UTRICULAR STRUCTURES. 175 



plants have not this property. But the objection here 

 applies that the mucilage-utricles rotate already before 

 the spinous coat is observable on them. I do not think, 

 therefore, that this has anything to do with the motion, 

 and would rather conjecture that it is to be explained 

 in the same way as the outer membrane of the pollen- 

 granule. 



5. Proliferous utricles (Brutblaschen.) 



I give this name to those utricles in which, as in 

 Caulerpa, the chlorophyll- and starch-granules originate.* 

 I formerly called them " mucilage-cellules" (schleim- 

 zelkhen], but this name now requires alteration in respect 

 to the rest of the nomenclature. Metteniusf saw the 

 proliferous utricles in the radical hairs, and in the hairs 

 of the upper surface of the leaf in Salvinia. 



According to Hartig } the chlorophyll-granules originate 

 in the so-called euchrome-cells, one kind of the so-called 

 ptychodal utricles. The manner in which the researches 

 were instituted, however, does not appear to me to afford 

 the requisite guarantee, for results which can be depended 

 on. It therefore still remains uncertain whether and 

 where the proliferous utricles are found in the Phanero- 

 gamia. 



The proliferous utricles first appear as homogeneous 

 globules of mucilage. When they become larger, we 

 detect a membrane on them, and mucilaginous contents, 

 coloured yellow or brown by iodine. According to 

 Mettenius, the utricles originate as minute amorphous 

 granules. If this be intended to signify those minute 

 homogeneous globules of mucilage, and not actual gra- 

 nules, it agrees with my observations. The globules 

 differ from the mucilaginous granules by their regular, 

 perfectly spherical form, their wholly smooth surface, and 



* Nageli on Caulerpa, Zeitschr. fiir wiss. Botanik., Heft i, pp. 184 190. 

 f Beitrage zur Kenntniss der Uhizocarpeen, p. 51, pi. ii, figs. 42, 43. 

 I Das Leben der Pflanzcnzelle, pp. 8-10. 



