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clusters are developed on one of the short lateral branchlets, and as 
the flowers in the upper clusters on the branchlet do not open until 
later than those of the lower clusters the plants are covered with fresh 
flowers for a long time. This Robinia will probably prove to be a 
better garden plant than the Rose Acacia, for although the flowers 
are not as large or of as deep rose-color it does not spread by under- 
ground stems, a habit which makes the Rose Acacia a weed which once 
established it is almost impossible to control. 
The Pawpaw (Asimina triloba). A colony of this handsome tree, 
which is very common in the southern states but at the north occurs 
in only a few isolated stations, is now established on Hickory Path 
near Centre Street, and this yeat the leafless branches have been 
well covered with the curious, dark-brown, bad-smelling flowers. Under 
favorable conditions the Pawpaw is sometimes a tree forty feet high 
with a tall stout trunk; it has handsome drooping, dark green leaves 
often a foot long and six inches wide, but it is chiefly interesting as 
the only extra-tropical North American tree, with the exception of 
some of the wild Plums, which produces edible fruit. This is borne 
in few-fruited clusters and is from three to five inches long and from 
an inch to an inch and a half in diameter, greenish yellow, becoming 
almost black when fully ripe with semitranslucent, sweet, luscious 
flesh. The ripe fruit does not bear transportation and is rarely sold 
in markets, and so is little known except to boys who live near Pawpaw 
thickets. The American Genetic Association, however, has now taken 
up the possibility of the improvement of this fruit and is offering 
prizes for information about the largest trees, and about trees, regard- 
less of their size, which bear fruit of unusually good quality. 
Rhododendron (Azalea) calendulaceum. Of the American Azaleas the 
pink-flowered R. Vaseyi and the Rhodora are already past blooming. 
The flowers of two other pink-flowered species, R. canescens and R. 
nudiflorum, are fast falling, but R. calendulaceum from the Appala- 
chian Mountain slopes, the handsomest of the whole group, is now be- 
ginning to open its yellow or orange-colored flowers. This is a per- 
fectly hardy shrub which can be found scattered through the roadside 
plantations in the Arboretum and in a large mass on the slope below 
Azalea Path where the variation in the color of the flowers can be 
studied. As a garden plant this is superior to any of the hybrids 
which have been in part derived from it. A large number of these 
hybrids were raised in Europe nearly a century ago by crossing R. 
calendulaceum with the American R. viscosum and the Caucasian R. 
luteum. These plants are usually known as Ghent Azaleas, but the 
correct name for them is Rhododendron (Azalea) Mortierii, for the 
Ghent baker named Mortier who raised a number of such hybrids. As 
found in nurseries these plants are all grafted and therefore do not 
grow so well as seedlings. The hardiness of many of them is reduced 
by the blood of the Caucasian species which is not hardy in this cli- 
mate, and they are more or less valuable here as garden plants as the 
influence of the blood of the American species is greater or less. None 
of them surpass, however, R. calendulaceum in the beauty of their 
flowers and none of them are so long-lived or so satisfactory garden 
plants. 
