. Agricultural botany, theoretical and practical. Botany, Economic; Botany. 134 ANATOMY OF STEM, ROOT AND LEAF Cut longitudinal sections of the same ; examine and make sketches of the various i^arts. ,, , . Ex. 66.—Cut and examine in a similar manner young one-year-old snoots of beech, oak, elm and ash trees. j , « Also-make and compare under a low power, transverse, radial and tan» gential, longitudinal sections of pieces of the common timbers. In the following tables are given the characters of the common timbers, which can be easily distinguished with the naked eye and a pocket lens :— I.—T
. Agricultural botany, theoretical and practical. Botany, Economic; Botany. 134 ANATOMY OF STEM, ROOT AND LEAF Cut longitudinal sections of the same ; examine and make sketches of the various i^arts. ,, , . Ex. 66.—Cut and examine in a similar manner young one-year-old snoots of beech, oak, elm and ash trees. j , « Also-make and compare under a low power, transverse, radial and tan» gential, longitudinal sections of pieces of the common timbers. In the following tables are given the characters of the common timbers, which can be easily distinguished with the naked eye and a pocket lens :— I.—TIMBER OF CONIFEROUS TREES. In these timbers the annual rings are very distinct (Fig. 63), the autumn- wood is hard and dark-brown or reddish in colour, and sharply marked off from the spring-wood, which is soft and much paler in tint. Neither medullary rays nor porous rings are visible. 1. Heart-wood same colour as the Splint-wood. (a) Silver Fir (Abiespectinata D. C). (b) Common Spruce {Picea excelsa Lk.). Both these are soft 'white woods,' pale yellowish or reddish-white in colour. The spruce possesses a few fine resin ducts in its autumn-wood which may be seen in cross-sections as very small light spots: they are missing from the wood of the Fig. 63.—Transverse sec- ^ cjlvpr fir tion through annual rings of Sliver nr. larch timber. (Four times 2. Heart-wood in Old dry timber, reddish-ljrown; natural size.) splint-wood, pale yellow. (a) Larch (Larix europaa D. C). Rings of autumn-wood dark red and very distinct. The branches arise irregularly on the stem, so that the knots on larch boards are scattered irregularly. {b) Soots Pine [Pinus sylvesiris L.). Rings of autumn-wood not so' dark as larch, and contains larger, more distinct resin-ducts. The branches arise in whorls at regular intervals, and the knots are similarly distributed on boards cut irom this tree. II.—TIMBER OF DICOTYLEDONOUS TREES. GROUP A. Vessels of the spring-wood of each annual ring visihle to t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
