328 ANNUAL OF SCIENTIFIC DISCOVERY. 



CLniBING PLANTS. BY CHARLES DARWIN. 



"Plants become climbers in order to reach the lioflit, and ex- 

 pose a larire surlHco of leaves to its action and th;it of the Irec! air. 

 Their advantai^e is, tiiat they do it with Avoiidcrt'idly little; expemli- 

 ture of or<2:anized matter in comparison with trees, which have to 

 support a heavy load of branches by a massive trunk. Of the 

 different sorts of climliers, hook-elimliers are the least efficient, at 

 least in temperate climates, as they climb only in the midst of an 

 entanirlcd mass of vegetation. Next are rout-elimbers, which 

 are admirably' adapted to ascend naked faces of rock ; but when 

 they climb trees, they must keep much in the shade, and follow 

 the tnnd<, for their rootlets can adhere only !)}• long-continued 

 and close eontai-t with a steady surface. Third, spiral-twiners, 

 with leaf-climbers and tendril-bearers, which agree in their power 

 of spontaneously revolving and of grasping objects which they 

 reach, are the most nmnerousin kinds, and most jx-rfeet in mech- 

 anism ; they can easily pass tVom Ijranch to branch, and securely 

 ramlde over a wide and sun-lit surface." ..." Why have 

 nearly all the plants in so many aboriginally twining groups been 

 converted into leaf-climbers or tendril-liearers? Of what advan- 

 tage could this have been to them? Why did they not remain 

 simple twiners? AVe can see several reasons. It might bean 

 ad\ antage to a plant .to aequii'e a thicker stem, with short inter- 

 nodes, bearing many or large; leaves; "and such stems are ill-fitted 

 for twining. Any one who will look, during windy weather at 

 twining plants, will see that they are easily blown from their sup- 

 port; not so with tendnl-bearers or leaf-climbers, for they quickly 

 and lirmly grasj:) their sujjport by a much more efficient kind of 

 movement. . . . From possessing the powder of movement 

 or contact, a tendril can be made very long arid thin ; so tiiat 

 little organic matter is expended in their develoinnent, and yet a 

 wide circle is swept." — Journal of Linncean Society, 18G6. 



VEGETABLE PARASITES OF MAN. 



At a recent meeting of the Quekett Microscopical Society, a 

 paper w.is read i^j'^ Dr. Tilbury Fox, on the " Vegetable Para- 

 sitism of Living Beings," of no little interest, as bearing upon the 

 "blue mist" question raised by Mr. Glaisher. It has been sug- 

 gested that the blue mist may be due to the presence in the 

 atmosphere of the spores of low forms of vegetable life. Dr. 

 Fox's paper embraced an account of the life and influence of 

 minute fungi in general ; showed that the presence of cell-struc- 

 tures was to be expected in all situations to which the air has 

 access, their discovery hitherto having been delayed liy the 

 absence of observation and the want of a sufficiently high-pow- 

 ered microscope. They are especially prevalent at such seasons 

 as the i^resent, in which rusts and mildews have abounded. 

 These germs are very light, and can be easily waited by the air 

 from place to place. They seem not only to be found in spots acces- 



