SILVA OF NORTH AMERICA. 



CONIFERS. 



1 Henry, Nov. Act. Acad. Cces. Leop. xix. 93, t. 12 ; xxii. pt. i. 

 247, t. 23. 



2 Pinics rigida and Pinus echinata are the species of the United 

 States which generally bear primary leaves on branches, or pro- 

 duce freely shoots from the stumps of cut trees. These shoots, 

 which are clothed with primary leaves, grow vigorously for a few 

 years and then usually perish. On the sandy sterile plains in 

 Burlington and Ocean Counties, New Jersey, however, the coppice 

 growth over large areas is principally composed of such stump 

 shoots. They are usually destroyed at the end of a few years by 

 fires which do not kill the stumps ; and these often live to a great 

 age, producing successive crops of shoots, and show the wonderful 

 recuperative power of these trees under what would seem to be 

 most unfavorable conditions. (See Fernow, Garden and Forest, 

 viii. 472 ; x. 209.) 



3 Near Bluffton, South Carolina, Dr. J. H. Mellichamp has no- 

 ticed two trees of Pinus heterophylla producing during several 

 successive seasons well developed pistillate flowers at the tips of 

 the staminate flowers (Christ, Bull. Soc. Bot. Belg. xxxiii. pt. ii. 

 88. —J. G. Jack, Garden and Forest, viii. 222, f. 33, 2). 



4 The pollen of Pinus can float in the air for a long time, and is 

 sometimes wafted great distances by the wind. Engelmann ( Trans. 

 St. Louis Acad. iv. 169) found after a southern storm in March 

 Pine pollen in the streets of St. Louis which must have been car- 

 ried from the forests of Pinus palustris on the Red River, a distance 

 of four hundred miles in a direct line ; and the decks of vessels off 

 the coast of the south Atlantic states are sometimes covered with 

 Pine pollen in early spring. 



5 According to Celakovsky, the umbo of the cone-scale of Pinus 

 is the apophysis of the scale of the first year, which becomes woody 

 and ceases to grow at the end of the first season, the apophysis of 

 the mature cone being developed the second year from tissue at 

 the base of the umbo (Oesterr. Bot. Zeitschr. 1893, 314, t. 14, f. 11- 

 14). 



6 In germinating the empty hood-like testa of the Pine seed from 

 which the wing has usually fallen is raised on the tip of the coty- 

 ledons ; the axis soon commences to elongate and to bear primary 

 leaves from whose axils the clusters of foliage leaves begin to ap- 

 pear in the second season, although in the case of Pinus palustris 

 of the southeastern United States, as noticed by Engelmann, the 

 axes during six or eight years thicken without elongating and bear 

 in the axils of the primary leaves numerous clusters of long sec- 

 ondary leaves (I. c. 174). 



7 By Engelmann (Z. c. 175) the species of Pinus are grouped in 

 the following sections, his arrangement being based on the form of 

 the cone-scales, the internal structure of the leaves, and the posi- 

 tion of the cones : — 



Sect. 1. Strobus. Cones subterminal ; exposed part of the 

 cone-scales thin, rarely reflexed, furnished with a marginal unarmed 

 umbo. Leaves in 5-leaved clusters, the sheaths loose and decidu- 

 ous. Anthers terminating in a, knob, in a few teeth, or in a short 

 crest. Wood soft and light-colored. White Pines. 



Eustrobi. Leaves sharply serrulate or rarely nearly entire ; 

 resin ducts peripheral. Inhabitants of eastern and western 

 North America, Mexico, Japan, the Himalayas, and southeastern 

 Europe. 



CEMBRiE. Leaves sparingly serrulate ; resin ducts parenchy- 

 matous. Inhabitants of northeastern and northern Asia and cen- 

 tral Europe. 



Sect. 2. Pinaster. Exposed portion of the cone-scales thick- 

 ened, the dorsal umbo usually aristate. Leaves in from 1 to 5- 

 leaved clusters, the sheaths usually persistent. Anthers generally 



terminating in semiorbicular or nearly orbicular crests. Wood 

 hard, heavy, and resinous. Pitch Pines. 



Integrifolle. Cones subterminal, their scales thick, un- 

 armed or in one species furnished with long slender awns. 

