1915] St. John,— Rumex persicarioides and its Allies 79 
Regarded from this angle, it can be seen that all our known stations 
for Rumex maritimus var. fueginus lie near the line of the Cretaceous 
or early Tertiary sea coasts, and it is significant that a few other 
plants have a somewhat similar, but not identical distribution. Dis- 
tichlis spicata, credited to Patagonia by Macloskie ! on the basis of a 
report by John Ball, but not seen by me, is found otherwise only in 
North America; but it there extends down the Atlantic coast. to 
Florida and appears on some of the Antilles and in Mexico. Ranun- 
culus Cymbalaria has a range in North America somewhat similar, 
but in South America is found in the Andes as far north as Ecuador. 
This species, however, is somewhat circumpolar in distribution, 
occurring in widely separated sections of Asia. 
However strong the evidence from the animal kingdom may be, 
we do not seem to find sufficient confirmation in the plant kingdom 
to demonstrate conclusively that the discontinuous distributions, 
such as that of Rumex maritimus var. fueginus, must have been brought 
about by a Cretaceous or early Tertiary land bridge outside the present 
limits of America, as is argued by Scharff. Until we know better the 
flora of western South America it seems safer to infer that the Rumex 
may sometime be found, like Ranunculus Cymbalaria, among the 
Andes of Central, or northern South America, and to think that, of 
the two interpretations above outlined, at least in the case of the 
higher plants, the one advocated by Hooker, Gray and many others, 
is the more probable explanation. 
In arid parts of western America,— Utah, Lower California, and 
eastern Washington 
fueginus has been found, which has the bristles of the valve nearly 
or entirely obsolete. Although but scantily represented in herbaria 
this seems worthy of recognition. It is possible that this is the plant 
described by Watson as R. salicifolius var. (?), Wats. Bot. King Exp. 
314 (1871), as is implied by Trelease,? but Watson's material has not 
a plant closely simulating R. maritimus var. 
been seen by the writer. 
RUMEX MARITIMUS L., var. athrix, n. var., R. maritimum, var. 
fueginum foliis lineari-lanceolatis cordatis vel basi truncatis simulans 
sed differt setis valvularum obsolescentibus vel absolute deficientibus. 
— Tyrer, M. E. Jones, no. 5839, clay, altitude 5400 feet, Vermilion, 
Uran. 
1 Macloskie, Princeton Exped. to Patagonia viii. pt. 5, sect. 1, 218 (1904). 
2 'Trelease, l. c. 94. 
