GOODLATTE : ThE ANATOMY OF PaROSELA SPINOSA 575 



however, the crystals are distinctly rhomboidal and the small cells 

 containing them are always single in the midst of the larger, ordi- 

 nary cells (figure 3). 



Crystals, in greater or less numbers, in the accompanying tissue 

 of the vascular bundles and in the palisade cells, Weyland finds to 

 be a general character for the order, and he further states that those 

 in the palisade cells are rod-shaped throughout the genus Dalea^ 

 while the rhomboidal form also occurs in some species. This 

 proves to be true in the case of Paroscla spinosa. In the layer of 

 cells immediately under the epidermis, and in the mesophyl in 

 general, these rhomboidal crystals are VQvy numerous, especially 

 in the cells surrounding the bundle- strands. The crystals in the 

 palisade tissue are rod-shaped and sometimes partly imbedded in 

 the cell-wall. 



The further structure of the leaf is quite simple. It consists 

 of palisade and spongy tissue, the leaf-edges being rolled so that 

 the palisade cells extend round to the under side. The bundles 

 are concentric, surrounded by a considerable layer of stereome 

 tissue, and around that again, as has been mentioned before, a 

 layer of cells with numerous crystals. Weyland cites the case of 

 Dalea polyadenia^ where these cells with crystal-complexes appar- 

 ently take the place of bast-fibers as strengthening material, and it 

 may very well be that in P, spinosa also they are of auxiliary use 

 in giving rigidity to the leaf-bundles. 



The secretory apparatus of the leaves can best be discussed in 

 connection with that of the stem, as the anatomical character of 

 the two is the same. The stem up to the third year has a highly 

 developed chlorophyl-bearing tissue in the cortex, consisting of 

 five or six rows of palisade cells. The stomata are of the same 

 simple type as those of the leaves, being perhaps rather more 



deeply sunk, in a pit formed by the thickened outer walls. The 

 epidermis has a heavy outer layer of cutin from a very early stage, 

 and this increases until in the third year the entire outer wall, and 

 the radial wall as well, are completely cutinized. As in the leaves, 

 rhomboidal crystals are sparsely scattered through the epidermal 

 cells. The hairs form a thick coating; until the formation of the 



periderm supplants the primary cortex. 



Sanio, speaking of periderm formation in general, states that 



