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1 9 20] PRA NKERD—S TA TOC J ' TES 149 



■ 



never discovered it elsewhere, notwithstanding careful search in 

 more than a hundred plants, widely differing in habit and systematic 

 position. 



The crystal-containing statocytes are nearly twice as broad 

 as they are long, that is, they are compressed in the axial plane. 

 In shape they are irregularly cylindrical and hence circular 

 in transverse section, while the longitudinal walls are generally 

 more or less gabled (cf. fig. 3). The shape and arrangement of 

 these cells thus allow easy extension of the tissue on bending of 

 the node. The average diameter of the cells is about 55 p, and thfe 

 height about 30 £i. The walls are pitted, which is best seen in 

 transverse sections showing the flat horizontal walls in surface 

 view. Each contains a relatively large nucleus (about 18 /x 

 diameter). In one case two nuclei were seen, although to what 

 extent this is a general phenomenon in the wheat plant has not 

 yet been determined (cf. 4, note at end). The crystals usually 

 occur singly in the cells, and when there are several this is probably 

 due in some cases to fracture. They apparently belong to the 

 tetragonal system (10 // diameter), and occur as prisms, pyramids, 

 spherical aggregates, combinations of these, or in less definite 



forms (fig. 4). Hydrochloric acid dissolves them at once, but they 

 are unaffected by glacial acetic acid and various stains. From 

 these facts their chemical composition is judged to be calcium 

 oxalate. 



The am 



the 



much 



crystal statocytes (fig. 2). Each possesses a nucleus (about 10 /i 



» starch grains 

 grains are simp 



diameter. Mo\ 



made 



of the mature wheat plant. The latter occur in the pith of the 

 stem, but are not free to move; and, except of course in the grain, 

 only traces of imbedded starch have occasionally been found. 

 Preliminary work on the seedling and young plant indicates that 

 statolith starch exists throughout its life and appears in the same 

 localitv that ia it is constant in time and space, while imbedded 



