H0FMEISTER, ON THE HIGHER ORYPTOGAMIA. 401 



higher in Taxus certain of the cells (in the Abietinege 

 and in Juniperus rarely more than one)* of the middle 

 longitudinal string of the cellular tissue of the ovnle become 

 the embryo-sacs (PI. LIX, figs. 10 12). In the ovule of 

 Taxus a short row of cells, usually consisting of three cells 

 of the axile cellular string of the nucleus, is distinguished 

 from the neighbouring cells by their size, and by their 

 containing an abundance of granular mucilage mixed with 

 small starch-granules (PL LXIII, fig. 2). Of these cells 

 sometimes one, sometimes each one of the three is deve- 

 loped into a perfect embryo-sac; Taxns, at first, always 

 exhibits more than one. The cellular layers immediately 

 surrounding the embryo sac are strikingly distinguish- 

 able from the rest of the tissue of the ovule by their more 

 delicate cell-walls, and by the greater concentration of the 

 mucilaginous contents. 



The first stages of development of the pollen of the 

 Coniferse, from the individualization of the mother-cells up 

 to that of the pollen-cells, correspond exactly with the 

 ordinary type of phamogams. The young anther of Pinus f 

 appears at the end of the autumn preceding the flowering 

 season as a short, spatula-shaped scale, convex below. 

 On its under-side, near the base, two oval protuberances 

 are to be seen : these are the lobes of the anthers. Each 

 lobe is filled with a firmly- connected tissue of rather large, 

 delicate- walled cells, the mother-cells of the pollen. Each 

 of these cells contains a spherical nucleus, occupying about 

 one half of the cell-cavity, and having rather transparent 

 fluid contents, and several very small nucleoli. The rest of 

 the cell-cavity is occupied by a gelatinous mucilage in 

 which numerous very small starch-granules are embedded. 

 Tincture of iodine colours this mucilage a pale yellow, and 

 the coagulating fluid contents of the nucleus a deep brown. 

 Two layers of tabular cells form the entire outer covering 

 of the mass of mother-cells ; the layer of horizontally 



* There are trees of Pinus syhestris (one for instance in a marshy spot in the 

 Botanical Garden at Leipzig) which, like the yew, develops two embryo-sacs in 

 most of their ovules. 



f The species which 1 examined were P. sylvestris, maritima, Larix, and 

 balsamea. 



26 



