174 The Botanical Gazette. [May, 
flat areola at its base. In the black and the scarlet oak 
the knob is prominent, and more pointed and conical. The 
acorn-cup is flattish and abruptly contracted to the short pe- 
duncle as it is in the shingle oak, while in the black and the 
scarlet oaks it is more rounded and tapering below, sometimes 
in the scarlet oak being quite conical beneath. The acornsof 
nearly all specimens of Q. tinctoria growing in the vicinity of 
the hybrid were, so far as examined, considerably larger than 
those of the hybrid. Their cup-scales were very pubescent, 
and almost always with wavy, squarrose tips. The meat of 
the acorns was intensely bitter, from a light to a deep yellow 
or orange color, not white or pale as is generally the case with 
the scarlet oak. The interior of the cup was yellow. The 
meat of the acorns of the hybrid was of a pale yellow color 
and was very bitter in taste. By the character of the fruit, 
the color of the outer bark and the rich yellowish-brown or 
russet tinge of the autumn leaves, the neighboring biennial- 
fruited oaks had the characteristics of Q. tinctoria. But the 
leaves were usually deeply lobed, and the inner bark, though 
generally yellow, was sometimes reddish as in the scarlet oak. 
rom all indications, the hybrid seemed to be a cross of Q. 
tinctoria and Q. imbricaria. But the characteristics of Q. 
tinctoria and Q. coccinea sometimes blend so far as to ne 
it difficult to separate them, though from careful study of t 
various forms I believe them to be distinct. If, as many 49 
we regard Q. tinctoria of Bartram a variety of Q. pene re 
Wangenheim, then the hybrids at Willow Spings would 5e* — 
Cross derived from the variety, not the typ 
Quercus rubra occurred not far away in 
woods, but no signs of hybridism were seen between the 
Ce é of i 
the same piece ® — 
red 
oak and the shingle oaks in its vicinity. These were ee : 
tered throughout the woods, but were frequent on i 0. 
the hybrids were found. Two annual-fruited spect | 
alba and Q. macrocarpa, were the only other kinds sh 
but such seem out of the question for parentage. descrip 
The hybrids differed somewhat from the published of the 
tions of Q. Leana which I have seen, combining 7 other 
characteristics of the individual cases described from for 
localities. The number of trees offered a greater i was 
showing the influence of the double parentage. Pr mil 
quite easy to match the leaves with those which I : now if 
in the large collection of the Engelmann herbarium, 
