IJKSERVE CELLULOSE. 5 



amount of reserve cellulose. When much reserve cellulose, and comparatively little 

 other reserve, is present, the seeds are almost stone-hard when dry, and comparable 

 with the ivory-nut, vvhei'e maiuiose-yielding reserve cellulose was first discovered. 



Only in exceptional cases is starch associated with these other reserve matters 

 in the endosperm. This is true in Paris and Trillium, and, in Ijoth of these seeds, 

 the reserve material on the walls is inconsiderable. 



Interesting resemblances between the seeds of related genera, are apparent, as 

 well in the outward appearance as in the l)ehavior toward microchemical tests. 

 Paris and Trillium cited above illustrate this. 



Of the twenty-eight genera studied these two are exceptions to the rule that in 

 Liliaceae, Amaryllidaceae, and Tridaceae, reserve cellulose forms an important part of 

 the nourishment stored in the seed for the young plant, and that starch is not 

 present as a reserve matter. 



It should be mentioned that tlie association of starch as a reserve witli reserve 

 ci'lhdose in seeds of Paris quadrifolift was (Irst pointed out by Reiss.' 



MicRocnEMicAL BEIIA.VIOU OF Reseuve Cellulose. 



Cellulose has been defined as a carbohydrate of the comjiosition (C,;Hi„0-)„, 

 which is dissolved in cupranmioiiia. and is colored Idue with chloroiodide of zinc, with 

 iodine, and with sulphuric acid. It has, however, been found necessary to distin- 

 guish various modifications of cellulose occurring in the cell membranes of plants. 



Ordinary cellulose of cotton-fibers and cell membranes of young roots have a 

 certain well-known action in the presence of iodine solutions, acids, caustic alkalies, 

 coloring fluids, etc. Lignified membranes, suberized walls, etc., [)resent certain 

 marked characteristics, which are none the less clear in the typical cases because 

 gradations between classes appear. 



It seems possible to define the behavior of the reserve cellulose, as found in the 

 seeds of Liliaceae, in the presence of microchemical tests, even though certain minor 

 differences appear in the different seeds. 



Reserve materials of the cell wall have jjeen divided by Tschircii" into two 

 classes, cellulose and vegetable mucilage. These, he says, are closely related, grada- 

 tions between the two being found. Under cellulose he names two forms, the first 

 that of Plioemx dactylifera and PhyteJephas macrocarpa, which he terms ''reserve cellu- 



' Reiss, Ui'ber (lie natur iler reservei'dlnldso. Lnndw. -A. Tscliircli, Aiisrwamlti' iiHaiiziiiaiiiitniiiic, s. -fa:!. 



jalirluiihiT, IS, s. 74(1. 1S80. 



