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somest Crabapple now cultivated. Malus rubrifolia is the name which 
will be given to the hybrid Crabapple recently mentioned in Bulletin 
No. 5 of this volume. It finds a place in the list of Arboretum hybrids 
because it is now known that it was either raised from seeds gathered 
in the Arboretum or that it was a seedling pulled up from the neigh- 
borhood of the Arboretum plants of Malus Niedzwetzkyana. These Ar- 
boretum hybrids show that new plants may appear spontaneously in 
any large collection of cultivated plants, that such spontaneous hybrids 
are sometimes valuable and that others, although interesting, can add 
little or nothing to the beauty of gardens. They show, too, that if the 
fertilization of the flowers of one plant by the pollen from the flowers 
of a different species or hybrid can produce such results as Sorbus ar- 
noldiana and Malus arr.oldiana, systematic and intelligently directed 
hybridization might with the abundant material here produce plants 
more beautiful than any now known in our gardens. 
Rhododendrons. The severe winter has not killed any of the plants 
in the Arboretum collection, but many Rhododendron branches have 
been broken by the weight of snow and ice, and the flower-buds of a 
few of the hybrids have been injured. The southern Appalachian R. 
carolinianum was the first species to open its buds this year and for 
the last ten days the plants have been covered with their small, rose- 
colored flowers. Almost as early were some of the forms or hybrids 
of R. caucasicum. The most satisfactory of these for general cultiva- 
tion in this climate is probably “Boule de Neige, ” which is a dwarf 
round-headed plant with good foliage and dark green leaves. It is per- 
fectly hardy and rarely fails to flower. “Mont Blanc’' is another of 
these plants which can be depended on to give satisfaction. As it grows 
in the Arboretum it is a dwarfer plant than “Boule de Neige,” but the 
clusters of flowers and the flowers are larger; the flowers when the buds 
first open are rose color but soon become white. There are other named 
hybrids of R. caucasicum in the collection, but there is still much for 
us in this country to learn about the origin, correct names and hardi- 
ness of this race of Rhododendrons. The flower-buds of the Caucasian 
R. Smirnowii were uninjured by the winter and the plants are covered 
with the handsome pink flowers which make this one of the desirable 
Rhododendrons for Massachusetts gardens. Hybrids of this plant raised 
in England which are hardy in the Arboretum have lost their flower- 
buds, but those of a hybrid of the Japanese R. Metternichii, a species 
which grows badly here, with one of the hybrids of R. catawbiense, also 
raised in England a few years ago, are uninjured. The flower-buds of 
the two dwarf hybrids, R. myrtifoliurn and R. arbutifolium, useful 
plants to border beds of larger growing broad-leaved evergreen shrubs, 
are covered with uninjured flower-buds. The Rhododendrons most com- 
monly found in American gardens are hybrids of R. catawbiense of the 
southern United States, and the first of them to flower here, R. cataw- 
biense album has been in bloom for several days. One of this race 
called “Bismarck,” which came to the Arboretum from Dresden, also 
flowers early and is unusually handsome this year. The largest number 
of Rhododendrons will probably be in bloom on Saturday and Sunday, 
the 12th and 13th of June. The collection is at the base of Hemlock 
Hill close to the entrance to the Arboretum from South Street. This 
entrance is most easily reached from Forest Hills by following South 
Street past the Bussey Institution. 