 Leaves in from 1 to 5-leaved clusters, entire ; resin ducts pe- 

 ripheral. Anthers terminating in a knob or in a few teeth. 

 Inhabitants of western North America and of northern Mexico. 



Sylvestres. Cones subterminal. Leaves in 2 or 3-leaved 

 clusters, serrulate, the sheaths persistent ; resin ducts peripheral. 

 Anthers crested or in one species knobbed. Inhabitants of 

 Europe, southeastern Asia, the Philippine Islands, and eastern 

 North America. 



Halepenses. Cones lateral, their scales much thickened with 

 prominent umbos or smooth. Leaves in 2 or 3-leaved clusters, 

 the sheaths deciduous or persistent ; resin ducts peripheral. In- 

 habitants of northern China, the northwest Himalayas, and the 

 basin of the Mediterranean. 



PoNDEROSiE. Cones subterminal, their scales umbonate. 

 Leaves in 2, 3, or 5-leaved clusters, the sheaths persistent or 

 deciduous ; resin ducts parenchymatous. Inhabitants of western 

 North America, Mexico, the Canary Islands, southern Europe, 

 and Japan. 



Tmdje. Cones lateral, their scales much thickened, and armed 

 with stout and persistent or with weak deciduous prickles or 

 with stout elongated hooked or twisted spines. Leaves in 2 or 

 3-leaved clusters, the sheaths persistent ; resin ducts parenchy- 

 matous. Inhabitants of eastern and western North America, 

 Mexico, and southern Europe. 



Atjstrales. Cones subterminal or lateral, their scales umbo- 

 nate. Leaves in from 2 to 5-leaved clusters, the sheaths decid- 

 uous ; resin ducts internal. Inhabitants of southeastern North 

 America, the West Indies, and Mexico. 



8 Parlatore, De Candolle Prodr. xvi. pt. ii. 378. — Engelmann, 

 I. c. 175. 



A tendency to hybridize has not been observed in the North 

 American species of Pinus ; but in Europe supposed hybrids be- 

 tween Pinus sylvestris and Pinus montana have been noticed in the 

 Swiss Engadine (see Christ, Flora, xlvii. 145, t. 1. — Beissner, 

 Handb. Nadelh. 230) ; and Mayr found in Japan what he believed 

 to be hybrids between Pinus Thunbergii and Pinus densiflora (Mo- 

 nog. Abiet. Jap. 83, t. 7, f. 2, 3, 4 ; 84, t. 7, f. 3, 4). 



9 A. Richard, Fl. Cub. iii. 233. — Grisebach, Cat. PI. Cub. 217. — 

 Sauvalle, Fl. Cub. 151. 



10 Morris, The Colony of British Honduras, 56. 



11 Pinus Canariensis, Buch, Phys. Beschr. Canar. Ins. 159 

 (1825). — De Candolle, PL Rar. Sard. Geneve, 1, t. 1, 2. — D. 

 Don, Lambert Pinus, iii. t. — Webb & Berthelot, Phytogr. Canar. 

 sect. iii. 280 ; Atlas, t. 6. — Forbes, Pinetum Wobum. 57, t. 21. — 

 Link, Linncea, xv. 508. — Antoine, Conif. 33, t. 15. — Endlicher, 

 Syn. Conif. 165. — Carriere, Traite Conif 348. — Gordon, Pine- 

 tum, 191. — Parlatore, I. c. 393. — Christ, Bot. Jahrb. ix. 172, 486 

 (Spicilegium Canar.). — Masters, Gard. Chron. ser. 3, iii. 723, 

 f. 94. 



Pinus Canariensis inhabits the mountains of Teneriffe, and at 

 elevations of from five to six thousand feet above the sea forms 

 extensive forests on Grand Canary Island. It is a tree seventy 

 or eighty feet in height, with a stout trunk covered by thick deeply 

 furrowed bark, a broad round-topped head of spreading branches, 

 slender dark green leaves in clusters of three and from eight to 

 ten inches in length, and oblong-ovate lustrous cones. It grows 

 with great rapidity while young, and has been largely planted in 

 the gardens of southern Europe and other warm countries. 



