45 



Ujwn Albumen^ especiallij that of Lccjuminosce^ ht/ Doctors 



Schldden and Vogel. 



(Abstracted from the Germau.) 



That the presence or absence of albumen in plants is of 

 great importance, has been shown by the researches of Mirbel, 

 Brown, and Brongniart ; and it has been made by Lindley to 

 form an important element in the grouping and distinguishing 

 natural families. The foundations of the science of embry- 

 ology in plants were laid by Malpighi, but it has been neg- 

 lected by the followers of Linnaeus, who, in fact, have degraded 

 a great science to a pretty game for filling up idle hours. 

 Brown was the first of the present day to revive and carry out 

 Malpighi's views, which had been more or less misunderstood 

 by those who had followed him, 



1 . Or tlic formation of A Ibumen. — The essential parts of 

 the ovule are the nucleus and embryo-sac, which are never 

 absent. The integuments are uncertain ; where the integu- 

 ments unite with the nucleus, the parts is called chalaza. In 

 Canna and most Compositaj this union is very extensive, and 

 the integuments are only seen at the point of seed. In the 

 embryo-sac, a portion of cellular tissue is often developed and 

 again absorbed ; this is Mirbel's quartine. In seeking for 

 albumen, the positions in which it might be expected to be 

 found are — 1. in the inteouments — 2, the nucleus — 3. the em- 

 bryo-sac — 4. the region of the chalaza. It is, however, never 

 found in the integuments, but in all other parts. In Mono- 

 cotyledons, albumen is mostly found in the embryo-sac, reduc- 

 ing the walls of the nucleus, by pressure, to a thin membrane. 

 It is difficult to say whether the membrana interna of the ripe 

 seed is formed from the integumentum internum of the ovule, 

 from the membrana nuclei, or from a combination of both. 

 It may be sometimes formed from each. In the process of 

 growth the embryo-sac becomes filled with cellular tissue, 

 which produces the albumen. Examples may be seen in Phi- 

 lydrum lanuginosum, also in all Aroidea?, Graminea?, Cype- 

 raccae, Liliacese, Palmacese, &c. ScitamincEe are an excep- 

 tion, for excepting Canna, they develope their albumen in the 

 nucleus, as in Maranta gibba. The development of Canna is 

 altogether peculiar. The albumen is developed in the region 

 of the chalaza, and although five layers can be distinguished 

 they can none of them be identified. In Dicotyledons the 

 G—Juhj, 1842. / 



