410 HOFMEISTER, ON 



increases in size. Thuja and Cupressus behave in just the 

 same manner. 



In all the Coniferae, after the embryo-sac has become 

 entirely filled with cellular tissue, a considerable growth 

 commences in certain cells situated close under the mi- 

 cropylar end of the endosperm, which growth sets in 

 even long before the cell-multiplication in the neighbouring 

 cells has ceased (PI. LX, figs. 5 7). Thus the essential 

 part viz., the large spherical cell of the so-called cor- 

 puscula is differentiated from the surrounding tissue. In the 

 Abietineae each corpusculum is separated from the next by 

 at least one, often by several cellular layers (PI. LX, figs. 6, 7 ; 

 PL LXII, fig. 3). The corpuscula of Juniperus (PL LXV, 

 figs. 1 3, 9), Thuja and Cupressus, immediately adjoin 

 one another. In Taxus two corpuscula are sometimes in 

 contact ; most of them are separated from one another by 

 thick layers of cellular tissue (PL LXIV, figs. 1, 2). 



The corpuscula of Taxus are shortly ellipsoidal, those of 

 the Abietineae are ellipsoidal and elongated ; those of Juni- 

 perus and Cupressus are long and prismatic, with blunt 

 edges and small ends. The formation of corpuscula is not 

 always limited to the micropylar end of the albuminous 

 body. In Juniperus especially, numerous irregularities 

 occur : sometimes there is only a remarkable increase in 

 size of the deeply seated cells of the endosperm, some- 

 times a corpusculum is formed complete in all its parts and 

 opening in the middle of one of the lateral surfaces of the 

 endosperm. 



The apex of each corpusculum is at first only separated 

 by a single cell from the inner wall of the upper arch of the 

 embryo-sac. In most of the Coniferae this cell divides twice, 

 and produces four cells lying in one plane which are distin- 

 guished from the neighbouring cells by their contents 

 being thickly mucilaginous and having many granules ; this 

 is the case in Pinus sylvestris (PL LX, fig. 8), Pinus Strobus, 

 austriaca, maritimus and Mughus ; in Abies Larix and bal- 

 samea ; in Taxus baccata (PL LXIII, fig. 11), and cana- 

 densis (PL LXIV, fig. 1) ; in Juniperus sibirica (PL LXV, 

 figs. 2, 9) and communis; in Cupressus pyramidalis and 

 Thuja orientalis. In Pinus Fraseri I found the four apical 



