IAWA Bulletin n.s., Vol. 6 (1),1985 23

THE ANATOMY OF THE BARK OF LlBOCEDRUS IN NEW ZEALAND

by

Lek-Lim Chan'" School of Forestry, University of Canterbury, Christchurch, New Zealand

Summary The anatomy of the bark of Libocedrus bid­ southwards. In South Island it is also found in willii and L. plumosa, both indigenous to New lowland forests in the west. Libocedrus plumosa Zealand, is described. The phloem cell types in­ is also a tall tree and is found in lowland forest clude axial and ray parenchyma, sieve cells and from 35° to beyond 38° S in North Island and fibres. Fibres are of two types, thin-walled and between Collingwood and Westhaven (NW. Nel­ thick-walled. The ends of these fibres are most­ son) in South Island. ly blunt or abrupt. Minute crystals (crystal sand) were found in Terminology the radial walls of some axial parenchyma cells, 'Conducting phloem' refers to that part of sieve cells and fibres. Trabeculae were abun­ the phloem close to the vascular cambium where dant in the bark of L. bidwillii. sieve cells are still functioning in conduction, The walls of the phellem cells were very thin, and 'living bark' designates that part of the appearing flimsy. Phelloderm cells in L. plumo­ bark outside the vascular cambium up to and sa seem to undergo sclerification just prior to including the last-formed periderm. death, upon formation of a new periderm deep­ All other terms used for tissues of the bark er in the phloem. are in common usage (see IA WA, 1964; Society Key words: Bark anatomy, crystals, Libocedrus, of American Foresters, 1958). trabeculae. The approximate size of crystals is given as a length which refers to the greatest length (or Introduction diameter) across the crystal. Information on the anatomy of bark is rela­ tively scanty, compared to that of wood. Only Materials and Methods a few extensive studies have been made on the Three trees each of Libocedrus bidwillii and bark of gymnosperms indigenous to New Zea­ L. plumosa were selected from Inangahua West land. and Omahuta State Forests respectively. Two Craddock (1932a) made a study of the barks specimens of the bark from opposite sides of of Podocarpaceae in New Zealand but only an each tree at breast height were collected. The abstract of this work was published (Craddock, specimens were immediately fixed in 5 % glutar­ 1932b). Robinson and Grigor (1963) examined aldehyde in 0.025 M phosphate buffer and left the origin of the periderm in some New Zea­ in the fixative until sectioning. land plants including eight members of the Podo­ Observations were made using optical (LM) carpaceae family and Agathis australis. Kucera and scanning electron (SEM) microscopy. For and Butterfield (1977) investigated the resin optical microscopy, sections (c. 30 J.Lm in thick­ canals in the bark of New Zealand Phyllocladus ness) were cut without embedding or further species. However, investigations on the bark of treatment on a Reichert 'OrnE' sledge micro­ the Cupressaceae indigenous to New Zealand tome from blocks of bark not bigger than 7 x 5 have never been carried out. This present work mm on the cutting face. Sections were picked is a continuation of an earlier report (Chan et up from the microtome knife with a fine hair aI., 1982). brush wetted with 25 % alcohol and then left in Two species of Libocedrus (Cupressaceae) a petri-dish with 45 % alcohol until stained. They occur naturally in New Zealand, namely L. bid­ were double-stained with safranin and fast green. willii and L. plumosa (Allan, 1961). This small Macerations were also carried out by heating genus has only three other species, all endemic match-stick size specimens in a solution of equal to New Caledonia (Dallimore & Jackson, 1966). amounts of glacial acetic acid and 20 volume Libocedrus bidwillii is a tall tree found in mon­ hydrogen peroxide in a water-bath for about tane to subalpine forests, distributed in both 1-2 hours. The tissue was then stained with North and South Island, from 36° 50' latitude 1.5% aqueous safranin, washed and teased out.

* Present address: St. Peter's College, P. O. Box 327, Kuching, Sarawak, Malaysia.

