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 sionificance, 
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 
Passiflora and Viburnum Opulus, 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- 
eynous disc.’ Moquin has seen similar instances in 
the flowers of a Rose, Hypericum, 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 Trécul.’ 
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 import; sometimes they are degenerated 
peduncles, as in passion-flowers, or vines; at other 
times they are of foliar origin; or, again, they may 
proceed from the segments of the perianth, as in 
1 “Consid. Org. Fleur.,’ p. 44, pl. ii, fig. 23. 
2 «Ann. Sc. Nat.,’ 3 ser., Bot. ix, pl. 6, ff. 1, 2. 
3 * Ann. Se. Nat.,’ 3_ser., Bot. 1855, pp. 297, et 303. 
4 «Trans. Linn. Soc.,’ xxii, p. 415. 
