of the Embryos in the Seeds of Coniferse. 369 



Coniferce ; and it is worthy of remark, that while the female organ 

 in these two families exists in a simpler form than in other phae- 

 nogamous plants, the normal state of the impregnated ovulum is 

 much more complex, and might even be considered as compound, 

 or made up of the essential parts of several confluent ovula. 



On considering the well-known oeconomy of several Coniferce, 

 and especially of the genus Pinus, as at present limited, namely 

 in their requiring (at least) two seasons to ripen their cones, it 

 occurred to me that these plants, from the extreme slowness in 

 the process of maturation, conjoined with the considerable size of 

 their seeds, and also from the striking pecuharity already noticed, 

 were probably the best adapted for an investigation into the ori- 

 gin and successive changes of the vegetable embryo. 



With this view chiefly I commenced in the present summer 

 (1834) a series of observations, intending to follow them up from 

 the period when the enlargement of the impregnated cone begins 

 to take place, to its complete maturity at the end of the second 

 or beginning of the third year. 



h Pinus sylvestris was selected for this purpose, corresponding 

 observations being also made on other species, particularly Pi- 

 naster and Strobus ; and although the investigation is necessarily 

 incomplete, the facts already ascertained appear to me of sufficient 

 importance to be submitted to physiological botanists. 



In an essay on the organs and mode of fecundation in Or- 

 chidecB and Asclepiadea, published in 1831, I have given some 

 account of the earliest changes observable in the impregnated ovu- 

 lum of the former family ; and in noticing the jointed thread or 

 single series of cells by which the embryo is suspended, I re- 

 marked that the terminating cell or joint of this thread is pro- 

 bably the original state of what afterwards, from enlargement, 

 subdivision of its cavity, and deposition of granular matter in its 

 cells, becomes the more manifest rudiment of the future embryo. 



I had not indeed actually seen this joint in its supposed earliest 

 state ; the following observations on Pinus, however, will perhaps 

 be considered as giving additional probability to the conjecture. 



But before entering on my account of the origin and develop- 

 ment of the embryo in Pinus, I shall state briefly the still earlier 

 changes consequent to impregnation that take place in this genus ; 

 not only with a view of rendering the account of the embryo itself 

 more readily intelligible, but also in confirmation of the opinion 

 formerly advanced on the nature of the female organ in Coniferce 

 and Cycadece. 



The first and most evident change observable is the production 

 or separation of a distinct body within the nucleus of the ovulum, 

 which, before impregnation, is a solid uniform substance. 



Ann, ^ Mag. N. Hist. Vol xiii. 2 B 



