44 
begin to bloom until most of the varieties of the common Lilac have 
faded. It also promises to be a successful parent in producing new 
forms by crossing it with varieties of the common Lilac. It has already 
produced in France by crossing it with the Hungarian S. Josikaea a 
race of beautiful hybrids to which the name of S. Henryi has been 
given. One of the handsomest of these hybrids, S. Lutece, covers itself 
every year with large open clusters of red-violet flowers and is per- 
haps one of the handsomest of all Lilacs. 
Spiraea Veitchii is the last of the white-flowered Spiraeas to bloom 
here. It is a shrub as it grows in the Arboretum from eight to ten 
feet high with numerous slender stems and gracefully arching branches 
which by the middle of July are covered from end to end with broad 
flower-clusters raised on erect stems. It is one of the best plants in- 
troduced by Wilson from western China, and by many persons it is 
considered the handsomest of the genus as it appears in the Arboretum. 
Brooms. By moving them from the low ground of the Shrub Collec- 
tion to the comparatively dry warm border on the southern slope of 
Bussey Hill it has been shown that a much larger number of species can 
be successfully grown in this country than was formerly supposed when 
only a few of these plants were cultivated in the Arboretum. There are 
now at least a dozen species and varieties of these plants well estab- 
lished on Bussey Hill and many of them have flowered profusely this 
year. 
Tree Lilacs. As the flowers of the late flowering group of Lilacs 
fade the earliest flowers of the so-called Tree Lilacs begin to open. 
There are three of these Lilacs which bear large clusters of white or 
yellowish white flowers which have the disagreeable odor of the flowers 
of the Privet, and, like those of the Privets, the leaves fall in the 
autumn without change of color. The first of these plants to bloom, 
Syringa amurensis, a native of eastern Siberia, is a shrub twelve or 
fifteen feet high, with dark close bark, broad thick leaves dark green 
above and pale below, and short, broad, unsymmetrical flower-clusters. 
pekinensis flowers next; this is also shrubby in habit, sometimes 
twenty feet tall and broad, with stout spreading stems covered with 
yellow-brown bark separating readily into thin flakes like that of some 
of the Birch- trees, dark green narrow pointed leaves, and short unsym- 
metrical flower-clusters usually in pairs at the ends of the branches. 
This species holds its leaves later in the autumn than the others and 
produces great clusters of flowers every year; the other species usually 
flower abundantly only every other year. The last of the Tree Lilacs 
to flower, S. japonica, is a native of northern J apan. and is generally 
a tree sometimes forty feet high, with a tall straight trunk covered 
with lustrous brown bark, like the bark of a Cherry-tree, a round- 
topped head of upright branches, broad, thick, dark green leaves, and 
erect mostly symmetrical flower-clusters from twelve to eighteen 
inches in length. It is one of the handsomest of the small trees which 
bloom here at the end of June or early in July, and appears to be more 
common in cultivation now than the other species of this group. These 
three plants can be seen growing on the bank in the rear of the path 
which leads through the Syringa Collection. 