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 24 IAWA Bulletin n.s., Vol. 6 (1),1985

For SEM observations, the specimens were most with rather blunt or abrupt ends like pa­ prepared by hand, following the method out­ renchyma cells (Fig. 2C). Thin-walled fibres lined by Exley et al. (1974, 1977). It was neces­ have numerous slit-like pits. The walls of both sary to take the specimens through a progres­ thin- and thick-walled fibres are lignified, bire­ sive alcohol series and critical-point drying. For fringent and seem to be composed of two main examination of wall structure, soaking in 5% layers. The wall of thin-walled fibres consists of sodium hypochlorite prior to the alcohol series one very thin layer on the outside and one thin was required to remove cell deposits. Dried spe­ layer on the inside, while in thick-walled fibres cimens were coated with gold in a Polaron it consists of one thin layer on the outside and Diode Sputtering System E500 and examined one thick layer on the inside. Some minute in a Cambridge Stereos can 600. crystals « 4 J.Lffi long), mostly hexagonal pris­ matic in shape, are round in the radial walls of Descriptions fibres (in the region of the middle lamella). In all specimens studied, trabeculae were ex­ Libocedrus bidwillii Hook. f. tremely common, all traversing in the radial di­ The diameters at breast height of the trees rection from one tangential wall to the next were 65.6 cm, 13.7 em and 18.0 cm and the (Fig. 2B, D). thickness of the living bark at the same height The periderm consists of 2-3 layers of phel­ was 3.8 mm, 4.5 mm and 3.0 mm respectively. lem, one layer of phellogen and 2-3 layers of The phloem consists of sieve cells, axial and phelloderm. Phelloderm cells are oblong in TS ray parenchyma and fibres, arranged in regular and rectangular to oblong in RLS. In TLS, tangential rows (Fig. lA, B). Every row of axial those phelloderm cells cutoff by phellogen parenchyma cells always has a row of sieve cells derived from axial parenchyma cells appear on either side. These sieve cell-parenchyma­ rectangular to six-sided while those from ray sieve cell rows are separated by 1-2, rarely 3, parenchyma cells are rather isodiametric and rows of fibres (Fig. 1C). The conducting phloem smaller than the former (Fig. 3A). Phelloderm seems to be about 0.7-0.8 mm wide. cells have thin walls; some contain tannin, as Sieve cells appear rectangular in transverse do some phellogen cells. Phellem cells are rec­ section (TS), becoming narrowly rectangular in tangular in TS and RLS. In TLS, phellem cells the non-conducting phloem. Some minute crys­ are of two shapes corresponding to phelloderm tals « 4 p.ffi long), mostly hexagonal prismatic cells in TLS. Those phcllem cells derived from in shape, appear in their radial wall, bu t are some­ ray parenchyma cells often have some tannin times absent in the non-conducting phloem. contents while those from axial parenchyma Sieve areas are about 6-9 !lm in diameter, cells do not. Phellem cells are very thin-walled, mostly in the radial walls in single files. the walls appearing rather flimsy (Fig. 3B). Axial parenchyma cells are rectangular to Dead periderm and phloem are not exfoliated isodiametric in TS and rectangular in radial lon­ readily, leading to the formation of a thick rhy­ gitudinal section (RLS) and tangential longi­ tidome which consists of alternating layers of tudinal section (TLS). They are mostly filled dead periderm and phloem. Fibres and sieve with tannin. Some minute crystals « 4 J.Lffi cells remain intact but parenchyma and phello­ long), mostly hexagonal prismatic in shape, derm cells collapse markedly in the radial direc­ appear to be located in the radial wall of some tion (Fig. 3C, D). parenchyma cells but are sometimes absent in the non-conducting phloem. Libocedrus plumosa (Don) Sargent Phloem rays are uniseriate, rarely partly bi­ The diameters at breast height of the trees seriate, usually 1-7 cells high (up to 12 count­ were 33.4 cm, 41.5 cm and 39.5 cm, and the ed). The cells appear rectangular in TS and thickness of the living bark at the same height RLS, and round to elliptical (with long axes in was 3.8 mm, 4.6 mm and 3.8 mm respectively. the longitudinal direction) in TLS (Fig. 2A). The phloem comprises sieve cells, axial and Fibres are of two types, thin- and thick­ ray parenchyma and fibres, arranged in regular walled. They are mostly thin-walled with large tangential rows (Fig. 4A, B). Every row of axial empty lumina (Fig.lC, 2A). Thick-walled fibres parenchyma cells always has a row of sieve cells have very narrow lumina and are scattered in on either side. These sieve cell-parenchyma­ the phloem, rarely forming a tangential row sieve cell rows are usually separated by a row (Fig. lA, B, C). Both thin- and thick-walled of fibres (Fig. 4C). The conducting phloem is fibres appear square to rectangular (with long about \.6-2.0 mm wide. axes in the radial direction) in TS and elongated Sieve cells appear rectangular in TS with little with pointed ends in TLS (Fig. 2A). In RLS, change in the non-conducting phloem. Some some appear elongated with pointed ends, but minute crystals, mostly hexagonal prismatic in

