1.odp

講義下載

林產學 （木材組織學）

吳志鴻 (Jyh-Horng (Jyh Horng Wu)

Department of forestry

講義下載

Jyh--Horng Jyh Horng Wu Wu

木材之概念 何謂木材 (wood)? (wood)? 凡取材自木本植物 凡取材自 木本植物 (woody (woodyplant) plant)之莖 之莖(stem; (stem; also also called trunk or bole)、枝 、枝 枝枝 (branch) (branch) (branch) 和根 和根(root) (root)剝除樹皮 剝除樹皮 (bark) 之部分，皆稱之木材 之部分，皆稱之木材(wood) (wood)。。

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

The Tree

The Tree

Outer bark ob : outer bark ob: ib:: inner bark ib vc:: vascular vc cambium pp: : pith pith

Inner bark Vascular cambium

Macroscopic view of a transverse section of a Quercus alba (White Oak ) trunk. trunk.

Jyh--Horng Jyh Horng Wu Wu

The Tree

Jyh--Horng Jyh Horng Wu Wu

The Tree

Outer bark provides mechanical protection to the softer inner bark, and also helps to limit evaporative water loss.

The sapwood is the active, “living” wood that is responsible forconducting conductingthe thewater water(or (orsap) sap)from from the roots to the leaves. leaves

I Inner bbark k ((phloem phloem) hl ) iisth thetitissueththrough h hi which h sugars produced by photosynthesis (photosynthate or “f “food”) d”) are ttranslocated l t d ffromth thel leavest toththe roots or growing portions of the tree.

It has h not t yet t accumulated l t d th the often-colored ft l d chemicals that set apart the nonconductive h heartwood t d found f d as a core off d darker-colored k l d wood d in the middle of most trees.

The vascular cambium is the layer between between the the bark bark and the wood that is responsible for producing both these tissues.

The pith at the very center of the trunk is the remnants of the early growth of the trunk, before wood was formed

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

The Tree

Vascular Cambium Composition

Cambial cell division Division parallel to the stem surface in a tangential plane that results in formation of either xylem or phloem cells is calledpp p periclinaldivision periclinaldivision((平周分裂 平周分裂)). Production of new initials by radial partitioning is termed anticlinaldivision anticlinaldivision ( 垂周分裂 ). )

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Three Distinct Surfaces of Wood

Growth Rings Growth in temperate zones was characterized as proceeding p g rapidly rapidly p y in in early early y pspring spring g andslowing slowing gginin late summer before ceasing in the fall. Thiskikind Thi d of f growth th pattern tt usually ll results lt i thin the formation of one one growth growth ring ring annually annually and more or less distinct layers of early-and late-formed wood within each ring.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood Growth Rings

Growth Rings

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Growth Rings

The latewood latewood tissue tissue is of greater density, being composed of cells of relatively small radial diameter, with thick walls and small lumens. Latewood forms the darker darker-colored colored portion of the growth ring.

Growth Rings

Growth rings do not always appear as distinct alternating bands of early-wood and latewood. Some temperate hardwoods, for example, form l large-diameter di t pores early l i in a growing i season and much smaller pores later in the year; such woods we called ring ring-porous porous.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Growth Rings

Growth Rings

Other hardwoods exhibit little variation in cell structure across a growth increment, thus forming rings that are difficult to detect. B Because th the pores are about b t th thesame samesize isize through-out the growth ring, these woods are termed diffuse--porous diffuseporous.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Growth Rings

Jyh--Horng Jyh Horng Wu Wu

Growth Rings

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood Discontinuous rings

Discontinuous rings Growth rings sometimes fail to form around the complete cross section. This is a result of the cambium cambium remaining remaining dormant dormant in one or more places around the stem. stem Discontinuous rings are occasionally found in trees havingoneone-sided crowns and inheavily heavily defoliated, suppressed, defoliated suppressed pp andovermature overmaturetrees trees (Kramer and Kozlowski 1979). Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood False rings

False rings Occasionally, normal seasonal growth is interrupted by an event such asdrought, drought , late frost, frost , or ordefoliation defoliation by by insects insects or or hail. hail If such an event results in slowing or cessation of terminal growth,auxin auxinproduction production will will be be reduced d d and d may cause latewood-type l t dt cells ll tto be produced.

