Glands in the Cotyledons. 437 



with eosiu each cell in the glands of the embryo last 

 mentioned was nucleated (Plate III., fig. 2, gl.). 



The peripheral oval cells of an embryo surround a longi- 

 tudinal layer of cells. The glands of the embryo (Plate III., 

 fig. 2, gl.) arise as rounded epidermal papilla?, and when 

 fully grown they conform to Professor Lawson's description 

 above quoted. The earliest glands observed were seen in 

 an embryo (Plate III., fig. 1), removed from a hardened seed. 

 They measured in height "14, across "13 mm. These em- 

 bryonic glands are sessile. They would seem to be 

 developed before the plumule, and certainly they are 

 developed before the spiral vessels appear. I may here 

 state that the spiral vessels in Galium Aparine are un- 

 connected with the glands of the plant. 



The growth of these embryonic glands is very rapid, for in 

 an embryo whose radicle had only protruded '2 of an inch, 

 the largest glands, i.e., the early glands above referred to, 

 measured in height 'To, across "52 mm., even already 

 attaining almost maximum development, as far as my 

 observations have gone, when as yet the cotyledons and 

 hypocotyl were still in the horny albumen. The plumule, 

 however, was now noticeable. In a seedling 1'3 inch in 

 length, the cotyledonary glands were numerous, and in 

 another (Plate III., fig. 3), measuring 2 inches, the cotyle- 

 donary glands were also numerous, in fact, forming a whorl 

 (Plate III., fig. 4) ; and the two first to appear still keep the 

 lead. In the latter seedling these two glands (Plate III., 

 fig. 4, gl.) measured in height "8, across "53 mm., which is 

 the maximum growth of a cotyledonary gland. 



In a seedling (Plate III., fig. 5), measuring 2-2 of an inch, 

 several of the cotyledonary glands were nucleated in every 

 cell (Plate III., fig. 6). Professor Lawson, in the paper just 

 cited, found that " in Ruhia tinctonim each cell of the gland 

 contains a large green central nuclear body." * The glands, 

 however, referred to were those of the whorls doubtless. 



The leaf glands in Galium Aparine, as far as I have seen, 

 never attain the size of the two first cotyledonary glands. 

 They vary much in size, the largest measuring in height "55, 

 across '22 mm. ; they are mostly smaller. This I consider 

 important. The fact that the adult cotyledon is much 

 * Trans. Bot. Soc. Edin. (1856), vol. v., part i., pp. 5, 6. 



