Cockayne. — Development of Seedlings. 295 



liane, as described by Schenk* and Warming, and I think we 

 may safely conclude with Diels* that a number of our xero- 

 philous shrubs have thus descended from forest plants, and 

 in certain cases from lianes. 



The prickles are developed to a much greater extent in 

 the xerophilous than in the hygrophilous form of our plant, 

 although they are clearly an adaptation for climbing, as was 

 first shown by Kerner.f Afterwards, in the xerophyte, they 

 become of still greater use by binding into a wind-resisting 

 whole the numerous branches. The fallaciousness of Wallace's]: 

 idea that such prickles were a protection against snails has 

 been ably exposed by Mr. G. M. Thomson. § In the seedling 

 the prickles did not appear until quite late (the 8th leaf) in 

 its development ; but in the xerophilous form they increase 

 to a great extent, the conditions of its existence being seem- 

 ingly better suited for their appearance than are those more 

 sunless and damper ones to which the liane is exposed. 



No. 768. Ligusticum filifolium, Hook. f. Plate XII., 

 figs. 38, 41. 



The seed was collected on Jack's Pass, Hanmer Plains 

 district, at beginning of February, 1899. It was sown on the 

 6th September, 1899, and germinated on the 1st August, 

 1900. The young plants continued to make their appearance 

 until the middle of September. 1900. 



Description of Seedling. 



Early development : The cotyledons remain within the 

 seed-coat, and still surrounded by the walls of the mericarp, 

 absorbing nutriment until they are pulled out of the ground 

 and out of the pericarp by the lengthening of the hypocotyl, 

 and of their own peduncles more especially. Within the seed- 

 coat their upper flat surfaces are pressed together, absorbing 

 nutriment especially with their apices. Emerging from the 

 soil in a low arch, the short hypocotyl has become stout, and 

 offers good support for the petioles to pull their leaf-blades 

 out of their coverings. The cotyledons are at first very 

 narrow, with their laminae green, flat, and a little broader than 

 the longer filiform petioles, which are of reddish colour, faintly 

 channelled above and swollen at the base. At this stage the 

 cotyledons are sometimes bent or twisted. By the time the 

 cotyledons have reached a size of (laminae) 19 mm. x 2 mm., 

 and petioles 16 mm. in length, these latter have spread out 



* I.e., p. 247. 



t " Pflanzenleben," Leipzig, 1887, p. 637. Here a figure of the reduced 

 leaves is giverj, the plant being designated Rubus squarrosus. 

 I " Daiwinism," London and New York, 1889, 2 ,d ed., p. 433. 

 § " Nature," vol. 42, 1890, p. 222. 



