1152 



' On the Nucleus of the Characeae ; by Al. Braun ;' being a transla- 

 tion by Mr. Henfrey. 



' Note on the Parasitism of Comandra umbellata ; by Asa Gray.' 

 Extracted from ' Silliman's Journal.' 



In North America, the genus Comandra replaces the European 

 genus Thesium. After giving Mr. Mitten full credit for his important 

 discovery of the parasitism of Thesium linophyllum, a full account of 

 which was published in Hooker's ' Journal of Botany,' and in the 

 ' Phytologist,' Dr. Gray goes on to describe a similar discovery as 

 regards Comandra. " My esteemed correspondent, Mr. Jacob Stauf- 

 fer, of Mount Jay, Lancaster county, Pennsylvania, has recently sent 

 me fresh specimens of Comandra umbellata with its elongated and 

 woody subterranean stems, giving off numerous roots, the branches of 

 which are often expanded at their tips into a small tubercle or sucker, 

 which is implanted by its disk-like surface upon the bark of adjacent 

 roots, principally of shrubs. The foster plants in the specimens com- 

 municated, are blueberries and huckleberries {Vaccinium vacillans 

 and Gaylussacia o^esinosa). Mr. StaufFer's specimens are accompa- 

 nied by a neat drawing, illustrating the mode of attachment. This I 

 would gladly forward for the engraver ; but it will suffice perhaps for 

 the present to say that the attachment is similar to that so clearly 

 exhibited by Mr. Mitten, in the plate which accompanies his article ; 

 only that the rootlets in Comandra are from subten-anean stems, and 

 the suckers, so far as I have examined, do not appear to penetrate the 

 foster root deeper than the surface of its wood. 



" Since the above was in type I have received from Mr. Stauffer 

 the announcement of his discovery of the parasitism of Gerardia flava, 

 accompanied by a drawing which exhibits it, and a specimen which 

 plainly shows the attachment. The numerous branches of the root 

 are not only attached by disks or suckers to the bark of the root of 

 the foster plant (in this case either white oak or white hazel), but are 

 also implanted on each other, forming parasitical anastomoses." — 

 Silliman's Journal, Sept. 1853. 



The subject of root-parasitism, which has been established so com- 

 pletely in Orobanche, Lathraea, Thesium, and now in Comandra and 

 Gerardia, and proof of which has hitherto so completely failed in 

 Monotropa, is one of surpassing and absorbing interest. Decaisne is 

 said to have detected it in Pedicularis and Melarapyrum ; but his 

 conclusions have been the objects of some controversy, and much dif- 

 ference of opinion. It is well known to cultivators that all attempts 

 to grow the Rhinanthaceous plants, otherwise than amid a host of 



