HYPOCOTTLS. EPICOTYLS, ETC., Chap. 11. 



Stem of the parasitic and leafless Monotropa hijpopitijs. 

 With Eelleborus niger, the flower-stems, which rise up 

 independently of the leaves, likewise break through 

 the ground as arches. This is also the case with the 

 greatly elongated flower-stems, as well as with the 

 petioles of Epimedium pinnatuni. So it is with the 

 petioles of Ranunculus fiearia, when they have to break 

 through the ground, but when they arise from the 

 summit of the bulb above ground, they are from the 

 first quite straight ; and this is a fact which deserves 

 notice. The rachis of the bracken fern (Pteris aqui- 

 lina), and of some, probably many, other ferns, like- 

 wise rises above ground under the form of an arch. 

 No doubt other analogous instances could be found by 

 careful search. In all ordinary cases of bulbs, rhizomes, 



tanean soale-liku leaves ; not that 

 there is any leason to suppose 

 that the secretion is a speoiul 

 adaptation for Ihis purpose: it 

 probably follows from the great 

 quantity of sap abaorlied in the 

 early spring by the parasitic roots. 

 After a long period without any 

 rain, the earth hail become light- 

 coloured and very dry, but it was 

 dark-coloured and damp, even in 

 parts quite wit. for a distiince of 

 a1 least six inches all round cacli 

 flower-stem. The water is secreteil 

 by glands (ilesciibed by Cohn, 

 'ijericlit. Bot. Sect, der Selile- 

 Biachen Gesell.,' 1870, p. UH) 

 which line the lougitudiiial 

 channels running through e.ich 

 scale-like leaf. A large plant was 

 dug up, washed so as to remove 

 tlie earth, left tor some lime to 

 drain, and then placed in the 

 evening on a dry glass-plate, 

 covered with a bell-glnss, and by 

 next morning it liail secreted a 

 large pool of -wutpr. The pi te 

 was wiped dry, and in the oouise 

 of tlie sucoeuding 7 or 8 hours 



another little pool was secreted, 

 and after , 16 additional hours 

 several large drops. A smaller 

 plant was washed and placed in a 

 large jar, which was left inclined 

 for an hour, by which time nn 

 more water drained off. The jiir 

 was then placed upright and 

 closed : after 23 hours twodriichms 

 of water were collected from the 

 bottom, and a little more after 2.5 

 adilitional hours. The flower- 

 stems were now cut off, for they 

 do not secrete, and the subter- 

 ranean part of tlie plant was found 

 to weigh 106-8 grams (1611 

 grains), and the water secreted 

 during the 48 . hours weighed 

 11-9 giams (1>3 grains). — that is, 

 one-ninth of the whole weight of 

 the plant, excluding the flower- 

 stems. We should remember that 

 plants in a state of nature would 

 probably secrete in 48 hours much 

 more than the above large amount, 

 for their roots would continue all 

 the time absorbing sap from the 

 plant on which they were pars' 

 sitio. 



