129 
Shrinkage of Leaves in Drying.* 
(PLATE 184.) 
While it is well known that foliage undergoes a shrinkage in 
the ordinary process of drying, the amount has not heretofore 
been considered great or perhaps worthy of mention. The 
Solandi process of sun printing previously considered (see page 
485 of the Bu.Letin Vol. 20), permits of an accurate and rapid 
recording of the shrinkage of foliage, and by means of it the ac- 
companying outlines (Plate 184) are obtained and figures deduced 
below. 
Fresh leaves were measured by securing sun prints as soon as 
Convenient after being gathered. They were then put in press 
and dried in the ordinary way for making herbarium specimens. 
After they were fully dried, a second print was taken or the leaf 
itself used, and from these two measurements the comparisons are 
made. It is, of course, an easy matter to take a print each day 
up to the time the leaf is dry, and in that way determine when in 
the period of drying that the greater shrinkage takes place. 
In order to determine what portion of the leaf surface under- 
went the more contraction, many of the samples of leaves were 
first brought with the surface upon a “card” used by hostlers in 
Combing the manes of their animals. In this way small holes 
Practically equidistant were made in the blade, and by means of 
these, the central ones being taken as fixed points, the shrinkage : 
for all Surrounding areas is determined. . 
The leaves of endogenous plants shrink less than those of the 
€xogens and very little in length. Thus a leaf three inches long 
of a cultivated cypridpedium gathered in its full vigor loses but — 
* small fraction of an inch in its length, and the same is true of 
fresh Steen leaves of a grass (Panicum) shown at a, while a five | 
nch long leaf of lily-of-the-valley (6) shrunk largely in width, but 
i 
almost none in length. But a somewhat similar leaf (Helianthus), eo 
8 to shape and total area, shrank greatly in all directions ‘and-lost 
27 Per cent. of its original surface. The common plantain (Plantago- . 
“aor) bears a large leaf which exhibited a striking amount of 
_ “Read before Section G., A. A. A. S., Madison, Wis. August, 1893. 
