

STATOCYTES OF THE WHEAT HAULM 



T. L. Praxkerd 



(with FOUR figures) 



The plant statocyte is a cell containing a body or bodies, the 

 statoliths, free to move within it under the force of gravity (i, 5). 

 In the mature wheat haulm, the statocytes are entirely confined 

 to the "nodes" 1 or swellings of the leaf sheaths just above their 



attachment to the stem. Here they occupy more than half the 

 total bulk, forming a definite and continuous tissue, which I have 

 previously termed statenchyma (5). 



Fig. 1 makes the anatomy in this region clear. The swollen 

 leaf sheath is bordered within and without by an epidermis suc- 

 ceeded by a few layers of collenchyma of the type described by 



■ 



Haberlandt as lamellar (2, p. 156). Between these layers the 

 fibrovascular strands, consisting mainly of slightly lignified fibers, 

 are arranged in an irregular ring, varied occasionally by smaller 

 strands of similar fibers unaccompanied by, or surrounding a trace 

 only of vascular tissue. The whole, or nearly the whole of the 

 ground tissue is transformed into statenchyma, more highly 

 differentiated than usual, since the statoliths are of two kinds. 

 The more general type of statolith (the starch grain) is found in 

 groups of cells occurring adaxially to the vascular strands. These 

 sometimes form only one or two layers, but occasionally are more 

 extensive, and even reach the internal collenchyma (fig. 1). All 

 the other statocytes, composing by far the greater part of the 

 ground tissue, contain crystal statoliths, and are best developed 

 internally to, and on the flanks of the fibrovascular strands. 



This position of the statenchyma within the vascular ring is 

 unusual, although not without parallel. 2 A crystal statolith, how- 

 ever, is probably extremely rare, for, although expecting it, I have 



x The term "node" is used throughout the paper in this sense. 



2 In 191 1 I figured (3) the statocyte pith of Hottonia paiustris, and since then 

 other cases have become known to me of the conversion of the pith in whole or in 

 part to statenchyma. 



Botanical Gazette, vol. 70] 



[148 



