NOTES. 
The ORIGIN OF MONOCOTYLEDONS.— In the genus Peperomia , , a perfectly 
typical and normally dicotyledonous genus, a small group of geophilous individuals 
has been observed which are peculiar in showing a pseudo-monocotyledonous mode 
of germination. In this group the embryo is, as I 
think, without doubt dicotyledonous, but, owing to 
the assumption of different functions by the two 
cotyledons, a striking analogy to a monocotyledonous 
type of embryo has been produced. 
In these Peperomias, as a reference to the pub- 
lished figures 1 will show, one of the cotyledons 
remains within the seed and is entirely a suctorial 
organ, though it retains, to a certain extent, its 
dorsiventral structure and possesses rudimentary 
or rather degenerate stomata. The other cotyledon, 
however, leaves the seed, a permanent space being 
left in the seed by its withdrawal, and becomes an 
assimilating organ and thus assumes the appearance 
of the characteristic ‘ first-leaf * of Monocotyledons. 
From a careful study of the germination of 
these geophilous forms, it has been suggested that 
the possible cotyledonary nature of the ‘ first-leaf ’ 
of Monocotyledons is worthy of some consideration. 
In the Bull. Soc. Bot. Fr., ser. iv, vol. viii, 1908, 
p. 165, MM. Buchet and Gatin describe and figure 
an interesting case of abnormal germination in 
Arisarum vulgar e, Targ.-Tozz. The cotyledon, 
normally a suctorial organ embedded in the endo- 
sperm, appears to have aborted, or perhaps to have 
been torn off, at an early stage in its development, 
since traces of torn tissue, which may be interpreted 
as the remains of the cotyledon sheath, were found 
at the place where this organ should have occurred. 
In the absence of the cotyledon the £ first-leaf ’ 
had performed the functions of an absorbent organ, 
for the lamina was found enfolded in the seed and 
was somewhat thicker than that of the normal 
‘ first-leaf’, in consequence, apparently, of its altered 
functions. The petiole had developed in the usual way, and the seed, with the 
1 Hill, A. W., in Ann. Bot., vol. xx, 1906, PI. XXIX and XXX and vol. xxi, PI. XV. 
[Annals of Botany, Vol. XXII. No. LXXXVIIL October, 1908.] 
3 c 
Fig. 1. Normal seedling of 
Arisarum vulgare Targ.-Tozz. 
Fig. 2. Abnormal seedling (nat. 
size) : s. seed ; p. petiole of the 
‘first leaf’; cp. petiole of the ab- 
sorbent cotyledon ; cs. cotyledonary 
sheath, represented by a small torn 
fragment in the abnormal seedling; 
r. radicle. (Copied from Bull. Soc. 
Bot. Fr., ser. iv, vol. viii, p. 166.) 
