210 Trans. Acad. Sci. of St. Louis. 



striated zone the pore-canals enlarge; the light line occurs 

 above the middle. The cells contain some pigment. 



Osteosclerid. Thick-walled cells are 30-35 /a long ; the upper 

 and lower cross-bars nearly equal; small intercellular spaces 

 between the bars. 



Nutrient. Consists of thick-walled sclerotic cells ; the 

 walls of the outer part are darker colored than the interior. 



Inner integument. The inner, coat is much compressed and 

 can be made out only on the addition of chloral hydrate to 

 the section. It consists of a row of quadrangular cells 

 followed by thinner-walled osteosclerid-like cells and ducts. 



Nucellus. The nucellus is much compressed and consists 

 of elongated cells with granular contents. 



Endosperm, The cartilaginous endosperm consists of thick- 

 walled cells which on the addition of water are converted 

 into mucilage ; the water causes the secondary walls soon after 

 to become dissolved, leaving large intercellular spaces. The 

 lower part of the endosperm consists of cells which are 

 smaller, with less thickened walls. This is much com- 

 pressed. 



Embryo. The cells of the first row are elongated and 

 smaller than the underlying. Numerous procambial vessels 

 in the cotyledons, and, in some cases, well-formed spiral ducts. 

 Palisade cells absent. Cells contain fat and protein, but no 

 starch. 



Gleditschia, Clayton. ( Gleditsia^ L.) 



Because of the more easily accessible material, several 

 species have been studied. Schleiden and Vogel, Huss, Harz, 

 and Chalon made an examination of the following species: 

 G. caspica, Desf., G. triacanthos, L., G. latisiliqua, Lodd., G. 

 indica^ Pers., and G. macracantha^ Desf., but only with ref- 

 erence to endosperm. Nadelmann gives a very full account 

 of the mucilaginous endosperm of G. caspica. 



All of the species are characterized by having a smooth hard 

 testa; copious cartilaginous endosperm which on the addition 

 of water becomes mucilaginous ; sclerotic parenchyma ; nutri- 

 ent layer strongly developed and, as in Gymnocladus^ an inner 

 testa occurs. Cotyledons agree with Cassia and Gymnocla- 



