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Collection. The two yellow-flowering American Currants are still the 
most attractive perhaps of all these plants. The better known of 
these, the so-called Missouri Currant ( Ribes odoratum), is still a favor- 
ite garden plant in the United States and is found in many old gardens. 
It owes its popular name to the fact that it was first found on the 
upper Missouri River; it is now known to occur on the great plains 
from South Dakota to Texas. In many books this plant appears as 
Ribes aureum, but this name properly belongs to a smaller plant from 
the northwest and the northern Rocky Mountain region, with more slen- 
der branches, smaller flowers and black or orange-colored fruits; it ap- 
pears to be extremely rare in cultivation. The two plants are growing 
together in the general Shrub Collection and the difference in their 
general appearance and the structure of their flowers can be readily 
seen. One of the Rocky Mountain Currants, Ribes cereum, with small 
white flowers, is as usual attractive at this season. Among Gooseber- 
ries already in flower the most interesting, perhaps, are Ribes pineto- 
rum, from the mountains of New Mexico and Arizona, with bright 
orange red flowers, R. niveum from northwestern North America, with 
pure white flowers, R. Cynosbati from eastern North America, R. steno- 
carpum from western China, with white flowers, and R. robustum, a 
vigorous white flowered plant and probably a hybrid. 
Early Lilacs. Two Chinese Lilacs Syringa affinis, with white flowers, 
and the lilac-colored form of this species, var. Giraldii, are already 
in flower in the Lilac Group. The white-flowered form is largely culti- 
vated in the gardens of Pekin, and the variety comes from the Province 
of Shensi. The flowers of these two Lilacs are fragrant and beautiful 
but their open and irregular habit of growth is not attractive. They are 
certainly valuable, however, for the earliness of their flowers. 
The Oak Collection. This is one of the best times of the year for 
the study of Oak-trees. The unfolding leaves are beautiful, and in 
their color, in the absence or presence of a hairy covering and in the 
character of this covering when it exists, are found characters by which 
the different species may often be easily recognized. These vernal 
characters indeed are less variable than those like the shape of the 
leaves and the size and shape of the fruit which are usually depended 
on for the recognition of Oak-trees. Unfortunately only a compara- 
tively few species can be successfully grown in New England. Of the 
fifty odd species in the United States only twenty-one species and a 
few natural hybrids are hardy in the Arboretum. The Oaks of western 
Europe are hardy but are usually short-lived and unsatisfactory here; 
the few deciduous-leaved species of eastern Asia flourish here but no 
Oak-tree with evergreen leaves can be grown in the Arboretum where 
none of the California, Mexican or Himalayan species can be found. 
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