Jyh--Horng Jyh Horng Wu Wu

If events that cause slow growth are followed in the same growing season by conditions favorable to growth, normal growth patterns may be resumed, resumed accompanied by production of large and thin-walled earlywood cells (Kozlowski and Pallardy 1997b). 1997b) Casual observation of an annual ring formed under such circumstances will show two rings to have formed in a single g yyear. The ring g thus created is called a false ring. ring Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

False rings

False rings

False rings of conifers can usually be distinguished from normal growth ringsbyby examining latewood to earlywood yy transition( (Panshin and de Zeeuw 1980). Normal growth growth rings rings are characterized byan an abrupt p change g in cell size and wall thickness from the last-formed latewood of one seasonal ring to th earlywood the l d off th the next. t

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Normal rings

False rings

False rings exhibit agradual gradualchange changeinincell cell character on both sides of the false latewood, latewood resulting in a double gradation.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood Heartwood and sapwood

Heartwood and sapwood

The precise cause of heartwood formation continues ti tto bbeddebated, bt d b but t ddeath th off cells ll i is known to be related to at least two events: reduction of water content of cells especially (especiallyinin softwoods) and species-dependent biosynthesis softwoods of compounds termed secondary secondary metabolites. metabolites Secondary metabolites (extractives extractives) are defined as substances that do not participate directly in tree growth and development.

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood Heartwood and sapwood

Heartwood formation is often marked by are reduction in water content of cells.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood Heartwood and sapwood

The basic basic cell cell structure structureisisunchanged unchangedin the transformation to heartwood and thatthe theprimary primary change is the presence of extractable chemicals. chemicals One structural change sometimes associated with heartwood formation in softwoods isaspiration aspiration ofof many of the bordered pits intracheids. tracheids

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Properties of heartwood

Rays

1. Heartwood may be darker in color than sapwood. 2. Heartwood may be highly decay-decay ororinsect-insect resistant or both. resistant, both 3. Heartwood may be difficult to penetrate with li id ((such liquids h as chemicals h i l used d t to h help l preserve it) it).

Rays providean anavenue avenueby which sap sap can travel horizontally either to or from the phloem layer. In some hardwoods such as oak, oak rays are quite large and readily visible in a cross section.

4. Heartwood may be difficult to dry.

Large rays of oak are readily visible even without magnification.

5. Heartwood may have a distinct odor. 66H 6. H Heartwood t d may h have a slightly li htl hihigher h weight weight--per i ht per-unit volume than sapwood. Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Rays

Jyh--Horng Jyh Horng Wu Wu

Rays

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Rays

Rays

Many highly i valued hardwoods usedf for paneling i and furniture and other decorative purposes are characterized by distinct ray patterns on radial and tangential surfaces

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Knots

Knots

Knots intergrown ortight tightknot knot

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Macroscopic Character of Wood

Knots

Knots

Knots

loose or encased encased knots knots

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Macroscopic Character of Wood

Wood Structure

Knots

Artificialpruning pruning( 修枝 ) is sometimes used on valuable trees (to obtainclear clearlumber). lumber

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Cell Wall

Cell Wall Layering

Layering S2

S1

S3

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Cell Wall

Cell Wall Layering

The S1 S1 as a wall layer consisting of a few lamellae of a o alternating e a g SS SS and a ad and dZZ helical ehelical ca oorientation. eorientation ao.

