58 



that the amylum in fresh Lichens was coloured blue by iodine, 

 and in fact lichen-amylum does not exist in the form of glo- 

 bules in Lichens, but forms the membranes and the contents 

 of their elementary organs. 



In a subsequent note* read by M. Payen before the So- 

 ciete Philomatique, he observes that he had been able to see 

 with the microscope the amylum of the Iceland moss united in 

 small balls ; M. Payen however did not notice that the septa 

 of the cells of those plants are also coloured blue by iodine. 



Monographic revisions of various Families of Plants in a 

 Physiological point of view. 



From M. Ungerf we have received a very excellent work 

 on parasitic plants, which especially treats very fully of the 

 inrooting of the parasites on the stock plants. The inquiry 

 relates to parasites, which are independent and individualized 

 plants, which although not independent of other plants at 

 their origin, are nevertheless so in the duration of their life, 

 and in which they are, as it were grafted, and from which they 

 almost exclusively derive their nourishment. From this pe- 

 culiar vital process, more than from their form and their struc- 

 ture, these plants are united into a distinct group. A want of 

 roots or root-like organs is peculiar in a higher or lower de- 

 gree to all parasites, and M. Unger observes, that although 

 we find in some of the more perfectly developed species a true 

 rhizoma, nay, even ramified roots, this indicates far more the 

 evident general tendency of nature to attempt variations of 

 formation in every possible manner, within the limits of cer- 

 tain vital laws, than a deviation from the general rule. 



The vast abundance of materials at M. Unger's disposal in- 

 duced him to form a division of the parasitical plants into va- 

 rious groups, founded on the mode of connexion existing be- 

 tween the parasite and its stock. Nine such groups are esta- 

 blished, the genera forming them enumerated, and their in- 

 rooting in the stock plants more or less completely described. 

 The following are the groups. 



1. The parasite originates immediately upon the wood of 



L'Institut de 1837, p. 145. 



f Annalen des Wiener Museums, vol. ii. p. I. 



