CORNACEE, SILVA OF NORTH AMERICA. 65 
The wood of Cornus is hard, close-grained, and durable, and is used in turnery and for charcoal. 
The greatest value of Cornus, however, is for the decoration of parks and gardens ; several of the 
species produce flowers and fruits of remarkable beauty, and others cover their branches with brilliantly 
colored bark. 
The plants of this genus are little injured in America by the attacks of insects! or by fungal 
diseases.” 
The generic name, from cornu, relates to the hardness of the wood produced by the different’ 
species. 
nic,” and was chiefly prized by the Indians for smoking, although 
in those parts of the country where it was not found they used for 
the same purpose the bark and leaves of several other plants. (See 
Parry, Owen Rep. Geolog. Surv. Wisconsin, lowa, and Minnesota, 
613.) 
1 The Fall Web-worm sometimes disfigures Cornus florida, and 
the larve of Antispila cornifoliella, Clemens (Proc. Phil. Acad. 1860, 
11), mine within its leaves, and Coleophora cornella, Walsingham 
(Trans. Ent. Soc. Lond. 1882, 432), feeds on the leaves of Cornus 
pubescens in California. The larve of « Saw-fly, Harpiphorus vari- 
anus, Norton, destroy the foliage of several of the shrubby species 
of Cornus in many parts of the country (J. G. Jack, Garden and 
Forest, ii. 520). One or two species of unidentified borers injure 
the wood of Cornus, and a whitish Scale-insect is often abundant 
on the bark of plants of some species. 
2 The American arborescent species of Cornus are attacked by 
a number of characteristic fungi; Myzosporium nitidum, Berke- 
ley & Curtis, which is common on Cornus alternifolia, kills the 
young twigs and branches, which become yellowish brown and often 
highly polished and spotted with the minute perithecia of this 
parasite. Septoria cornicola, Desmaziére, produces numerous small 
white spots powdered with purple on the leaves of Cornus florida 
and Cornus alternifolia and on those of many shrubby species. Of 
all the American species, Cornus florida appears to be the most 
subject to attacks of fungi, about thirty species having been de- 
tected on this tree. Among mildews, Microsphera Alni, Winter, 
is common on the leaves of Cornus alternifolia and Cornus stolo- 
nifera. Phyllactinia guttata, Léveillé, a common fungus on the 
Chestnut-tree, occurs also on Cornus florida and Cornus stolonifera. 
A sooty black fungus, Dimerosporium pulchrum, Saccardo, is not 
rare on the leaves of Cornus paniculata and Cornus sericea, but 
although it disfigures them it does not penetrate into the interior 
of the plants. 
SYNOPSIS OF THE NORTH AMERICAN ARBORESCENT SPECIES. 
Flowers in a dense cymose head surrounded by a conspicuous involucre of 4 to 6 petal-like 
scales from buds formed the previous summer. 
Heads of flower-buds inclosed by the involucre during the winter; involucral scales 4, obcor- 
date or notched at the apex ; leaves ovate or elliptical . 
Heads of flower-buds not inclosed by the involucre; involucral scales 4 to 6, oblong to obovate, 
usually acute at the apex ; leaves ovate or rarely obovate .s 
Flowers in a cymose head without involucral scales, terminal on shoots of the year. 
Leaves mostly alternate and clustered at the ends of the branches . 
1. C. FLORIDA. 
2. C. NuTTALLII. 
3. C. ALTERNIFOLIA. 