Spiral direction of microfibril ZZand microfibril, andSSspiral spiral 50oo--70 70ooto the long axis

After a few layers form in this way, the orientation begins to change (S2 S2 layer); layer microfibrils spiral about the cell at a much smaller angle to the cell ooto 30oo(A ZZ helical orientation axis, varying from1010 exists i t i inththe t tracheids h id fof most t ft softwood). d) Just prior to final development of the cell, a change in orientation again occurs (S3 S3 layer), layer with the last several layers arranged similarly to the first oo f few layers, l th that t i is,6060 --90 90ooto t th thel long axis, i and d th the orientation is also alternating SS and ZZ. Thus the secondary part of a cell wall has three more or less distinct layersS1, (S1, S2,S2, and and S3S3 layers). layers

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Softwood S S Structure

Cell Wall Layering

Cell wall layers

PS: each lamellae about 60-70 µm thick

Jyh--Horng Jyh Horng Wu Wu

Longitudinal Tracheids The great majority of softwood volume, volume 90 90--95 9095 95 percent, is composed percent of long, slender cells called longitudinal tracheids. tracheids Such cells are oriented parallel to the stem axis. axis

Jyh--Horng Jyh Horng Wu Wu

Longitudinal Tracheids Configuration Longitudinal L it di l tracheids are about one hundred times greater in length than in diameter and are rectangular in cross section. section

Cell orientation in a standing softwood.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Longitudinal Tracheids Configuration

Tracheids have hollow centers (lumens) but are closed at the ends, and their shape is blunt or rounded radially and pointed tangentially. The are Th pits it i int tracheids h id normally bordered. The tracheid is much smaller, averaging g g only y 25--45 2545 µµ µm µminin diameter and 33--5 5 mm mm in inlength. length Jyh--Horng Jyh Horng Wu Wu

Longitudinal Tracheids Tracheids Cell wall sculpturing

Pit regions are much more readily penetrated by fluids and gases than are unpitted zones; thus pitpit pairs i are the th the primary primary i avenues avenues of fof cell cell ll l lumenlumen -to tt tolumen transport. transport

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Longitudinal Tracheids Tracheids Cell wall sculpturing

Cell Wall Cell wall sculpturing

In softwoods, softwoods thepit pitmembrane membranebetween two bordered pits differs from that separating a simple or half-bordered pit pair.

Cell Wall Cell wall sculpturing

The membrane center becomes thickened through accumulation accu u a o oofde densely se y pac packed ed a d and so sometimes e es circularly arranged microfibrils.  This thickening is called thetorus. torus torus  The area surrounding the torus is named the margo, margo and d it too t b becomes diff different t ffromth the normal l primary wall. A net of radially radiallyarranged arranged microfibrils may form over the existing primary wall, connecting the torus to the pit exterior. exterior

Jyh--Horng Jyh Horng Wu Wu

Cell Wall

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Cell wall sculpturing

Bordered pits are structurally similar in hardwood and softwood so ood spec species es e except e except cep cep that a the e membranes membranes e b a es aare e quite different. Membranes of all pit combinations inhardwoods hardwoodsare similar to those characterizing simple simple and and halfhalf bordered pit p ppairs in softwoods. softwoods Hence, no torus develops and there isnonodissolution dissolution of portions of the primary wall. wall In such an unmodified wall, it has been reported that no openings are visible, visible even at magnifications of x 100,000 . Jyh--Horng Jyh Horng Wu Wu

Longitudinal parenchyma A small portion of the volume of some softwoods is composed of longitudinally oriented parenchyma cells. When mature, these cells have the same general shape h as llongitudinal it di l ttracheids, h id lth although h ththey often subdivide a number of times along their l length th b before f fforming i secondary d walls. ll The result is that mature p parenchyma y usually y occur as longitudinal strands of short cells butted end-to-end in series. Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells Longitudinal parenchyma

The thin-walled and simple pitted parenchyma account for as much as11or or22 percent of the volume of some softwoods. softwoods

Other Longitudinal Cells Longitudinal parenchyma

As viewed in the transverse section ti th the axial i l parenchyma h cells may be widely scattered among the tracheids. i In that case the parenchyma is said to be diffuse diffuse (( 散點狀薄膜細 散點狀薄膜細 胞胞 )). )) g 落葉松、銀杏、粗榧、羅漢松、 e.g. 扁柏、圓柏、肖楠等屬 扁柏

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells Longitudinal parenchyma

