12 



SILVA OF NOB Til AMERICA. 



CUPULIFERiE. 



sively. The orange and yellow colored caterpillars of Anisota no scars being left on the acorns, and in the autumn the larvae 



pelludda 



emerge. 



Ilubner, often denude whole trees, the first two being northern ^^ The number of parasitic fungi known to affect Oak-trees in 



the United States exceeds that accredited to the trees of any other 



and the last southern in range. The prickly stinging caterpillars 



of Hemileuca Maia, Drury, as well as various species of Datana American genus, several hundred species being recorded, chieriy 



and of Orgyia, or Tussock Moths, commonly feed on Oaks over a as infesting Quercns alba, Qiiercus velutina, Qiiercus coccinea, and 



large portion of the continent. Qiiercus rubra. It is not probable, however, that these species are 



LocJimceus maiiteo, Doubleday, has been reported as quite inju- more liable to the attacks of fungal diseases than other American 



rious in several localities. The larvse of a number of species of Oak-trees, and the great number known to afflict them can prob- 



Bombycidse, including several silk-worm moths, like Telea Poly- ably be accounted for by the fact that they are exceedingly abun- 



phemusy HUbner, are common on Oaks. Noctuidse are also abun- dant in those parts of the country where fungi have been most 



dant upon them, and of tliis group many species of the genus carefidly studied. Nearly fifty species of fungi are parasitic on. 



Quercus agrifolia, and many species are found on Quercus Marilan- 

 dica and Quercus Virginiana. Only a single fungal parasite is 

 known thus far on Quercus Californica and Quercus Wisltzeni, but 



Catocala make them their food-plant, being, however, rarely very 

 troublesome. 



Various Leaf-rollers are common on Oak-trees, among them 

 being Toririx quercifoliana^ Fitch, and other allied species, and the fungal diseases of California Oaks have not as yet been care- 



d. 



Notwithstanding the large number of parasites on North Amer- 



peculiar to itself. Cryptolechia quercicella, Clemens, and Crypto- ican Oaks which are known to systematic botanists, scarcely any- 

 lechia Schlagenella, Zeller, live between the surfaces of leaves thing has been done in studying the special diseases which they 

 which they draw and fasten together by silken threads. 



species of Caccecia, Cenopis, Gelechia, and other genera, each roll- fully exi 

 ing or folding the leaves or parts of the leaves in the manner 



cause. 



Whe 



Forty or fifty species of Leaf-miners belonging to the family of European scientific foresters, it will, no doubt, be found that 



Tineidse, and principally to the genera LithocoUetis, Tischeria, many of the fungi now recognized produce serious diseases in our 



and Nepticula, have been described as harbored by American Oaks. Many of the species of Polyporus and its allies, which are 



Oaks. Their small larvse cause blotches or slender mines or tun- known to cause rotting of Oak wood in Europe, are common in the 



nels of various forms, and mostly live within and feed upon the United States, and probably do the same damage here. Dcedalea 



parenchyma of the leaves, the epidermal surfaces being left intact quercinOy Persoon, appears to be less common here than in Europe, 



except at the points of ingress or egress. Larvse of Selandria although it is found not infrequently. But one fungal disease of 



Quercus-alba, Norton, and other Saw-flies, sometimes injure the Quercus has attracted much attention in the United States, and 



leaves of Oak-trees ; various species of aphids are common upon this only in recent years. It is n leaf disease caused by Gloeo- 



them, and Red Mites, Tetranychus telariusy Linuseus, in dry seasons sporium CanadensCy Ellis & Everhart, which most frequently attacks 



sometimes cause them to turn gray. 



Quercus alba, although it is probably not distinct from a similar 



Many forms of galls on leaves and twigs, and also on flowers, disease of Quercus coccinea, Quercus rubra, and other species. It 



fruits, and roots, are well known where Oaks abound. Some are appears in late spring and early summer as soon as the leaves 



characteristic of and peculiar to certain single species of the genus, have grown to their full size, and is characterized by the presence 



while others occur on several allied species. These galls are of brown patches near their tips and margins. These dead por- 



mostly produced by insects of the Hymenopterous family, Cyni- tions gradually increase in size, and the diseased leaves curl and 



pidse, about one hundred and fifty species of which have been shrivel. When the attack is serious, a large part of the foliage 



described as occurring on the various Oaks of North America, of the tree is affected ; but, as a rule, only certain leaves are 



although a few are recorded as the work of the Dipterous family, attacked, and when they at last fall off there is at least an attempt 



Cecidomyidse, and of Mites. The large round Oak-apple, Amphi- on the part of the tree to produce a new crop in their place. 



bolips spongifica, Osten-Sacken, common on Quercus velutina, is one 



fungus as seen externally consists of small dots, hardly 



of the most conspicuous of Cynipidous galls. Many American Oak- visible to the naked eye, which are scattered irregularly over the 



galls are rich in tannic and gallic acids, but have rarely been used surface of the leaves, and scarcely differ in color from the parts 



as a substitute for the officinal Oak-galls of southeastern Europe already dead. The disease has attracted attention principally in 



and Asia Minor. The full life-histories of most of our species of the northern and eastern states, where Oaks are grown for shade 



gall-making Cynipidse are still unknown, and it is probable that and ornament, and where the injured foliage is, therefore espe- 



future studies of them will reduce the list of so-called species, as cially noticeable. It occurs, however, even more frequently on 



it has been shown that the alternating generations of some species trees growing in the forest. 



different 



young 



have even been regarded as members of distinct genera, (See trees, and especially to Quercus rubra, although by no means 



* • 



Adler, Zeit, filr Wissen. ZooL xxxv. 151, t, 10-12 \_Uber den Gene- limited to this species, is caused b 



rationswechsel der Eichen-Gallwespen'].) It attacks the smaller branches, bre 



' Nummularia 

 .king throup-h 



In all parts of the country the fruit of different species of in elongated cone-like black patches several inches or even one or 



Quercus is often seriously infested by weevils of various species of two feet in length, but usually not more than two inches in 



the genus Balaninus. Balaninus nasicvs, Say, seems to prefer the breadth. Its development is slow, the patches, which hardly rise 



species with annual maturation, while Balaninus Quercus, Horn, above the general surface of the bark, remaining on it for months, 



has only been observed on biennial-fruited species, which Balani- and then finally crumbling away, leaving the smaller branches 



nus uniformis, Leconte, also appears to prefer. (See J. Hamil- quite dead and marking the larger ones with unsightly wounds, 



ton, Canadian Entomologist, xxii. 1.) The work of these weevils This parasite belongs to the Pyrenomycetes, an order including a> 



often destroys a large part of the fruit of Oak-trees, that of large number of fungi which grow on Oaks, some of them, like Num- 



Quercus rubra being particularly liable to their attacks. Their wiwtor«a;?wnc^wZa^a, Saccardo, and ^n^Ao5foma airojownc^a^a, Saccardo, 



eggs are deposited by the beetles in the ovaries of the flowers, producing diseases similar to that caused by Nummularia Clypeus. 



