200 



The Dictionary of Gardening, 



Popnliis — continued. 

 pale, with rows of black, bristly warts. The larvse, 

 when touched, emit an ill-smelling', milky fluid. The 

 pupSD are suspended from the leaves by the tail, and are 

 coloured like the larva>. The larvae feed in groups on tlie 

 leaves, gnawing" them into holes, so that only the network 

 of veins is left. L. Tromuhc is a nearly allied species 

 common in some localities. It ag^rees with L. Populi, 

 except in being slightly smaller and greenish-blue, with 

 the wing-cases coarsely pitted, more yellowish-red, and 

 not tipped with black ; and the antenna? are tipped with 

 brown. Another nearly allied insect, of similar habit, 

 is Phrafora viiellhioe. The same remedies may be em- 

 ployed against all the three species. See Fh,ratora. 



Numerous species of Sawflies (chiefly of the genus 

 Nemafus) feed, as larvae, on Poplars, and most of these 

 feed on Willows also; but none of them have been 

 observed to do damage enough to require special 

 measures to be taken against them. The same may be 

 said of those Lepidoptera that feed, as larvte, on the 

 leaves of Poplars. If any remedy is required, hand- 

 picking, or mere shaking them off the branches, is 

 usually sufficient. Further information in regard to 

 several of them is given under the following heads : 

 Lackey Moth, Liparis, Fuss Moth, Sphingidse 

 (Poplar Hawk Moth), and Tussock Moths ; though, under 

 several of these heads, Poplars are not specially men- 

 tioned in connection with the insects, which, in these 

 instances, feed on many kinds of plants. In addition 

 to these, a very large number of moths live on Poplars, 

 but do not call for mention individually. 



Poplars, including among them the Aspen, bear galls 

 of various forms. Among the commonest of these are 

 the hard, pea-like swellings on the leaf-stalks, formed 

 by a midge [hiplosis Treiunlce) ; the rather conical, hollow 

 galls on leaf- stalks, tenanted by Aphides {Pcmpltigutt 

 hursarius) ; the curious, spirally-twisted leaf-stalk galls 

 of another kind of Aphides {Pemphigus spiroflieccF) ; and 

 the mite galls of Aspens, which vary in size from the 

 galls of Heliaczeus Populi (about the size of pin-heads, 

 at the base of the leaf -blade) to those of Ba tone u s 

 Populi, which form masses, up to 3in. in diameter, on 

 the young twigs or the trunk — fleshy, and green or red 

 when fresh, but becoming hard, dry. and friable. These 

 mite-galls are, in reality, the work of mites of the 

 genus Phyiopfus (see Mites), though the galls have 

 received special names. Galls of all kinds do compara- 

 tively little harm to the trees, except rendering them 

 unsightly. They should be cut off and destroyed, if it 

 is desired to free the trees from them 



P. alba (white).* Abele; White Poplar. _^., catkins 2in. to 4in. 

 long, females shorter. IVI;irch and April. I. on the bnmches lin. 

 to 3in. long, broadly ovate-cordate, sinuate-lobed, glahrous in age ; 

 petioles very short, slender, compressed ; leaves on the suckers, 

 which are numerous, deltoid -ovate, lobed and toothed, 2in. to 4in. 

 in diameter. Branches spreading; buds cottony, h. 60ft. to 

 100ft. Northern hemisphere (Britain). The wood of this tree 

 is white in colour, light, and useful, but does not burn easily. 

 (Sy. En. B. 1299.) 



P. a. Bolleana (Bolle's).* A remarkable form, of columnar or 



pyramidal hal>it, the countei-part (under P. alba) of the Lombardy 



Poplar. (G. C. ii. s., xviii. 557.) 

 P. a. canescens (hoary). Grey Poplar. I. of the branches hoary 



beneath or glabrous ; those of the suckers, angled and toothed. 



The wood of this variety is said to he superior to that of the type. 



See Fig. 253. (Sy. En. B. 1300.) 

