43 
in the Arboretum several years ago and is supposed to be a hybrid be¬ 
tween two American species, P. inodorus and P. pubescens. It is a 
large and shapely shrub with pure white, only slightly fragrant flowers 
an inch and three-quarters in diameter and borne in erect clusters. 
This hybrid is a free-flowering plant and when the flowers are open it 
is the showiest plant in the Syringa Group. 
These early hybrids are the result of natural cross fertilization, and 
the systematic breeding in the genus dates from the time when Lemoine 
first crossed the Rocky Mountain P. microphyllus with P. coronarius 
and produced a plant to which he gave the name of P. Lemoinei. 
Lemoine then crossed his P. Lemoinei with P. insignis and produced a 
race to which the general name of P. polyanthus has now been given. 
Well known forms of this plant are “Gerbe de Neige’’ and “Parvillon 
Blanc.” To another race of the Lemoine hybrids the name of Phila- 
delphus cymosus has been given. This race was obtained by crossing 
P. Lemoinei and P. pubescens or some related species. “Conquete” 
is considered the type of this group. Other well known plants which 
are thought to belong here are “Mer de Glace,” “Norma,” “Nuee 
Blanche,” “Rosace,” “Voie Lactee,” and “Perle Blanche.” Another 
race of hybrids with double racemose flowers raised by Lemoine and of 
doubtful origin is called P virginalis. The type of this group is Le- 
moine’s “Virginal.” Other plants referred to it are “Argentia,” 
“Glacier,” and “Bouquet Blanc.” 
Tree Lilacs. As the flowers of the late-flowering group of the true 
Lilacs fade the earliest flowers of the so-called Tree Lilacs begin to 
open. There are three of these Lilacs which all bear large clusters of 
white or yellowish white flowers with a corolla shorter than the sta¬ 
mens, while in other Lilacs the corolla is longer than the stamens which 
are hidden in its throat. The flowers of the Tree Lilacs are white and 
all have the disagreeable odor of the flowers of the Privet; the leaves 
fall in the autumn without change of color. The first of these plants 
to flower, Syringa amurensis, a native of eastern Siberia as its name 
implies, is a shrub in habit, twelve or fifteen feet high with dark close 
bark, broad thick leaves dark green above and pale below, and short, 
broad unsymmetrical flower-clusters. S. pekinensis from northern 
China flowers next. This is also shrubby in habit, sometimes twenty 
or thirty feet tall and broad, with stout, spreading stems covered with 
yellow-brown bark separating readily into thin plates like some of the 
Birch-trees, dark green, narrow, pointed leaves and short and 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 quantities of flowers every year, the other species usu¬ 
ally flowering abundantly only every other year. The last of the Tree 
Lilacs to flower, S. japonica, is a native of northern Japan, and is 
really a tree sometimes forty feet high with a tall straight trunk cov¬ 
ered 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 
long. This is one of the handsomest of the small trees which bloom 
here at the end of June or early in July. The first flowers of S. jap¬ 
onica are now opening; they promise to be in good condition until after 
