68 GLANDS. PART I. 



the leaf and petiole, but often also on the other 

 parts of the plant, and supposed to be organs of 

 secretion. This was at least the opinion of Linnaeus, 

 who defined the gland to be " a little tumour 

 secreting a fluid,*" which is in some cases no doubt 

 the fact. From the extreme minuteness or apparent 

 insignificance of vegetable glands, it was long before 

 they attracted the attention of botanists, so as to be 

 distinctly discriminated into species, and described 

 according to their different forms. But this was at 

 last effected by the industry of M. Guettard, a 

 French physician and botanist, who first under- 

 took the investigation of the subject, and charac- 

 terized and distributed them as follows :-f- 

 Varieties. 1st. The Millary Gland. This species is so de- 

 nominated from the supposed resemblance of the in- 

 dividuals contained under it to the miliary glands of 

 animals glands usually described as resembling 

 grains of Millet seed. Sometimes they are crowded 

 together in clusters, as in the Cypress ; or arranged 

 in regular sets, as in the leaves of the Fir. 



2dly . TheVescicular Gland. Glands of this species 

 are small and membranaceous substances resembling 

 transparent bladders. They are found on the leaves 

 of the Myrtle and St. John's-wort. 



3dly. The Scaly Gland. This species has the 

 appearance of thin and minute scales, which are 



* Phil. Bot. sect. 84. f Mem. de 1' Acad, Royal. 1761. 



