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VINNIE A. PEASE 
was not observed in the case of any other species examined, under any 
condition. All three curves, that is, for beginning of leaf fall, for 
maximum leaf fall, and for extreme duration, show two maxima, 
the first occurring in the fourth year in all three cases, and the second 
in the sixth and seventh. This is probably due to variations in the 
toxicity of the bog water in different parts of the bog (13). Mature 
specimens from the bog also showed slow growth and small needles, 
but the duration curves were normal and the maxima lay between 
the two sets of maxima in the curves of the saplings. Peat bog 
specimens, both saplings and mature, show an increased leaf duration 
over specimens growing in the open in ordinary soil, the duration 
more nearly approximating that of specimens from a drier climate 
{figs. 6-8). 
10. Rhamnus purshiana DC. Sudworth says that ''in its northern 
habitat the thin large leaves are shed regularly in the autumn, while 
in the drier southern distribution to and through central California, 
the leaves, which are smaller, thicker, and somewhat leathery, often 
persist more or less during late autumn and winter." Frye and Rigg 
(2) state that the leaves are ''deciduous except occasionally on very 
young plants." Sargent (14) says that "in Washington and Oregon 
the leaves fall late in November, while farther south and near the Cali- 
fornia coast they remain on the branches almost all winter, or until 
the following spring." The writer has found that not only do seedlings 
retain their leaves in the Puget Sound region, but that trees in moist 
rich humus under the forest cover, up to ten years old, may retain at 
least a part of their leaves well on into May, when the new season's 
leaves are fully expanded; and these persistent leaves seem not to 
differ in size or texture from those shed in the fall. 
11. Vaccinium parvifolium J. E. Smith. The small plants which 
have germinated on fallen logs under the forest cover are almost in- 
variably evergreen. The slender branches which arise from the root 
crowns of older shrubs also bear leaves which persist from one to 
several seasons. It was thought at first that evergreenness was con- 
fined to branches near the ground, but later several specimens were 
found which bore evergreen leaves from I to 2 meters above the ground, 
on the upper branches. Two distinguishing characteristics present 
themselves in regard to these evergreen leaves: 
(a) The leaves are usually much smaller than the ordinary de- 
ciduous leaves, and are borne on very slender, slow-growing branches. 
