REJUVENESCENCE IN NATURE. 59 



smaller euphyllary leaves, as for example in numerous 

 New Holland Myrtacece, as also in the South European 

 myrtle. While our firs and pines annually retrograde 

 to catapliyllary budding, we find the limits of the yearling 

 shoots of the more southern Conifers of the genera Arau- 

 caria and Cunninghamia, marked merely by smaller 

 euphyllary leaves. Many evergreen plants, however, of 

 our own climate, exhibit an exactly similar behaviour, as 

 for instance, Juniperis cotnmunis and Lycopodiimi anno- 

 tinum, in which the yearly lengths are only to be detected 

 by contracted places on the closely-leaved shoots. Among 

 herbaceous plants, Lysimachia Numnmlaria* and Isnardia 

 palustris belong here, these prolonging their creeping 

 stem by a considerable piece every new year, while the 

 lengths of the previous years die away. Veronica Cha- 

 madrys has the peculiarity herewith, that the euphyllary 

 shoot, from which the inflorescences go out laterally as 

 second axial systems, is erect until the time of flowering, 

 and only bends down its elongating end to the earth 

 after the plant has flowered, striking root then to ascend 

 again in the following year and bear flowering branches. f 

 In Glechoma hederacea, also, the shoots which are erect 

 until the time of flowering, turn back, at least in part, 

 towards the ground, not however to ascend again in the 

 next spring, but to send only branches upward, j 



The simplest mode in which the periodical Rejuve- 

 nescence presents itself to us, is that in which the same 

 sprout annually produces only one new leaf. Thus in 

 the brake fern [Pteris aquilind), which annually sends 

 forth from its subterraneous creeping rhizome only one 

 of its distichously-arranged leaves, not unfolded until the 

 third year, an euphyllary leaf, often of enormous size, 

 and pinnatifid in beautiful gradation up to the fourth 

 degree. So again in the Ophioylossum, already men- 

 tioned \ above, and at all events in our greenhouses the 



* Vide A. de St. Hilaire, 'Lepons de Botanique,' p. 103. 



t Ibid., p. 105. 



% Ibid,, p. 105. § See ante, p. 18. 



