The White Willow ( Salix alba ) is now covered with its bright yellow 
catkins and makes a charming picture in the landscape. This is the 
largest and the most common Willow tree of New England where it has 
often grown to a noble size and assumed a picturesque habit. It is a 
European tree, and it is of interest that it is the only exotic tree that 
has really become widely naturalized in New England. There are 
many forms of this Willow and the one which has most often established 
itself here is the variety coerulea. There is no record of the introduction 
of this tree into America, but it was probably soon after the settlement 
of the country, for very old trees can be found here, and it must have 
taken a long time for it to have spread as generally as it has done. Oc- 
casionally plants of the Brittle Willow (S. fragilis) may be seen in this 
part of the country, but in some of the middle states it is now completely 
naturalized, having been brought there many years ago to provide char- 
coal for the powder works in Delaware. 
The most interesting plants now in flower in the Shrub Collection will 
be found among the Currants and Gooseberries ( Ribes ). The two yellow- 
flowered American Currants are already in bloom. The better known 
of these, the so-called Missouri Currant ( Ribes odoratum ) was for many 
years a favorite garden plant in the United States and is still found in 
many old gardens. It is a large, broad, very hardy, fast-growing shrub 
with drooping clusters of bright yellow fragrant flowers and lustrous 
black fruits. It owes its popular name to the fact that it was first found 
on the upper Missouri River, and it is now known to occur on the great 
plains from South Dakota to Texas. In many books this plant appears 
as R. aureum , but this name properly belongs to a smaller plant from 
the northwest and the northern Rocky Mountains with more slender 
branches, smaller flowers, and black or orange-colored fruits. This 
species appears to be extremely rare in cultivation. The two plants are 
growing together in the Shrub Collection and the differences in their 
general appearance and in the structure of the flowers can be readily 
seen. Among the Gooseberries already in flower the most interesting 
perhaps are R. pinetorum from the mountains of New Mexico and Ari- 
zona, with bright, orange-red flowers; R. niveum from northwestern 
North America with pure white flowers; R. cynosbati from eastern 
North America, and its spineless variety, R. curvatum from Stone Moun- 
tain, Georgia, with white flowers gracefully drooping on long stalks; 
R. stenocarpum from western China with white flowers, and R. robus- 
tum, a vigorous white-flowered plant of unknown origin but supposed to 
be a hybrid between R. niveum and R. oxyacanthoides. 
The first of the Honeysuckles to bloom this year is Lonicera coerulea , 
a plant with small yellow-white flowers and early ripening bright blue 
fruit. It is one of the most widely distributed of the shrubs of the 
northern hemisphere, being found in numerous forms and varieties in the 
northern part of North America, Europe and Asia. There are several 
distinct forms of this plant now flowering in the Shrub Collection. The 
pink flowered Lonicera gracilipes from Japan and the Fly Honeysuckle 
of northeastern North America, (L. canadensis ) are also in flower in 
the collection where Honeysuckles will continue to blossom for several 
weeks. 
The earliest Barberry in the Arboretum to flower this year is Berberis 
dictyophylla which, although it comes from the warm province of Yunan 
in China, has proved perfectly hardy here. The flowers are solitary or 
