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IRISH GARDENING. 



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Magnolia Kobus at Eostrevor House. 



Pinus excelsa. 



By Pkofessor A. Henhy, M.A., Eoyal College 



of Science, Duljlui. 

 Before giving an account of this species, which 

 is one of the white pines, it "seems advisable 

 to draw attention to the general characters 

 of the genus Pinus, of which there are no less 

 than 70 species, spread over the northern hemi- 

 sphere. Pines are distinguishable from all 

 other conifers by their adult foliage, which 

 consists of clusters of 2, 3, 4 or 5 needle-like 

 leaves. Each cluster is surrounded at its base 

 by a sheath; and just below its origin on the 

 branch there is a scaly bract. The nature 

 of these bracts, and the persistence or the 

 speedy fall of the leaf -sheaths are important 

 points in dividing the genus into sections. 

 The two main classes of pines are the hard 

 pines, with hard reddish wood, and the soft 

 pines, with soft white wood. The branchlets 

 of the former are roughened by the raised de- 

 current bases of the bracts; but in the soft 

 pines the branchlets are smooth. The structure 



of the cones and seeds is also very varied. 

 The cones of spruce, larch, and silver fir ripen 

 in one season ; but those of j^ine take two years 

 to ripen; and, as a result, there is on each 

 of the scales of the cone a small dark-coloured 

 area, called the umbo, which is the portion of 

 the scale that grew during the first season, 

 the rest of the scale being the growth of the 

 second season. The seeds of some pines have 

 long wings, so that they can fly in a. current 

 of air for a long distance. In other pines the 

 wings of the seeds are short and ineffective, 

 or absent altogether. In the latter case the 

 seeds become large and edible, and are dis- 

 criminated by rodents, crows, &c., who eat 

 some and carelessly drop others which germi- 

 nate at a distance from the parent tree. 



From these prehminary observations it can 

 be seen how the various sections of the genvis 

 Pinus differ from one another in the characters 

 of the leaves, branchlets, buds, cones, seeds, 

 &c. In this article we can only deal with one 

 section, the white pines, which belong to the 

 main division of soft pines with white wood 

 and smooth branchlets. The white pines have 

 clusters of five leaves, the sheaths of which 

 quickly fall off. Their cones are elongated, on 

 long stalks, and composed of numerous thin 

 scales, each of which has a terminal umbo. 

 The seeds have adherent long wings. The white 

 pines comprise seven species, distinguishable 

 as follows : — 



I. — Branchlets without hairs. 



1. Pinus excelsa. Leaves 5 or 6 inches long, 

 drooping or spreading. Himalayas. 



2. Pinus Peuke. Leaves 4 inches long, erect, 

 not spreading. Balkan Mountains. 



II. — Branchlets more or less hairy. 



3. Pinus AyacahVute, Branchlets with very 

 short rusty pubescence. Leaves, 5 or 6 inches 

 long, drooping or spreading, like those of P. 

 excelsa. Mexico. 



4. Pinus Lambertiana. Branchlets with 

 short brown hairs. Leaves 4 inches long, 

 twisted a complete turn, rigid, ending in a 

 sharp point. California, Oregon. 



5. Pinus inonticola. Branchlets with short 

 brown hairs. Leaves 4 inches long, twisted 

 slightly in their upper half, blunt at the apex. 

 Western North America. 



6. Pinus Strobus. Branchlets with a minute 

 tuft of hair?, below the insertion of each leaf- 

 cluster. Leaves 3 inches long, not twisted. 

 Eastern North America. 



7. Pinus pptrviflora. Branchlets with a 

 scattered mii uite pubescence. Leaves 2 

 inches long, w'Dite on the inner surface. Japan, 

 Formosa. 



