Meyen's Report for 1839 on Physiological Botany. 133 



head. The hairs which form the stalk of the gland are not 

 here, as in most cases, simple excrescences of the upper walls 

 of the epidermal cells, but true excrescences of the substance 

 of the leaf, and appear very early, and therefore one may cor- 

 rectly say, that the whole hair and the head is covered by the 

 epidermis. In quite young organs of this kind it may be 

 seen very distinctly that the gland-head is nothing more 

 than the apex of the compound hair which at a later period 

 thickens, and then stalk and head are still covered by a uni- 

 form epidermis. Afterwards the stalk (that is, the hair) ex- 

 tends to a great length, and thereby all the cells obtain a 

 lengthened form, and the outer layer does not diifer from, 

 those beneath it. 



But with the gland-head it is quite different ; the epider- 

 mis still retains its small cells, is generally filled v/ith red- 

 coloured sap, and exhibits the red angular bodies which M. 

 Korthals mentions. With good microscopes one may see di- 

 rectly under this small-celled epidermis ten or twelve large, 

 elongated, columnar cells, which form the axis of the gland- 

 head ; in their completely developed state they often exhibit 

 in their interior very plain spiral fibres, and let the spiral 

 tubes of the stalk run between them. Even in transverse 

 sections there is nothing to be seen of a cavity in the gland- 

 head, and that none such is present may be better seen in 

 those glands which are found on the edges of the leaves of 

 Drosera rotundifolia. These gland-hairs are (I do not know 

 whether they are similarly formed in other species of Dro- 

 sera) much larger than the others ; the stalk is widened at 

 the extremity like a spoon, and on the side of this spoon sits 

 the glandular organ which effects the secretion. 



It is peculiar to the glanduliferous hairs of Drosera (and 

 herein they agree with the similar organs in Nepenthes), that 

 here and there on the stalks are found small simple glands 

 which consist of two adjoining vesicular cells ; they are filled 

 with green-coloured sap-globules, while the other cells of the 

 stalk generally contain a red sap. It is as if these little glands 

 took the place of the two semilunar cells of the cuticular 

 glands ; sometimes one sees real single cuticular glands with 

 stomata ; in Nepenthes, it is true, the structure of these ac- 

 cessory organs is different. 



I* had the opportunity of procuring a couple of stems of 

 Musa paradisiaca, the flower-stalks of which are (as I have 

 already noticed, when at the Sandwich Islands) so very rich 



* Vcrhandlungen des Vereins ziir neforderung des Gartenliuues in den 

 Preuss, Staaten. xiv. 2tes Heft, lierlin, 18.39, p. 187. 



