150 On the Sporophyte of Splackimm luteum. [Dec. 20, 



cortex. Higher up in the seta there is a large intercellular canal 

 formed in the middle of the axile strand of thin- walled empty cells 

 which extends for nearly its whole length. This intercellular space 

 is lysigenous in origin. A similar passage or canal occurs in several 

 other species. 



A longitudinal median section through the umbrella-shaped 

 apophysis shows that the central strand here swells out into a large 

 pear-shaped mass of cells, that in the mature sporophyte contain 

 no protoplasm, and even in the younger states only a very small 

 quantity with small, inconspicuous nuclei. Chlorophyll bodies are 

 absent except in the two outermost layers of cells, even in the 

 youngest specimens observed, and even here there are only a very 

 few. The cells are all thin-walled, and cubical in shape, with no 

 intercellular spaces between them. In this tissue, which may be 

 regarded as a kind of aqueous tissue, large masses of crystalline 

 inorganic matter were frequently found. 



Outside the aqueous tissue there is a quantity of parenchymatous 

 tissue, with numbers of communicating intercellular spaces. The 

 cells all contain large numbers of chlorophyll bodies. This tissue 

 extends into the umbrella-shaped organ. On the upper surface in 

 the proximal region the cells are arranged close to one another, and 

 sh >w a distinct tendency to an elongation of their axes in a direction 

 vertical to the surface, thus forming a palisade tissue similar to that 

 in the tissues of the vascular plants.* This is rendered more striking 

 by a comparison with the parenchyma of the lower surface in the 

 same region, where the cells are much elongated in a direction parallel 

 to the surface, and with very much larger intercellular spaces. The 

 distal region of the apophysis shows that the cells of both upper and 

 lower surfaces have undergone a considerable lengthening in the 

 direction parallel to the surfaces, but that the upper as compared with 

 the lower has still a resemblance to palisade. Stomata are found in 

 considerable numbers in the epidermis of the upper surface, but there 

 are none on the lower. The epidermis consists of a very distinct 

 layer of cells without chlorophyll, the outer walls of which are 

 cuticularised, and have a distinct cuticle. 



A large quantity of starch is formed in the cells of the apophysis 

 by the chloroplasts, each chloroplast containing a number, of separate 

 starch grains. When the apophysis is quite young, at this time 

 being green, immediately on its beginning to become umbrella- 

 shaped, and before the spores ripen, the starch begins to be formed. 

 At a later stage the starch disappears, the starch-forming plastids, 



* Haberlandt (loc. cit.) also makes a comparison between the chlorophyll-contain- 

 ing tissue of the sporophyte of the Mosses and the palisade tissue of true leaves ; 

 but in none of the forms which he investigated is this structure as striking as it is 

 in S. luteum. 



