132 Meyen's Report for 1839 on Physiological Botany. 



almost 9 feet high. The last sprout, or shoot, was §ths of an 

 inch in diameter, and had a pith of £th of an inch in diameter 

 in the thickest part ; the middle shoot was T 7 ^ ths of an inch 

 thick, and had a pith of £th of an inch in diameter ; the oldest 

 and lowest twig had £ths of an inch in diameter, and the pith 

 was -j-^th of an inch thick. In the same twig the pith was 

 not found to be of uniform thickness, but became thinner 

 from the upper towards the lower extremity. 



Of the beautiful anatomico-botanical plates which have 

 been published by M. Link*, we have now received a third 

 number, in which a great many of the most various and 

 well-chosen objects are represented. In this number we see 

 the great advances which the artist, M. C. F. Schmidt, has 

 made as to execution ; some of the plates, particularly tab. viii., 

 may be said to belong to the most successful of their kind. 

 Most of the figures show the structure of the roots of plants, 

 and exhibit the difference therein between root and stem. On 

 tab. viii. is found the anatomy of prickles and thorns, of which 

 we had as yet scarcely any delineations. 



M. Korthalsf has communicated some remarks on the glan- 

 duliferous hairs of Drosera, with which my own observations 

 do not agree. These hairs are said to consist of fibres or ex- 

 tended cells, which are covered by a scarcely developed epi- 

 dermis, and support on the end a small red globule, which in 

 old age falls off, but is also covered by the epidermis. The 

 fibres of the hair extend into the cavity of the apex, but be- 

 fore their entry are somewhat widened. In the interior of this 

 cavity the fibres form a small, egg-shaped, projecting body, 

 and round this columella are found a quantity of small, red, 

 angular particles, &c. 



As in my paper on the organs of secretion of vegetables I 

 have given a description and figures of the glanduliferous hairs 

 of Drosera which are totally different from the above, it is 

 necessary to enter very fully into the subject ; but before I 

 attempt to interpret the statements of M. Korthals, I must 

 state, that I do not know what he understands by u epi- 

 dermis :" this is unfortunately the result of the change and 

 supposed improvement of old, well-known names. In the 

 above memoir I have shown that the hairs of Drosera have a 

 very complicated structure ; the hair itself exhibits in its in- 

 terior a spiral tube which penetrates deep into the apex of the 

 gland, but there is no trace of a cavity in this so-called gland- 



* Ausgewahlte anatomisch-botanische Abbildungen. Berlin, 1839. 

 f Remarques sur les poils du Drosera. Bull.des Sci. &c. en Neerlande, 

 p. 49, Rotterdam, 1839. 