If the cells are sufficiently numerous to be loosely y grouped in a row or a band extending concentrically in a growth ring (i.e., tangentially), the parenchyma is termed banded (formerly called metatracheal metatracheal) (帶狀或或切線狀薄 帶狀 切線狀薄 膜細胞 ). e.g. 鐵杉、柳杉、花柏、羅漢松、 圓柏、肖楠、穗花衫、紅檜 紅檜等 Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells Longitudinal parenchyma

If the cells are confined to the outer margins of the growth ring, i.e., to the last-formed or firstformed rows of cells, they are called terminal terminalor marginal marginal (( 輪輪 緣狀或或端生薄膜細胞 緣狀 端生薄膜細胞 )). e.g. 鐵杉 鐵杉、落葉松、台灣油杉、威 落葉松 台灣油杉 威 氏帝衫、圓柏、巒大衫 ( 香杉 ) ，及 部分杉科及柏科之木材

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Other Longitudinal Cells

Longitudinal parenchyma

Epithelium 周邊組織 ( 周邊組織 ) Structures known asresin resincanals canalsare found in certain softwood species. p They are consistently found in the genera Pinus Pinus (pines), Picea Picea (spruce), Larix Larix (larch), and Pseudotsuga (e.g., (e g Douglas Douglas-fir); fir); this thisisisone oneother other feature that assists in the identification of softwoods.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Other Longitudinal Cells

Epithelium

A resin canal canalis an an intercellular space surrounded by specialized parenchyma cells that secrete resin into the canal. Normal longitudinal resin canals are always y accompanied by horizontal canals, which occur in some of the rays. Jyh--Horng Jyh Horng Wu Wu

Epithelium

This resin is believed to play an important role in the healing of damaged tissue and in repelling attack by insects or other would be invaders ( 入侵者 .) would-be A cut through the inner bark of pine, for example, begins a flow of resin to the wound area and may even be accompanied p byyproduction p of new resin-producing cells near the wound. Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Other Longitudinal Cells

Epithelium

Epithelium

Florida (ca. early 1950's)

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Other Longitudinal Cells

Epithelium

Epithelium

Traumatic resin canals 傷癒樹脂溝 ( 傷癒樹脂溝 )) Resin canals in coniferous woods are of two kinds, those normal normalto the wood ((i.e., Normal Normal resin resin canals) canals )

Production of resin canals in response to injury or other traumatic events is not restricted to those genera that produce resin canals of the normal type. type

and those that presumably arise as a result of wounding and hence are termed traumatic (i.e., (i(i.e., (ie e Traumatic resin canals ))

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Other Longitudinal Cells

Epithelium

Epithelium

They may be longitudinal or transverse (longitudinal longitudinal and transverse traumatic canals seldom occur in the same sample). sample The longitudinal traumatic resin canals are generally arranged inaatangential tangentialrow rowthat may extend for an inch or two along a ring. Usually they are restricted to the earlywood earlywood increments portion of the growth increments.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Other Longitudinal Cells

Rays

Epithelium

The epithelial cells of traumatic au a c es resinca canals as as a rule are thickwalled

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

A coniferous wood may have either one or two types of rays. When normal resin canals are absent the rays are usuallyuniseriate uniseriate( 單列木質線 ), as viewed in the tangential plane. The presence of transverse resin canals (which are i invariably i bl accompanied i db byllongitudinal it di l canals) l) results in formation of fusiform fusiform rays( 紡錘形木質線 ), rays so called because of their spindle shape when cut transversely. Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays Rays of redwood are typically two cells in width (biseriate biseriate) ( 雙列 木質線 ).

Rays If a ray contains both ray trachieds (RT) and ray parenchyma (RP), then it isHeterocellular. Heterocellular If it has only one of the cell types, itHomocellular. is Homocellular True firs and cedars.

