188 DR. HARLEY ON THE PARASITISM OF THE MISTLETOE. 
BETULA ALBA. 
Ray y4oth of an inch deep and i455th wide, composed of two rows of cells about 
thirty-nine in number. Rays distinct, distant about thrice their width. 
POPULUS NIGRA and SALIX ALBA. 
Ray a thin plate, the ;:3,5th of an inch deep and the اتججاجم‎ of an inch wide, composed 
of a single row of about eighteen cylindrical cells, row sometimes double. Rays almost 
contiguous longitudinally, separated by intervals equalto about twice their width laterally. 
CORYLUS AVELLANA. 
Ray 4isth of an inch deep and the ygsoth of an inch wide, composed of a single row 
of about twenty small cells. Rays discrete, distant about thrice their breadth. 
FAGUS SYLVATICA, QUERCUS ROBUR, and CASTANEA VESCA. 
Ray the 1i15th of an inch deep and the z;4 pth of an inch wide, composed of a single 
row of about fourteen cylindrical cells. Rays discrete, arranged linearly, without over- 
lapping by their edges, distant about twice their width. 
JUGLANS REGIA. 
Ray a broad elliptical fasciculus, the {jth of an inch deep and the zğgth of an inch 
350 
wide, composed at widest part of five rows of large cells, the 55th of an inch broad. 
Rays discrete, but overlapping by their edges, distant laterally about one and a half 
their width. 
ULMUS CAMPESTRIS. 
Ray a narrow elliptical fasiculus, the ;l5th of an inch deep and the j4555th of an 
inch greatest width, composed of a double row of about twenty cells. Rays wide apart, 
distant four times their width in transverse direction, and their width in the longitudinal. 
JESCULUS HIPPOCASTANUM. 
Ray roth of an inch deep and the 355th of an inch greatest width, composed of a 
single row of about six small cells, forming a narrow ellipse. Rays discrete, distant 
iransversely about twice their width. 
TILIA EUROPAEA. 
Rays vary much in size; they form deep plates, some measuring the 4'5th of an inch 
deep and 44'55th of an inch wide, and composed of two, at widest part of three rows of 
cells; others are but the goth of an inch deep and the ysyoth of an inch wide, being 
composed of one long row of oblong cells. Rays distant about three times their width. 
