MAGN0LIACE2E. 169 



are formed of peculiar cells, elongated horizontally, and becoming 

 deformed or bent where they come in contact with the medullary 

 sheath. They owe their coloration to their contents ; and the 

 outer wall is at once distinguished by the numerous canals by 

 which it is perforated, by the way it refracts light, and l)y its great 

 thickness. Though this character varies from one species to another, 

 and even in a single species, according to the conditions under which 

 it grows, we may rank these peculiar cells in the category of those 

 termed ' Sfeinzellen in Germany. Drimi/s and Schizaudra present 

 similar ston?/ cells [Fr. cellules pierreuses\ in their medullary paren- 

 chjana ; but their arrangement presents characteristic differences. 



" In the pith of a young branch of Drunt/s Winfcri, or any of 

 its varieties, especially D. granatensis, we here and there see cells, 

 near together or separated, which gradually lose the primitive thinness 

 of their walls. Their form varies somewhat with age, for they may 

 have all their diameters equal, or become vertically elongated and 

 fusiform as they grow older. Their walls become thickened by 

 internal increments only, for the numerous cylindrical openings by 

 which they are perforated early cease to be of uniform calibre 

 throughout. The thickening is less marked towards the two orifices 

 of the canal, and especially the internal one, so that soon each canal 

 has the form of a cylinder, widening out into a cone towards each 

 orifice. Hence results the formation of a fusiform cavity by the 

 union of two canals belonging to neighbouring cells, whose orifices 

 exactly correspond ; hence also the areolate appearance of the punc- 

 tations when seen from above, like that presented by Conifers. The 

 contents of these stony cells are of a yellow or brown tint in 

 specimens brought from their native country. These cells, then, 

 are physiologically comparable to those which form granular aggre- 

 gations in the cortical parenchyma, 



"The pith of Schizaiulra is often of a uniform green tint, due, in 

 the first place, to the green matter contained in the ordinary cells of 

 its parenchyma. It is further studded with stony cells, with deeply 

 coloured contents, arranged either in vertical rows or without any 

 apparent order. Some Sphcerostemas present peculiarities in these 

 vesicles which demand a special description.' Olteu these cells, 



' In these nearly cylindrical cells we find on crystallization, formed of very unequal irrcirul.irly 

 the inside of the walls a sort of nearly colourless facetted fragments of high refractive index, ami 