The cells composing softwood rays y may y be either ray ray parenchyma or ray ray tracheids. tracheids Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

Ray tracheids tracheids Ray y tracheids are similar to longitudinal g tracheids in that they havethick thickcell cellwalls wallsandbordered borderedpits. pits In the hard hard pines pines (ponderosa, lodgepole, jack, red, and southern), ray tracheids form secondary walls that are locally thickened in the vicinity of pits. The ridgelike thickenings look much like teeth extending into the lumen. Such tracheids are calleddentate dentateray raytracheids. tracheids Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays Ray parenchyma Ray y cells of thepparenchyma y yp type, , maybe y either thin or thick walled. Very thin-walled ray parenchyma commonly form no pitting, whereas simple pits typically perforate the thicker-walled variety of ray parenchyma cells. The shape, shape size, size and arrangement of pits in the cross fields vary in different coniferous woods and are therefore th f of f considerable id bl iimportance t i inth the identification of softwoods.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays Numerous pits interconnect ray cells; these are bordered pairs between ray tracheids, simple pairs between ray parenchyma (of the thickened variety), and half-bordered pairs between ray parenchyma and ray tracheids. Pitting on the ray sidewalls connects pits to longitudinal cells. Crossfield pitting 分野壁孔 ( 分野壁孔 ) occurs at the intersections of longitudinal tracheids and ray parenchyma, h and d the th hhalf-bordered lf b d d pits it are of f unique form.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays (a) WindowWindow-like pits (窗型壁 ), or fenestriform fenestriform 孔孔 They are found in the commercial soft pines (eastern white pine, sugar pine, western white pine)) and in red ppine; p also in Scotch pine and in a number of other exotic species of conifers.

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

(a) WindowWindow-like pits (窗型壁孔 ), or fenestriform fenestriform

(b, c) Pinoid pits( pits(松型壁孔 )) Pinoid pits differ from the window-like pits by being smaller, more variable in size, and more numerous per cross field.

Eastern White Pine Jyh--Horng Jyh Horng Wu Wu

Red Pine

Pinoid Pi id pits it ffeature t all all ll native hard pines, pines other other than red pine. pine

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays Wood identification

(b, c) Pinoid pits( pits(松型壁孔 ))

Eastern white pine pine, Red pine, pine and Pitch pine? (Soft pine) (Hard pine) (Hard pine)

Southern Yellow Pine

Shortleaf Pine

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays (d) Piceoid pits ( 雲杉型壁孔 )) They are small bordered pits, generally elliptical in shape, with a narrow (linear) and frequently slightly extended aperture. p Pits of piceoid type are found in Picea, Picea Larix Larix, and Pseudotsuga. Pseudotsuga

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

(d) Piceoid pits (雲杉型壁孔 ))

(e) Taxodioid pits pits ((杉木型壁 )) 孔孔 Pits of this type feature the Taxodiaceae (杉科 杉科), i.e., Sequoia (長葉世界爺 長葉世界爺 屬屬 ) and Taxodium 落羽松 ( 落羽松 屬屬 ))

Eastern Spruce

Taxodioid pits also are present in Abies 冷杉屬 ( 冷杉屬 ) and Thuja ( 側柏屬 ).

Red Spruce

Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

(e) Taxodioid pits pits ((杉木型壁孔 ))

(f) Cupressoid Cupressoidpits pits ((柏木型壁 )) 孔孔 Cupressoid pits are found in Chamaecyparis ( 扁柏 屬 ), Juniperus ( 圓柏屬 ), Calocedrus ( 肖楠屬 ), and ) ), and are Taxus(( 紅豆杉屬 occasionally present in Tsuga (鐵杉屬 鐵杉屬).

Redwood Jyh--Horng Jyh Horng Wu Wu

White Fir Jyh--Horng Jyh Horng Wu Wu

Rays

Rays

(f) Cupressoid Cupressoidpits pits ((柏木型壁孔 ))

Incense--Cedar Incense

Eastern Redcedar

Jyh--Horng Jyh Horng Wu Wu

Rays

Jyh--Horng Jyh Horng Wu Wu

Summary

(g) Araucarioid pits (南洋杉型壁孔 )) The individual pits are predominantly cupressoid, but their arrangementininalternate alternate rows of usually y three or more with a tendency for crowding. Araucarioid crosscross-field field pitting is restricted toAraucariaceae Araucariaceae(( 南南 (Agathis,, Araucaria, Araucaria, 洋杉科) (Agathis Wollemia). Wollemia ). Jyh--Horng Jyh Horng Wu Wu

Jyh--Horng Jyh Horng Wu Wu