554 Thiselton-Dyer . — Morphological Notes. 
the work of rupturing the seed and placing the plumular bud 
and root by a rapid elongation which commonly brings the 
plumular bud above ground, protected it may be by the 
cotyledons. These latter may then become the first assimi- 
lating organs unlike or like to the epicotylar leaves V 
This, though a guarded statement, appears to imply that 
the cotyledons are more or less organs sui generis , and not 
homologous with ordinary or epicotylar leaves. It brought 
to my recollection some observations which I made some 
years ago, and which it now seems worth while to put on 
record. It is well known that the Sycomore [Acer Pseudo - 
platanus') reproduces itself spontaneously from seed with great 
readiness. This was the case with a tree at Kew which was 
ultimately, for unavoidable reasons, cut down. A notable 
proportion of the seedlings of this tree came up with three 
cotyledons. The circumstance is not, however, unusual, and 
similar cases are discussed in Duchartre’s classical Memoire 
sur les Embryons qui ont ete decrits cotnme Polycotyles in the 
‘ Annales des Sciences naturelles’ (3® ser., x, pp. 210-11). 
I quote his account : — 
{ Embryons a cotyledons accidentellement partcigls . 
‘ Sur plusieurs points des environs de Paris, notamment 
a Meudon et Bellevue, on remarque au printemps, le long 
des allees, dans le voisinage des jardins et des pares, une 
quantite considerable de germinations des Erables Plane 
\Acer platanoides\ et Sycomore. Leurs grandes feuilles semi- 
nales, lanceolees-oblongues, entires, y forment quelquefois 
une sorte de gazon : or, parmi ces nombreuses germinations 
il est facile de trouver tous les degres de division mediane 
des feuilles seminales, depuis une simple echancrure j.usqu’a 
une partition tellement profonde, qu’elle ferait croire, dans 
certains cas, a l’existence de trois cotyledons distincts et 
separes. Je me borne a figurer ici deux de ces germinations, 
choisies entre beaucoup dautres ; dont Pune presente un 
1 Nature, lxiv, pp. 560, 561. 
