64 
REPORT ON BOTANY, MDCCCXLI : 
on this subject, in the third volume of the author’s physiology. 
He then speaks of polyembryony, and gives a description of 
the development of the ovule in the mistletoe. There is no 
particular pistil, he states, in the mistletoe, and, therefore, 
likewise no real ovarium ; the ovule is a mere naked nucleus, 
the point of which is free and projecting, and at the same 
time serves as a stigma, as it is the immediate recipient of 
the pollen. A cavity is produced in this nucleus, and within it 
the embryo sacs, of which there are often two or more, exhibit 
themselves in the middle of April. It is then that the embryo 
developes itself. The author did not observe any pollen tubes. 
It is evident, that what the author terms embryo sacs, 
Decaisne describes as ovules. The examination of these ovules 
has been instituted with much greater care by Decaisne, and 
if Meyen had continued his researches long enough, he no 
doubt would have been convinced of his error. He likewise 
did not think of the pericarpium, nor of the berry. Meyen 
always aimed too much at novelty, at producing a striking 
effect, and endeavoured, in this way, to outdo his antagonists. 
This statement should be compared with the author’s expla- 
nation of the peculiar position of the embryos in the mistletoe 
seed, when several of them occur in one and the same seed, 
in Wiegmann’s Archiv for 1840, vol. i. p. 164, in which he 
has well observed the union of the embryos with their cotyle- 
donary ends. 
Goeppert enumerates an instance of polyembryony in Thuja 
orientalis, in the Eeport of the Labours of the Silesian 
Society for Native Culture, 1840, p. 99. 
M. Arndt, of Osnabriick, has instituted observations (Flora, 
1840, p. 477) on the Impregnation of the Flowers of Lopezia 
mexieana. The anther burst on the inside towards the 
stigma ; the place where the anther- valve is about to open is 
indicated by a glittering longitudinal stripe. The bursting of 
the valve takes place when the petals of the corolla are still 
entirely closed, which is, however, perfectly developed in all 
its parts. After the bursting, the filaments increase in size, 
turn round and round, and finally throw off the emptied pollen 
tubes. 
456 
