NortH Haven Sanp PLarns 595 
multicellular hairs. These hairs have been figured by Solereder * 
and are very similar to the hairs of Verbascum Thapsus. The leaf 
contains no colorless water-cells. 
ARONIA ARBUTIFOLIA. — The upper epidermal layer consists of 
large water-holding cells with even outer walls and a thick cuticle. 
These cells are not uniform on their inner walls but some project 
much farther than others into the palisade tissue. The lower 
epidermis is made up of small, green cells. Each bundle is 
enveloped in a parenchyma sheath, and stereome tissue occurs 
below the bundles. Radiating crystals occur in a few of the cells 
of the mesophyl and palisade tissues. The stomata are very 
small and occur on the under surface, where they are protected 
by long curved unicellular hairs. 
SAROTHRA GENTIANOIDES. — Stem has water-holding tissue sur- 
rounding the bundle and extending outward to the epidermis in 
four strands. The stem has large pith-cells in the center, sur- 
rounded by the xylem, which consists of vessels and lignified cells. 
Outside of the xylem there is a thin layer of phloem, beyond 
which there is a peculiar tissue of large irregular cells with rather 
thick walls curiously pitted. This is the water-tissue, extending 
in four strands from the central portion to the epidermis. Be- 
tween these strands are found the palisade-cells. Opposite the 
palisade-cells occur the stomata which are small and not especially 
protected. The water-holding cells have thickened walls, prob- 
ably for the purpose of strengthening the tissues. 
The leaves are opposite and are reduced to mere scales or 
bracts. A uniform epidermal layer covers both surfaces, and the 
assimilating cells occupy the space between with the small bundles 
running through the green tissue. The stomata and epidermal 
cells are much like those of the stem. Large reservoirs are found 
in the green parenchymatous tissue of both leaf and stem. These 
are the pellucid dots common to the Hypericaceae, and are sup- 
posed to contain oil. 
HELIANTHEMUM MAJjUs.— Epidermis of the upper surface is 
composed of medium-sized colorless cells; lower surface has 
smaller cells, most of which contain green coloring matter. Sto- 
mata are abundant on the lower surface, which is densely covered 
*Solereder, H. Systematische Anatomie der Dicotyledonen, 877, f. 784. 1899. 
