SHELDON: KOEBERLINIA SPINOSA. 103 



a conical space at the bottom represents the cell cavity. (Figs. 

 4, 5, plate XXII.) At intervals these picket-like cells give way 

 to large cavities, which they surround and protect by a slight 

 modification at the outer extremity, a curving upward and in- 

 ward, thus making a little dome of from eight to a dozen cell 

 tips. (Figs. 3, 1, plate XXIII.) These, not entirely closing the 

 cavity, leave an aperture allowing of communication between 

 the outer world and the stomatal apparatus within and thence 

 farther beyond to inner tissues. (Fig. 8, plate XXII.) The 

 details of this arrangement, although seemingly complex, are 

 actually simple. The stoma lies at the base of the epidermal 

 air chamber; slight projections of the walls of the guard cells 

 make a shallow stomatal chamber immediately above, and like 

 ones make one below. Beyond the lower lies the large ovoid 

 cavity referred to in the palisade tissue. (Figs. 8, 9, plate 

 XXII, fig. 11, plate XXIII; and for measurements, see table, 

 p. 7.) A curious little Phycomycete makes its home in the out- 

 side stomatal cavities. It occurs in a majority of the stem 

 stomata. (Fig. 7, plate XXII.) There are about 150 stomata 

 to a square millimeter. (Fig. 2, plate XXIII.) In the younger 

 stem a tissue for water storage occurs just outside the peri- 

 cycle. Sometimes this appears to be represented by a single 

 cell only. (Figs. 8, 9, 10, plate XXIII.) The region of spongy 

 parenchyma here stains deep blue with c. z. i., while the pali- 

 sade cells remain yellowish. 



Flower. — The flow^er, cream color to yellow, shows the four- 

 parted arrangement — four very short triangular sepals, green- 

 ish in color; four long, blunt, prominently veined petals, en- 

 closing eight stamens, which show an inequality in length of 

 filament. The anthers are elongate-ovoid, and open on the 

 side. They are attached to the filament at about one-fourth 

 the distance from the base. The filaments are stout and taper- 

 ing upward. The superior ovary is globose in shape, tapering 

 above into a pillarlike style, which in turn tapers slightly at the 

 apex to form the stigma, which is a plain surface surrounding 

 a circular orifice. 



Upon sectioning the ovary longitudinally the numerous 

 ovules are noticed in longi-section ; they appear hanging down 

 from the central placenta. In cross section two cells are seen, 

 and in some parts a suggestion of two side partitions. The 

 ovary wall is cutinized heavily without and within, insuring 