 P. angulata(an;4:iilar). A synonym of P. vwnilt/era. 



P. balsamifera (balsam-bearing).* Balm of Oilead ; Balsam 

 Poplar ; Tacamahac. I. ovate, gradually tapeiing, and pointed, 

 finely serrate, smooth on both sides, whitish, and reticulately 

 veined beneath. Branches round ; buds large, copiously varnished 

 with fragrant resin, b. 70ft. North America. 1692. 



P. b. candicans (whitish). ;. broader, and more or less heart- 

 shaped, pointed, serrate ; petioles usually hairy. Syn. P. macro- 

 pinjlhi. 



P. b, laurifolla (I^mrel- leaved). I. oval, oblong, and long- 

 acuminate or lanceolate, sometimes sub-cordate, toothed ; 

 younger; ones (and branches) slightly pilose. Siberia. Syn. 

 P. lauri/olia. 



Populns — continued . 



P. b. suaveolens (sweet-siuelling). I. broadly elliptic, acuminate, 



obtuse, toctthed, slightly pubescent on the nerves and petioles. 

 Rocky Muuntains. 



P. b. Viminalis (twiggy), l. long-lanceolate. Bninches angular, 



elongated, sli-nder. 



P. canadensis (Canadian). A synonym of J', monilifera. 



P. c. aurea (gdlden). A synonjnn of p. monilifera aurea. 



P, dilatata (dilateil). A synonym of /'. iiitjm jn/rann\ialig. 



P. fastigiata (pyramidal). A synmiym of /*. ni;fra pyramidalis. 



P. grseca ((.ivcian). A synonym of P. treutitloides. 



P. grandidentata (large-toothed), yf., male catkins 3in. to 4in. 

 bmg : females l;,in. to 2in. long. March. /. roundish-ovate, 

 with large and irregular, sinuate teeth, when young Sin. to 5in. 

 long, densely covered with white silky wool, at length smooth on 

 both sides, lin. to 3in. long. Branches and branchlets cylin- 

 drical ; buds pubescent, sometimes slightlv glabrous, h. 60ft 

 North America, 1772. (E. T. S. M. ed. ii. 278.) Of this species 

 there is a weeping variety (iiemhda) in cultivation. 



Fig 255. 



Portion of Branch am> Male Catkin of Populus 



alba canescens. 



P. heterophylla (variable-leaved). Jl., male catkins thick, Sin. 

 to 4in. long, dense ; females 2in. long, loose. March. I. 6in. to 

 12in. long, 4in. to Sin. broad, cordate or roundish-ovate, obtuse, 

 serrate, white-woolly when young, at length nearly smooth, except 

 on the elevated veins beneath. Branches round, pale ; buds 

 highly pubescent, thick, short, obtuse, h, 40ft. to oDft. North 

 America, 1765. 



P. lanrlfoUa (Laurel-leaved). A synonym of P. balsamifera 

 laurifi'Ua. 



P. macrophylla (large-leaved), of Lindley. A synonj-m of P. 

 baUami/tra candii'ana. 



P. monilifera (beaded).* Necklace Poplar, t. on young plants 

 and suckers, heart-shaped, 7in. to 8in. long and wide ; those on 

 full-grown trees, only one-fourth that size, ami commonly with- 

 out the sinus ; all crenate-serrate, or with obtuse, cartilaginous 

 teeth. Branches acutely angular or winged. A. 80ft. or more. 

 North America, 1758. Syns. /'. an;ndata, P. canottciiA'is. 



P. m. aurea (golden). A very useful, ornamental tree, only 

 differing from the type in the decided golden-yellow tint of the 

 leaves. "Syn. P. canadeitgi-s aurea. 



P. nigra (black).* Black Poplar. Jl., male catkins 2in. to Sin. long, 

 cylindrical ; females shorter, ascending, the peduncle curved in 

 front. April, l. lin. to 4in. long, rhombic, deltoid, or sub- 

 orbicular, finely crenate-seiTate, the angles rounded, acuminate ; 

 young ones silky beneath and ciliate ; petioles slender, com- 

 pressed. Branches gTeenish-white ; branchlets pubescent when 

 young, and, as well as the highly viscous buds, yellowish, ft. 50ft. 

 to 60ft. Europe, North Asia. The Black Poplar is of rapid 

 gi'owth and short duration ; the wood is light, and is much used 



