174 Meyen^s Report for 1839 oh Physiological Botany. 



itself with its swollen end (in the form of a retort) over one 

 of the apices of the sac of the neighbouring embryo. M. De- 

 caisne considers this peculiar tube to be a nutritive vessel, 

 which replaces at the same time the chalaza ; and I myself 

 believe (although 1 have not examined the subject) that this 

 tube is either directly produced out of the end of the pollen- 

 tube, as in the case of Mesembryanthemum linguarforme, or 

 that it is a peculiar formation of the embryo-supporter, as in 

 Ceratophyllum, etc. 



M. Emil Kratzmann*, in his inaugural dissertation, has 

 treated of the seeds of plants ; and although he remarks in the 

 introduction, that his work is only a compilation and does not 

 pretend to originality, still I cannot but recommend this care- 

 fully compiled and complete paper to all those who have not 

 access to the larger botanical w^orks. The treatise is divided 

 into five parts ; namely, of the praeformation-stadium of the 

 seed, of its production and formation, its evolution (ripening), 

 then of the structure of the rip& seed, etc., and lastly of the 

 circumstances under which the germination of the seed takes 

 place. 



M. Adrien de Jussieuf has published a very interesting 

 research on the embryos of the Monocotyledons : after an hi- 

 storical introduction he gives the general characters of the mo- 

 nocotyledonous embryos, and then proceeds to the enumera- 

 tion of the peculiarities exhibited by the embryos of the differ- 

 ent genera. The most common form of the monocotyledonous 

 embryo is either that of a cylinder with rounded ends, or 

 of a more or less lengthened ellipsoid. Sometimes the coty- 

 ledon end is broader ; sometimes, and indeed more frequently, 

 the radicular end is enlarged ; often the small blunt point on 

 the radicular end, at which the suspensor terminates, remains, 

 but before the ripening of the embryo it always projects. 

 The position of the bud (Knospchen) is determined by that 

 of the rootlet ; it appears as a small prominence at one side 

 of the circumference ; this projection is seen in the cotyledonar 

 fissure. In rare cases this cleft is opened its whole length, and 

 its sides allow the first leaflets of the bud to be visible through- 

 out their whole length, as in the case of Ouvirandra, In other 

 cases the sides of the clefts touch in the middle, and separate 

 both upwards and downwards ; and in this case the apex of 



* Die Lehre vom Saamen der Pflanzen. Mit 4 lithographeiten Tafeln. 

 Prag. 1839. 8. 



f Sur les Embryons monocotyledoncs. — Lu a I'Academie des Sciences 

 dans le seance du 1 Juillet 1839 ; Ann. des Sciences Naturelles, Part. Bot. 

 1839, i. 341—361. 



