42 



SILYA OF NORTH AMERICA. 



ULMACE^ 



disfigure the foliage and destroy the ornamental value of Elm-trees ; and is subject to numerous fungal 

 diseases.^ 



Elm-trees can be easily raised from seeds^ which germinate as soon as they are ripe ; they can be 

 multipHed by shoots which in some species are produced in great numbers from the roots, and the 

 seminal varieties can be propagated by grafting. 



Ulmus, the classical name of the Elm-tree, was adopted by Tournefort/ and afterward 

 Linnaeus, as the name of the genus. 



widely 



It ob- 



Massaria Ulmiy Fuckel, which is also European and is usually 



tains its food chiefly through the bark of the trees, which often confined to foreign species, is occasionally found on the American 



acquires a black appearance from the excretions or honey dew of Elms ; it attacks the twigs and younger branches, where it appears 



the insects (L. O. Howard, Insect Life, ii. 1889, 34. — J. G. Jack, in the form of small scattered black papillae which soon break up 



Garden and Forest, ii. 461, f. 129 ; iv. 184). Other plant lice and when the bark becomes of a sooty black color. This disease ap- 



scale insects affect the Elm sometimes injuriously. A mite, Phy- pears to be perennial and extends from branch to branch, disfigur- 



toptus Ulmij Garman, produces minute club-shaped galls on the ing and often killing the trees. 



leaves, and the fruit is sometim 

 ing to the Curculio family. 



Ulmus is infested by certain characteristic leaf mildews, f/n- 

 cinula macrospora, Peck, is found on Ulmus Americana, Ulmus alata, 



^ The most serious fungal disease of Ulmus in North America is and Ulmus fulva ; and Uncinula intermedia^ Berkeley & Curtis, also 



caused by Phleospora Ulmiy Wallri, which is sometimes very abun- occurs on the leaves of Ulmus alata. Among edible fungi, Agaricus 



dant in the eastern states, especially on foreign species, although it ulmarius, BuUiard, one of the lateral edible fungi, is not uncommon 



also occurs on Ulmus Americana. The disease, which was proba- on the large branches of Elms in thickly settled districts. Panics 



bly imported from Europe many years ago, covers the leaves in dealbatus, Berkeley, is sometimes found on Elm-trees, and the 



the late summer with many small spots, from which exude in damp characteristic Polyporus conchifery Schweinitz, abounds on the older 



weather rose-colored gelatinous masses. The diseased leaves fall limbs of Ulmus Americana, appearing in the form of small disks or 



prematurely, and the fungus continues to develop after they have flat cups which are usually more or less confluent with concentric 



reached the ground, appearing in its mature state only at the end zones of the white and dark gray colors characteristic of this spe- 



of winter. This disease, which is sporadic in its habit and occurs cies. 



only in limited areas, sometimes does considerable damage. 



2 Inst. 601, t. 372. 



CONSPECTUS OF THE NORTH AMERICAN SPECIES. 



Flowers vernal, appearing before the leaves. 



Flowers on slender drooping j^edicels ; fruit ciliate on the margins. 



Bud-scales glabrous ; branchlets destitute of corky wings ; fruit glabrous ; leaves obovate- 



oblong to oval, usually smooth on the upper, soft-pubescent on the lower surface .... 1. U. Amekicana 

 Bud-scales puberulous ; branches often furnished with corky wings ; fruit hirsute ; leaves 



obovate to oblong-oval, smooth on the upper, soft-pubescent on the lower surface .... 2. U. RACEMOSA. 

 Bud-scales glabrous or slightly puberulous ; branchlets furnished with broad corky wings ; 

 fruit hirsute ; leaves ovate-oblong to oblong-lanceolate, smooth on the upper, soft-pubescent 



on the lower surface - . . <> 3. U. ALATA. 



Flowers on short pedicels ; fruit naked on the margins. 



Bud-scales coated with rusty hairs ; branchlets destitute of corky wings ; fruit pubescent ; 



leaves ovate-oblong, scabrous on the upper, pubescent on the lower surface 4. U. fulva. 



Flowers autumnal, appearing in the axils of leaves of the year on short pedicels. 



Bud-scales puberulous ; branchlets furnished with corky Avings ; fruit hirsute ; leaves ovate, 



scabrous on the upper, soft-pubescent on the lower surface 5. U. CRASSIFOLIA. 



