72 



same leaf in a natural way, an actual impregnation takes place, 

 although there does not exist that difference which the other 

 higher plants exhibit between stem and leaves. At the same 

 time these observations confirm M. MohPs view, that the 

 spores of Cryptogamia and all lower plants in general, are 

 produced, like the pollen granules of the higher plants, from 

 modified leaves. 



M. Link* has published the second part of his Elements 

 of Botany, which contains (p. 44 331) the important chap- 

 ter on the inflorescence and fruit of plants. This second 

 part is also as rich in observations as the first, and above 

 all I must direct attention to the morphological views of the 

 author expressed in this work ; they are the result of many 

 years' study of nature. 



The observations of M. Fritzsche t on the structure of pol- 

 len, which we mentioned in our last year's report J, have now 

 been published entire. The work is divided into two sections : 

 the first treats of the structure of pollen in general, the second 

 on the tunics of the pollen. The whole is written without 

 any mention of the literature on the subject, as the perspi- 

 cuity of this difficult subject would in M. Fritzsche's opinion 

 have been thereby endangered. 



The exposition of the first memoir on pollen in general be- 

 gins with the examination of the anthers of Chara, which it 

 is well known deviate very much from the general rule. The 

 coats of the anthers of the Chares are in general composed of 

 eight flat-pressed triangular cells, each four of which form a 

 hemisphere; the superior hemisphere is closed, the inferior 

 one on the contrary has at the spot where it is attached a round 

 aperture, which is formed by semicircular excisions of the tri- 

 angle that take part in its formation. The structure of these 

 triangular cells is very fully described ; they contain a clear un- 

 coloured mucus (this mucus is stated to be coloured probably 

 from a misprint) and the inner surface of the parietes situated 

 towards the centre of the anthers is covered with a layer of red 

 granules, which again exhibit in their substance a quantity of 



* Elementa philosophise botanicse, torn. ii. Edit, altera, Berolini, 1837. 

 f Ueber den Pollen. Mit 13 colorirten Steindriicken. St. Petersburg, 1837. 

 4to. Printed separately from the Memoirs of the Royal Academy. 

 J Lond. and Edinb. Philosophical Magazine, vol. xi. p. 165. 



