99i 
Medullary Rays of Quercus . 
A, B, C, refer to different annual rings of one specimen ; the second to the 
sixth columns refer to the spring-zone and record respectively the mean 
diameter (V) of the innermost vessels, their maximum diameter (F), their 
maximum tangential distance (D) apart (or those marked with an asterisk 
the maximum tangential distance from a large medullary ray), the maximum 
distance apart (D) divided by the mean diameter ( V) of the vessels, and 
the minimum diameter of the vessels; the seventh to the ninth columns 
refer to the outer zone of the annual ring and record respectively the mean 
(v), minimum, and maximum diameters of the vessels; the tenth column 
gives the maximum diameter (M) of vessels in the middle zone ; the eleventh 
column gives the maximum diameter (F) of vessel in the spring-zone 
divided by the maximum diameter (M) of vessel in the middle zone ; the 
twelfth column gives the mean diameter ( V) of the vessels in the spring- 
zone divided by that {v) of the vessels in the outer zone. 
The thirteenth to eighteenth columns give the resultant order as 
calculated respectively by the columns 12 (small measurements), 12 (large 
measurements), 5 (small measurements), 5 (large measurements). Measure¬ 
ments in reference to Q. semecarpifolia , Q. fenestrata are not given, and 
are incomplete in the case of Q. tomentella. 
An examination of columns 1 and 13 to -18 show that the order 
of succession of the species when judged by the different criteria does 
not exactly agree. This is no doubt partly due to the limited number 
of observations, but it is probably also an indication that the various kinds 
of changes have not travelled along parallel lines in evolution. Yet when 
the last six columns are averaged the order attained agrees largely with 
that assigned by inspection (the greatest exception being Q. virginiana). 
Order when judged :— 
Name of species and habit. 
By inspection. 
By columns 
By columns 
By columns 
13-18. 
16-18. 
SE. Q. Emoryi 
1-4 
i 
1 (1-6) 
1 (i- 5 ) 
SE. Q. arizonica 
1-4 
2 
2 (1-6) 
2 (i-5) 
SE. Q. dttmosa 
1-4 
4 
3 (1-6) 
3 (i- 5 ) 
SE. Q. hypoleuca 
1-4 
6 
4 (1-6) 
4 (i- 5 ) 
E. Q. chrysolepis 1 
5 
3 
5 (1-6) 
5 (i- 5 ) 
E. Q. densijlora 
6 
5 
6 (1-6) 
6 
SE. Q. Engelmanni 
SE. Q. virginiana 1 
7 
7 
7 
8 
8 
12 ( 13 ) 
11 (12) 
11 (12) 
SE. Q. agrifolia 
9 
8 
9 
9 
E. Q. tomentella 
(u) - 
(11) 
SE. Q. semecarpifolia 
(io) 
' — 
— 
E. Q. glauca 
ii 
IO 
8 
7 
E. Q. lamellosa 
12 
13 (14) 
12 (13) 
12 (13) 
E. Q. incana 
*3 
9 
10(11) 
10 (11) 
1 The anomalous position of the evergreen Q. chrysolepis and the sub-evergreen Q. virginiana 
would vanish if, as I cannot help suggesting, the wood specimens of the two had been inadvertently 
interchanged in Professor Sargent’s collection or before reaching me. 
3 T 2 
