ON A NEW CHARACTER IN THE FRUIT OF QUERCUS. 135 
ing attention to it, examining and establishing it in many species of 
our own continent ; and to bim we are especially indebted for the dis- 
covery that two species have been confounded under the name Quercus 
Suber, one of which has annual, the other biennial fruit. 
as From being impressed with the fact that such closely allied plants 
, Should have such distinct periods of maturation, I carefully examined 
this character, to determine both its constancy and also how it might 
be combined with other characters more easily verified or more obvious. 
„At has been examined, not only in every species of which I could obtain 
the fruit, but also in hundreds of individuals of the same species, 
perhaps altogether on two thousand specimens contained in the rich 
herbaria to which I have access. 
The duration of the fruit is mostly easily determined, even from a 
dry branch; it is enough to see if the ripe fruit be fixed to the new 
wood or.to that of the previous year. As the peduncles remain until 
the fruit is mature, this observation is for the most part easy ; but now 
and then specimens occur, especially in those species with evergreen 
leaves, which may mislead or embarrass; but with a little care, espe- 
cially by examining several fruit-bearing branches, these doubts disap- 
pear. When the young fruit-bearing branches of one year do not 
lengthen or branch out the next year when continuing to mature their 
‘acorns, a biennial fruit may be mistaken for annual; but on closer ex- 
‘amination, some difference of colour, size, or pubescence is perceived 
between the branches of one year and those of the next, or a difference 
of consistence in the leaves of each year mdicates the true age of the 
branch. Again, in herbaria, the fruit-bearing branches of the second 
year, whose leaves are lost in desiccation, and being in the axil of a 
former leaf, simulate the peduncles of the year; but in this case, the 
Cicatrices of the new leaves and the pubescence of the branch, when 
compared with that on the principal axis, indicate the truth. n 
the character itself is once ascertained, it is found perfectly constant in 
. each species. 
"Unfortunately the character stands by itself; the result is that two 
closely allied species may have in the one ease annual or in the other 
biennial fruit, as, for example, in the following species :— 
Quercus microphylla, Nee, has annual fruit, and Q. Castanea, Nee 
'Q. mexicana, H. & B.), biennial. 
777 Q. Semani Liebm., Q. Ghiesbregtii, Martens & Gal, and Tlalpu- 
