1898] BRIEFER ARTICLES : 53 
by reference to recognized pomological groups. If, however, /. rivu- 
/aris is to stand, the date of its publication would give it precedence 
over P. hortulana for that part of the hortudana plums represented ; 
but in view of the tendency to abandon /. hortulana, this does not 
appear to be of very much consequence. 
It is interesting to note in this connection that Prunus Texana,” 
which Scheele erected at the same time as /. révu/aris from some more 
Texas material, has not been heard from since, except to be consoli- 
dated with the latter by Sereno Watson.” 
Prunus Watsoni Sargent.—Quite a number of cultivated forms of 
this species, some of them named and catalogued by nurserymen, 
have recently come under my observation.“ I have also examined a 
quantity of herbarium material. It appears to me that it will be very 
difficult to draw the line between this species and P. angustifolia. 
Even when Sargent’s unabridged descriptions of the two species are 
placed in parallel columns and diligently scrutinized they will be found 
to yield but a single character of distinction. The calyx lobes of ?. 
angustifolia are said to be glandular-ciliate; while of P. Watsoni they 
are said to be eglandular-ciliate ; but this distinction cannot be safely 
applied to the cultivated varieties, as I have had sufficient opportunity 
to observe. P. Watsoni is usually dwarfer, with more zigzag ashy-gray 
twigs, and with more appearance of thorniness, and usually has smaller 
leaves with more finely crenulate margins ; but none of these characters 
will serve for critical discrimination. It may even be found necessary 
in the future to abandon P. Watsoni or to reduce it to a variety of P. 
angustifolia; but for the present this species, name, and description 
seem to be useful in calling attention to a neglected and very interest- 
ng group of native plums.—F. A. Waucn, Experiment Station, Univer- 
sity of Vermont. 
TWO NOTEWORTHY OAKS. 
(WITH PLATES V AND VI) 
I. A NEW HYBRID. 
For three seasons I have been observing an oak which grows in 
the damp sandy woods near the village of Thornton, Ill., six miles 
2 Beitrige zur Flora von Texas. Linn. 21:593- 1848. 
‘Bibl. Index. N. A, Bot 07. 
. 
“The Sand Plums,” Country Gentleman 63 :68. 1898. 
