour de son propre corps " (Organ. Veg. i. 156); and five years later he gave a similar explanation in his ' Fhysiologie Vegetale" (ii. 840). But the best discussion of the point with which I am acquainted is by Schleiden, who states the case clearly and cogently in these words : — " I will here very briefly discuss the terms right and left-wound stem, in regard to which much confusion prevails. The natural conception is this : the plant is developed from below upward, consequently it ascends; if, now, we use the expressions left and right concerning the plant, this can only have a meaning when we place ourselves in its position ; but we turn to the left in ascending if we have the axis of revolution to the left, to the right if we have it to the right. If we refer it to the course of the sun, we can evidently, in regard to our northern hemisphere, only bring the southern half of each revolution turned toward the sun into relation with its course, and then the right-wound spiral would go with the sun, the left-wound against it. Liniucus strangely used these terms in the opposite way, evidently starting from an obscure conception ; and many others have followed him therein. Many have quite reversed the thing, called left right and right left, till the whole matter had become confused. The reference to the course of the sun is, moreover, a very imperfect mark. It appears to me, however, that left and right-Avound cannot well be understood in any other way than that which 1 liave given " (Princ. of Sc. Bot. 233). A screw is called " right-haiuled " in mechanics vvhen a line touching the thread rises to the right (Golding Bird and l?rooke, Elem. Nat. Phil. ed. 5, p. 102) ; but it is obvious that the movement of rotation of such a screw is to the left. If a hollow screw of this kind — say a common corkscrew — be blackened inside and then rotated round a white stick, the marks it leaves will rise from the left to the right of the experimenter, though the motion of the screw itself is to the left. In the same way, a person ascending a spiral staircase, the axis of which is on his left-hand, is always turning to the left, but he woidd pass from the left to the right of an observer stationed at the circumference of the stair- case. Again, if the horses in a circus are riding round with their off legs toward the centre, they are going to the rigiit ; but, whilst traversing the semicircle nearest a spectator seated outside, they are passing to his left. The error of those who advocate and follow the Linnsean termino- logy is that, instead of describing the actual direction taken by the stem, they give the apparent one as seen by au observer standing without the

�� �