SALICACEZ. 101 
SILVA OF NORTH AMERICA. 
the leaves and young growing shoots; and the genus is subject to serious fungal diseases, although 
these are not so numerous as those found in some other large genera.’ 
The species of Salix can be readily raised from seeds and from cuttings of large or small branches 
inserted in the open ground in the spring. The hardiness of most of the Willows, the ease with which 
they can be cultivated, and the beauty of their flowers and foliage, make many of the species desirable 
ornamental plants. Several of the arborescent forms grow rapidly into shapely trees, although they are 
often disfigured by the breaking of the branches, which are easily separated at the joints by high 
winds. 
Salix, the classical name of the Willow, was adopted by Tournefort? and other pre-Linnzan 
botanists as the name of the genus. 
on Willows, although rarely troublesome. A few species of Sphin- 
gid live upon the Willows. Bombycide are much more abun- 
dant, and larve of most of the large American silk-worms will feed 
upon the leaves, while Tussock Moths and Fall Web-worms fre- 
quently do them much damage. Deilinia variolaria, Guenée, and 
other span-worms occur upon Willows in varying numbers in dif- 
erent localities and seasons. 
Species of Lithocolletis, Gelechia, Nepticula, Aspidisca, and other 
Tineids mine the leaves, their larve living within tortuous or blotch 
mines between the epidermal layers. Larve of Crepidodera Helz- 
ines, Linneus, Lina scripta, Fabricius, Lina Lapponica, Linneus, 
Galeruca decora, Say, and other Chrysomelide are sometimes very 
abundant and are frequently the most destructive of the foliage- 
eating beetles. 
Saw-fly larvae of numerous species prey upon American Willows. 
The large Cimbex Americana, Leach, has been found to damage 
seriously the young shoots by gnawing and girdling them, while the 
larve feed upon the foliage. Larve of Nematus ventralis, Say, are 
sometimes quite troublesome, several broods being produced during 
the season ; and the larve of other species of Nematus, of Selan- 
dria, Dolerus, and other Tenthredinide, are frequently destructive 
to the foliage. Phyllecus integer, Norton, has been found to girdle 
and destroy the tips and young shoots, in which the larve live as 
borers. 
The leaves and twigs of the various species are subject to distor- 
tions and gall growths caused by many species of hymenopterous 
and dipterous insects. Among the former, various species of Euura 
and Nematus produce diversely shaped and often thick-walled galls 
which are borne on the leaves or twigs. But the most generally 
conspicuous and peculiar galls on Salix in North America are 
formed by the action of various species of Gall-gnats or Cecido- 
myidz belonging to the order of Diptera. These galls are usually 
borne on young twigs and sometimes on the leaves, and are of a 
woody or a leafy character according to the species. Cecidomyia 
Salicis-siliqua, Walsh, produces a smooth oblong woody gall which 
occurs near the tips of the twigs of several species of Willow. 
Other galls of similar character but of various forms peculiar to 
certain Willows are recorded as distinct species. Cecidomyia Sali- 
cis-triticoides, Walsh, arrests the growth of the branchlets of Salix 
cordata and other species, causing the leaves to become more or less 
crowded, the affected part of the twig appearing after the leaves 
fall as a long swelling roughened by the prominent leaf-scars. 
The most interesting and curious galls affecting the Willows are 
those which assume a cone-like shape at the tips of the branches of 
Ceci- 
domyia Salicis-strobiliscus, Walsh, may be taken as an example ; it 
Salix discolor, Salix humilis, Salix cordata, and other species. 
is an ovate cone-like gall usually about an inch and a half long and 
three fourths of an inch or more in diameter in its widest part. It 
is formed of many overlapping scales which are suppressed, modi- 
fied, and crowded leaves, and the solitary larva lives and pupates 
in its centre. Minute galls of curious forms are also produced upon 
the leaves by species of Phytoptus or mites. 
Willows are often infested by several species of aphids of such 
genera as Lachnus, Chaitophorus, and Rhopalosiphon ; and scale 
insects, chiefly of the genera Chionaspis and Aspidiotus, sometimes 
injure them. 
1 The leaves of most species of Salix are infested by a common 
mildew, Uncinula Salicis, Winter, which covers them late in the 
season with a thick white web, and are also liable to be attacked 
by fungi of the genus Melampsora. Several species of this genus 
have been noticed in North America, but their distinctive charac- 
ters are not well understood, and, as is the case with the Melam- 
psore which attack the species of Populus, writers do not agree in 
Rhy- 
tisma salicinum, Fries, a common and conspicuous fungus which 
regard to the plants on which the ecidial conditions exist. 
forms slightly raised black patches often of considerable size on 
the leaves of Salix, is found on many of the American species. 
This fungus is abundant in all parts of the country from the sea- 
coast to alpine regions. In spring and early summer the small 
branches of Salix discolor are so densely covered with small pow- 
dery black spots that the hands of a person breaking off a branch 
are often blackened. This fungus, which belongs to the group of 
Fungi Imperfecti, has received several names in America, the latest 
being Trimmatostroma Americanum, Thiimen, although it is probably 
not different from Trimmatostroma Salicis, Corda, of Europe. Of 
the larger fungi belonging to the Polyporei, or Punk-fungi, Tra- 
metes suaveolens, Fries, recognized by its color, which is at first white 
and later yellow, and by its anise-like odor, and Polyporus salicinus, 
Fries, are found on Willows in the United States. Among the other 
hymenomycetous fungi that attack Salix in North America are 
Agaricus salignus, Schrader, the characteristic Corticium Oakesii, 
Berkeley & Curtis, and the pretty blood-colored Corticium cruentum, 
Schrader, found on fallen branches in moist places. 
2 Inst. 590, t. 364. 
