188 Excerpta Botanica. 



or for a long time after ; in the minute flower, the tissue of 

 the calyx, and that of the ovary in the centre agglutinated 

 to it, being only visible, and a little later, in the interior of 

 this ovary, at first plain, two small lacunae are seen, which 

 finally enlarge, unite, and form one cell with contiguous walls. 



It is not until more than three months later that there is 

 perceived at the bottom of this compressed cavity a very 

 small, cone-shaped, pulpy body, accompanied by one or two 

 still smaller club-shaped filaments. These are so many erect 

 ovula, in two of which there is generally the commencement 

 of abortion. They are composed of utricules superposed in 

 circles, which in the ovulum to be developed are few in num- 

 ber, and in the abortive ovula are even reduced to a single 

 one. In these utricules are a nucleus, and very numerous 

 and minute grains of fecula. 



The ovulum, on its appearance, increases rapidly, and after 

 some days a small spot is detected towards its summit, which 

 indicates the embryo. The development of this embryo, 

 from its first appearance to maturity, has been observed by 

 M. Decaisne, and is similar to that of other Dicotyledons. 



It is different, however, with the body surrounding the 

 ovulum. In general, as is well known, the ovulum is formed of 

 many envelopes, enclosed one within the other, one or two 

 of those most exterior being open at their summits, and the 

 two innermost perfectly closed. 



But M. Decaisne has been unable to discover in the ovulum 

 of the Misseltoe any corresponding opening at the summit, 

 and he has been led to conclude that the exterior envelopes 

 (primine and secundine) are absent, and that the ovulum is 

 a naked nucleus. He has moreover ascertained this nut to 

 be composed of a homogeneous tissue throughout its whole 

 thickness, which immediately embraces the embryo, and 

 hence deduces the non-existence of a quintine or embryo- 

 nic sac. It is in reality an ovulum reduced to its simplest 

 expression, a sac enclosing the embryo. This sac thickens 

 and solidifies as it grows, and forms a perisperm, the colour 

 of which, being green, is unique among the families of plants. 

 M. Decaisne has followed the progress of this colouring, 

 which extends progressively from the base to the summit ; 

 he has seen, in the cellules of the nut, besides the nucleus 

 and the grains of fecula by w hich at first it was exclusively 

 filled, numerous green granules, which mingle with, but do 

 not cover, the others ; and he has thus observed this to be 

 the process of the green tint in the vegetable tissues. 



Another anomaly in the seed of Misseltoe is the plurality 

 of embryos. This plurality is not rare in a great many 



