80 HARSHBERGER— LEAF STRUCTURE OF [April 23, 



depressed (Plate IV, Fig. 3a). The loose parenchyma is prominent, 

 as also the single row of palisade cells. 



Strophostyles helvola (Plate IV, Figs. 4 and 4a). — This annual, 

 trailing, leguminous herb has ovate to oblong-ovate leaflets with a 

 more or less prominent rounded lobe toward the base. The flowers 

 produced from June to September are greenish-white to purplish. 

 In the hot sun, the leaflets assume hot-sun positions. The cells of 

 the upper epidermis are thin-walled with the outer wall slightly- 

 thickened. Two well-marked rows of palisade cells are present, 

 while the stomata are at the surface (Fig. 4a). The loose paren- 

 chyma is clearly seen and the lower epidermis consists of thin- 

 walled cells. 



Lathyrus maritimus (Plate IV, Figs. 5, 50, 7, ya). — The beach 

 pea is a perennial, stout, trailing plant, as it occurs on the dunes 

 of New Jersey. The coarsely toothed stipules are nearly as large 

 as the leaflets, which are 6-10 in number, ovate-oblong. The leaf- 

 lets assume hot-sun positions, especially those near the surface of 

 the sand. The flowers are large and purplish, appearing from June 

 to September. The epidermal cells on both the upper and lower 

 surfaces of the leaflets are thin-walled with a slightly thicker outer 

 wall, rounded, almost chain-like in arrangement. The loose paren- 

 chyma is compact and there are two rows of palisade cells. 



Cakile edentula (Plate II, Fig. i ; Plate IV, Figs. 6 and 60). — 

 The sea rocket is a fleshy annual growing on the upper sea beaches 

 and in clumps on the sand dunes (Plate II, Fig. i). Its fleshy 

 leaves are obovate, sinuate and toothed. The epidermal cells are 

 large with outer walls slightly thickened, while the parenchyma cells 

 are large and directed vertically with the exception of a few central 

 cells, so that the leaf structure is that of a typic diplophyll. The 

 stomata are at the surface (Fig. 60). The xerophytic structure is, 

 therefore, seen in the fleshy character of the leaf and in the arrange- 

 ment of the internal parenchyma cells. 



Solidago sempervirens (Plate IV, Figs. 8 and ^a). — The seaside 

 golden-rod is a smooth, stout plant 0.3-0.5 m. high. The somewhat 

 fleshy leaves are entire, lanceolate, slightly clasping; the lower ones 

 are oblong-lanceolate, obscurely triple-nerved and all of the leaves 



