DEGENERATION. 473 



They occur normally in the sepals of Paronychia 

 serpyllifolia and other plants. 



Formation of glands. Under this name are associated 

 a number of (generally) rudimentary organs very 

 different in their morphological nature and significance, 

 and also in their functions. Some are truly glandular 

 or secreting organs, while others have no visible office. 

 Anything like a complete account of these structures 

 would be out of place, and reference is only made to 

 them here on account of the occasional existence of 

 intermediate forms, which throw light on the morpho- 

 logical significance of these structures. Thus, in 

 Passijiora and Viburmim OpuluSy the so-called glands 

 on the sides of the petiole appear to represent leaflets, 

 and are not unfrequently developed as such. 



M. Dunal observed a flower of Cistus vaginatus in 

 which some of the stamens were replaced by an hypo- 

 gynous disc.^ Moquin has seen similar instances in 

 the flowers of a Rose, Hyjyericum, and Poppy. 



M. Planchon^ gives an account of some very curious 

 malformations in Drosera intermedia, which go to show 

 that the ovules are homologous with the glandular 

 hairs on the margins of the leaves of these plants, an 

 opinion corroborated by the researches of MM. Gron- 

 land and Trecul.^ 



Dr. Hooker shows that the pitcher of Nepenthes is 

 due to a modification of a gland placed at the extremity 

 of the midrib.* 



Formation of tendrils. These are of very varied mor- 

 phological iniport; sometimes they are degenerated 

 peduncles, as in passion-flowers, or vines; at other 

 times they are of fohar origin ; or, again, they may 

 proceed from the segments of the perianth, as in 



' ' Consid. Org. Fleur.,' p. 44, pi. ii, fig. 23. 

 - ' Ann. Sc. Nat.,' 3 ser., Bot. ix, pi. 6, S. I, 2. 

 = ' Ann. Sc. Nat.,' S.ser., Bot. 1855, pp. 297, et 303. 

 * ' Trans. Linn. Soc.,' xxii, p. 415. 



