1638 ARBORETUIVI AND I lUJTlCETUM. F'ART III. 



from w liich it will be impossible entirely to extricate them, till both the male 

 and female plants of each sort have been cultivated together for a number of 

 years in the same garden. Judging from the plants in the London nurseries, 

 auti in the arboretums of the Horticultural Society and Messrs. Loddiges, we 

 think that all the kinds now in actual cultivation in Britain may be included 

 under the heails of P. lilba, P. trcmula, P. nigra, and P. balsamlfcra. 



Poplars, from their rapid growth and great bulk, are liable to have their 

 branches broken off by the wind ; in which case, if care is not taken to protect 

 the wounil from the weather, the water enters, and the trunk soon rots and be- 

 comes the preyjof insects, which in their turn are fed on by birds. The larvae of 

 a number of moths live on the leaves of the poplars, such as Tortrix populana, 

 ^ombyx populi, Cerura viiuda, Smerinthus populi, S. ocellatus, (the eyed 

 hawk moth), Anactimpsis popultlla, and a number of others, some of which 

 will be noticed under |)articular species. The larvae of Cossus Ligniperda 

 (see p. 1386.), of yEgeria crabroniformis (see Mag. Nat. Hist., iv. 445.), and 

 of some others, live on the wood. The larva of the puss moth (Ceriira vinula) 

 is one of the few caterpillars that are known to have the voluntary power of 

 communicating electricity. An interesting account of the manner in which 

 this was discovered by a naturalist in Selkirkshire, is given in the JMagazine of 

 Natural Histon/, vol. iv. p. 281. The larva of this insect is very common on 

 poplars and willows in Switzerland, where the pupa often remains two full 

 years, before it assumes the perfect state. (//•«/., viii. jj8.) Populus grae'ca 

 affords food to this moth, to the po[)lar hawk moth (Smerinthus populi), to 

 the kitten moth (Cerura furcula), to the pebble prominent moth (Notodonta 

 z;/c;rflc), and to'various species of Clostera, (the chocolate-tipped moths), which 

 feed exclusively on the poplar and willow. The larva of Smerinthus populi 

 (Mag. Nat. Hist., viii. 629.) is very common both on poplars and willows, 

 and often strips them entirely of tiicir foliage ; the moth of this species is 

 seldom seen, as it flies but little, and only during the night. The larva of 

 Smerfnthus ocellatus is common on willows and poplars from July to the end 

 of September, and the fly does not usually appear till the following spring. 

 It is stated of this insect, that a female produced young without having any 

 connexion with the male ; from which it would appear that in certain Lepi- 

 doptera a single pairing can render fertile more than one generation, as well 

 as in the case of the vVphides. (Mag. Nat, Hist., viii. 357.) Trochilium api- 

 forme (the hornet hawk moth) and ^geria «silif6rmis feed on the Lombardy 

 poplar, on which the larva may be found in May and June, early in the morn- 

 ing ; the fly almost invariably mounts to the top of the trees soon after sunrise. 

 {Il)id., p. 5.55.) The splendid European butterfly (not yet detected in Great 

 Britain), Limenitis populi, frecjuents the aspen. The caterpillar, also, of the 

 line (^amberwell beauty, or, as it used to be called, the poplar butterfly, feeds 

 on the poplar. Both poplars and willows, when the trunks begin to decay, 

 are attacked by the jet ant (Formica fuliginosa), more especially in France, 

 and on this insect that very shy bird, the hoopoe chiefly lives. Among the 

 coleo|)terous insects, Rhynchites populi, Chrysomela populi and C. treiiudae, 

 iS'aperda popi'ilnea, and Orchestes p6[)uli, one of the flea weevils, feed on the 

 leaves of poplars. Notices of all the i)receding insects, and of various others 

 which attack the poplar and the willow, will be found in the Magazine of 

 Natural History, vols. i. to ix. inclusive. Various epiphytical fungi are found 

 on the poplar, some of them on the leaves, and others on the bark of the 

 branches or trunk ; such as Sclerotium yjopulinum Prrs., £rysiphe adiinca 

 Link and E. /populi Link, Erineum aureum Pcrs., L'redo ;K)|)ulina Pers., 

 and U. ovata Straus. Some others will be noticed under particular species; 

 and the greater part arc included among the Cryptogamia of our Encyclo- 

 jKcdia of Plants, where several of the species are figured. 



1 1 . P. a'i.ba L. The white Poplar, or Abclc Tree. 



hlfntification. Lin. Sp., 14fiJ. ; Willd. .Sn. PI., 4. p. 802. ; Smith Eng. Bnt., t. Ifil8. ; Eng. Fl, 4. 



p. 'J+.i. ; Hook. Brit FI., ed. 2., |). 43i.'. ; JVIackay FI. Hibern., pt 1. p. 2>t. ; Raii Syn., 446. ; Gcr. 



Enum., U8<;. ; B.iuh. Hist., 1. p. 2. (ig. IfiO. # 



S'linonyw.s. P. ftlba latifT.lia Lob. Ic, 2. p. IP.5. fig. 1. ; Pipulus No. IftU Hall. Ilisl., 2. p. 303. ; 



/'. m.^jo^ Mill. Did., 8. No. 4. ; P. nivca m/ld. Arb., 227. ; P. 6lba nivca Mnrt. Milt. The name 