Downloaded from Brill.com10/01/2021 11:02:14AM via free access IAWA Bulletin n.s., Vol. 6 (1),1985 25 shape « 4 JJ.m long) are found in their radial sponding to the two shapes of phelloderm cells walls in the conducting phloem. Sieve areas are in TLS. As in L. bidwillii, those phellem cells about 8-14 JJ.m in diameter, mostly in the ra­ derived from ray parenchyma cells often have dial walls in single files (Fig. 5A). some tannin contents while those from axial Axial parenchyma cells are rectangular to parenchyma cells do not. Phellem cells have isodiametric in TS and rectangular in TLS and very thin flimsy walls (Fig. 6E) similar to those RLS. They are mostly filled with tannin. Abun­ in L. bidwillii. dant minute crystals, hexagonal prismatic in Dead periderms and phloem are not readily shape « 4 JJ.m long), are located in the radial exfoliated but are accumulated as sheets on the walls of parenchyma cells in the conducting stem, leading to the formation of a thick rhyti­ phloem. dome comprising alternating layers of dead Phloem rays are uniseriate, rarely partly bi­ periderms and phloem. Fibres and sieve cells seriate and are 1-9 cells high (up to 12 count­ remain intact but most parenchyma cells col­ ed). The cells are rectangular in TS and RLS, lapse in the radial direction. Some parenchyma but sometimes appear constricted in TS at the cells appear to possess lignified thickened walls point where a ray crosses a tangential row of made up of a few to several thin to very thin fibres, especially thick-walled fibres (Fig. 4C); layers in which case the cells remain intact in TLS, round (Fig. 5B) to elliptical (with long (Fig. 7 A, B). Dead phelloderm cells appear sc1e­ axes in the longitudinal direction), the latter rified with polylamellate, lignified walls, re­ shape especially at areas where a ray crosses a maining rather isodiametric, growing larger tangential row of fibres. than the original cells (Fig. 7C, D). It therefore Fibres are of two types, thin- and thick-walled seems that just prior to death, phelloderm cells (Fig. 4C). Both types appear square to rectan­ and some axial parenchyma cells undergo gular (with long axes in the radial direction) in changes in wall structure. TS and elongated with pointed ends in TLS. In RLS, some fibres appear elongated with point­ Discussion ed ends (Fig. 5C); most, however, appear elon­ The arrangement of phloem cells differs be­ gated with rather blunt (Fig. 5D) or abrupt tween L. bidwillii and L. plumosa. Sieve cell­ ends, like parenchyma cells. Thin-walled fibres parenchyma-sieve cell rows in L. bidwillii are have large empty lumina and numerous slit-like separated by 1-2, rarely 3, rows of fibres but pits (Fig. 6A). Most thick-walled fibres have in L. plumosa usually by one row of fibres only. very narrow lumina and a lower number of pits Minute crystals « 4)J.ffi long) occur in the than the thin-walled fibres, giving rise to many radial wall of sieve cells, axial parenchyma cells blind pits between thick- and thin-walled fibres and fibres in both species of Libocedrus studied. (Fig. 6B). Minute crystals « 4)J.ffi long) some­ In L. plumosa these crystals do not occur in times occur in the radial walls of fibres, in the the wall of sieve cells and axial parenchyma region of the middle lamella (Fig. 6C). Both cells in the non-conducting phloem. In L. bid­ thin- and thick-walled fibres form tangential willii they are sometimes absent in the wall of rows. The walls of both thin- and thick-walled these two cell types in the non-conducting fibres are lignified, birefringent and seem to be phloem. Various researchers have mentioned made up of two main layers. The wall of thin­ the occurrence of such minute crystals (some­ walled fibres comprises one thin layer on the times referred to as 'crystal sand') in the wall outside and one very thin layer on the inside, of sieve cells and phloem parenchyma cells while in thick-walled fibres, it comprises one (Strasburger, 1891 ; Chang, 1954; Bamber, 1959; thin layer on the outside and one thick layer Esau, 1969; Chan, 1979, 1982; Parameswaran on the inside (Fig. 6D). & Liese, 1979; Franceschi & Horner, 1980). The periderm consists of 2-3 layers of phe1- The presence of crystals in the wall of phloem lem, one layer of phellogen and 2-3, occasion­ fibres was probably first reported by Moeller ally 4 layers of phelloderm (Fig. 6E). Phello­ (1882) in Taxus. Chang (1954) subsequently derm cells are thin-walled, rectangular to iso­ found them in the phloem fibre wall of Taxus diametric in TS and RLS. In TLS, those phello­ brevifolia Nutt., and Torreya californica Torr. derm cells produced by phellogen derived from Strasburger (1891), Chang (1954), Bamber axial parenchyma cells appear 4 -6-sided while (1959), and Chan (1979, 1982) indicated that those from ray parenchyma cells appear rather crystals occur specifically in the radial wall of isodiametric and smaller (Fig. 6F). Innermost phloem cells in some species. Esau (1969) sug­ phelloderm cells are invariably filled with tan­ gested that crystals are formed in the primary nin. Some phellogen cells are also filled with wall and subsequently become embedded in tannin. Phellem cells are rectangular in TS and small pockets in the secondary wall. Later, the RLS. In TLS, they are of two shapes corre- (text continued on page 32)

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 26 IAWA BUllet"mns ""' VI0" 6 (I), 1985

Downloaded from Brill.com10/01/2021 11:02:14AM via free access IAWA Bulletin n.s., Vol. 6 (1),1985 27

--y- -- -., :

c

Fig. 2 (above). Libocedrus bidwillii bark. - A: General view of phloem; TLS (LM) x 120. Rays (R); thin-walled fibres (F) with large empty lumina; thick-walled fibre (TF): axial parenchyma (P). Note the slightly elliptical shape of ray cells and pointed ends of fibres. - B: Phloem with abundant tra­ beculae (unlabelled arrows); RLS (LM) x 120. Thin-walled fibres (F); axial parenchyma (P); sieve cell (S). - C: Macerated thin-walled fibres showing abrupt blunt ends (arrows); (LM) x 240. - D: A trabeculum (arrow) traversing a sieve cell (S) and a thin-walled fibre (F); TS (SEM) x 2,000.

Fig. 1 (p. 26). Libocedrus bidwillii bark. - A & B: General view of living bark from vascular cam­ bial region (V) to the last-formed periderm (Pe); TS (LM) x 45. Top of Fig. 1A joins bottom of lB. Rays (R-R'); tangential rows of axial parenchyma (P); thin-walled fibres (F); scattered thick-walled fibres (TF): rhytidome (Rh). Unlabelled arrow in Fig. lB indicates thick-walled fibres in two tan­ gential rows which is not a common feature. Unlabelled arrow in lA shows approximately the ex­ tent of the conducting phloem from (V). - C: Living phloem showing the general arrangement of cells; TS (LM) x 250. Tangential rows of axial parenchyma cells (P) with a row of sieve cells (S) on either side, separated by 1 or 2 rows of fibres; thin-walled fibres (F) with large lumina; .scattered thick-walled fibres (TF) with very narrow lumina.

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 28 IAWA Bulletin n.s., Vol. 6 (1),1985

Fig. 3 (above). Libocedrus bidwillii bark. - A: Phelloderm cells; TLS (LM) x 240. Phelloderm cells produced by phellogen derived from ray parenchyma (arrows) are isodiametric and smaller than other phelloderm cells (Pd) produced by phellogen derived from axial parenchyma. - B: Phellem cells ; TS (SEM) x 1,050. Note the thin flimsy walls and also the rectangular shape. - C: Rhytidome; TS (LM) x 75 . Dead periderms (PE); thick-walled fibres (TF); thin-walled fibres (F); dead sieve cells (S); rays (R-r). All axial parenchyma cells (P) have collapsed. - D: Dead periderm; TS (LM) x 300. Phellem (PM) ; collapsed phelloderm (PD); dead sieve cells (S); collapsed axial parenchyma cells (L); thin-walled fibre (F); thick-walled fibre (TF).

Fig. 4 (p. 29). Libocedrus plumosa bark. -- A & B: General view of the living bark from vascular cambial region (V) to the last-formed periderm (PE); TS (LM) x 45 . Top of Fig. 4A joins bottom of 4B. Rays (R-r); tangential rows of thin- (F) and thick-walled (TF) fibres , and axial parenchyma (P)

Downloaded from Brill.com10/01/2021 11:02:14AM via free access IAWA Bulletin n.s., Vol. 6 (l), 1985 29

II .lNl .~ ~ ~ r ~ . \ ~ I~ ! ~ ~ M ~I.l ,~ ~ ,~ . , nllll H1'InI"'[ i( ~ R , ,11 , - :~• -

J

I P.....: ~~ lJcl1 ; F..... -~ ~l g , - f!j A v

with sieve cells on either side. Unlabelled arrow in Fig. 4A indicates approximately the extent of conducting phloem from (V). - C: Living phloem showing general arrangement of cells; TS (LM) x 120. Tangential rows of parenchyma cells (P) with a row of sieve cells (S) on either side, separated by a row of fibres; thin-walled fibres (F); thick-walled fibres (TF). Note the pronounced constric­ tion of the ray (R-r) at the point of crossing a row of thick-walled fibres (unlabelled arrow).

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 30 IAWA Bulletin n.s., Vol. 6 (1),1985

, c o

Fig. 5 (above). Libocedrus plumosa bark. - A: Sieve areas on the radial wall in a single file; RLS (SEM) x 1,560. - B: A partly biseriate ray, four cells in height (arrows); TLS (LM) x 250. Note the round shape of ray cells. Axial parenchyma (P). - C: Macerated thin-walled fibre with pointed end (arrow); (LM) x 250. - D: Macerated thick-walled fibre with blunt end (arrow); (LM) x 250.

Fig. 6 (p. 31). Libocedrus plumosa bark. - A; Slit pits (arrows) in the wall of a thin-walled fibre; RLS (SEM) xl ,000. Sieve cell (S). - B: Blind pits (arrows) between a thin-walled (F) and a thick­ walled (TF) fibre; TS (SEM) x 2,400. - C: Crystals (unlabelled arrows) adhering to the radial wall of a thin-walled fibre (in the region of the middle lamella); RLS (SEM) x 2,600. Pits (U). - D:

Downloaded from Brill.com10/01/2021 11:02:14AM via free access IAWA Bulletin n.s., Vol. 6 (1), 1985 31

Thick-walled fibres showing the wall with two main layers: one thin layer on the outside (1) and one thick layer on the inside (2); TS (SEM) x 2,370. Wall of adjacent sieve cells (W). - E: Living periderm showing 3 layers each of phellem (M) and phelloderm (D) and one layer of phellogen (P); RLS (LM) x 270. Note the thin flimsy walls of ph ell em cells. - F: Living phelloderm produced by phellogen derived from ray cells (arrows); RLS (LM) x 130. Note the small size and isodiametric shape of the cells. Thin-walled fibre (F); thick-walled fibre (TF); axial parenchyma (P); ray (R-r); phellem cells (M).

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 32 IAWA Bulletin n.s., Vol. 6 (1),1985

Fig. 7. Libocedrus plumosa bark. - A: Wall of dead axial parenchyma cell (R) showing thickened wall with a few layers; TS (SEM) x 2,750. Dead sieve cell (S). - B: Dead phloem ; TS (LM) x 245. Fibres, both thin- (F) and thick-walled (TF), and sieve cells (S) remain intact; some axial parenchy­ ma cells collapse in the radial direction (P) while others with thickened walls remain intact (Y). - C: Dead sclerified phelloderm cells, showing polylamellate wall (arrows); RLS (SEM) x 875. - D: Dead peridenn showing sclerified phellodenn cells (SC) ; TS (LM) x 30. Unlabelled arrow indicates remnants of phellem cells.

pockets of crystals are pushed outwards by nor­ cies have mostly uniseriate rays. The only dif­ mal growth with the consequence that the crys­ ference is that in L. plumosa, in TS, phloem tals become located in the intercellular spaces. ray cells appear to be constricted at the point She also pointed out that this phenomenon ap­ where a ray crosses a tangential row of fibres , pears to be less common in angiospenns. How­ especially thick-walled fibres. ever, her hypothesis cannot explain the absence Phloem fibres in L. bidwillii and L. plumosa of crystals in the wall of sieve cells and axial pa­ are of two types, thin- and thick-walled. Thick­ renchyma cells in the non-conducting phloem. walled fibres in L. bidwillii are scattered among Sieve areas in L. bidwillii are smaller in dia­ thin-walled fibres, rarely fonning tangential meter (6 - 9 J.LITl) than in L. plumosa (8- 14/lm). rows while in L. plumosa they often form tan­ They are mostly in the radial walls in single gential rows. Most of the fibres in both spe­ files in both species. cies exhibit unusual ends: they are blunt or The heigh ts of phloem rays in L. bidwillii abrupt, rather than pointed as viewed in RLS. and L. plumosa are about the same. Both spe- Fibres with blunt ends were recorded by Chang

Downloaded from Brill.com10/01/2021 11:02:14AM via free access IAWA Bulletin n.s., Vol. 6 (1),1985 33

(1954) in the phloem of Calocedrus decurrens Phelloderm cells in L. plumosa develop into (Torr.) Florin, which was at that time known sclereids just prior to death, probably when a as Libocedrus decurrens Torr. new phellogen is developing further inside the Albuminous or Strasburger cells occur as phloem. In L. bidwillii, the phelloderm cells do erect or upright cells along the margins of not sclerify but collapse markedly in the radial phloem rays and have been described by Chang direction. (1954), Esau (1969) and Howard (1971). Up­ Phellem cells in both New Zealand Libo­ right or erect cells along the margin of phloem cedrus species have very thin flimsy walls. Such rays have not been observed in the present in­ flimsy walls are not found in other gymno­ vestigation. However, this does not exclude the sperms endemic to New Zealand (Chan, 1979, presence of albuminous cells, for they are 1982). known to be distributed among other phloem In both Libocedrus species phellem and tissues (Chang, 1954; Srivastava, 1963; Esau, phelloderm cells derived from axial parenchy­ 1965). According to Evert (1977), the princi­ ma cells appear 4-6-sided in TLS, while those pal feature distinguishing albuminous cells from ray cells are rather isodiametric and smal­ from other phloem parenchymatous cells is ler in size than the former. their connections with sieve cells: pores on the Thus, there are two main distinguishing fea­ sieve cell side and branched plasmodesmata on tures between L. bidwillii and L. plumosa. First­ the albuminous cell side. Such a feature can on­ ly, in the phloem of the former, the thick-walled ly be confirmed by transmission electron mi­ fibres are distributed unevenly among other croscopy, hence a description of albuminous phloem cells. In the phloem of L. plumosa the cells is not included in this work since their thick-walled fibres form tangential rows. presence or absence was not fully certain. In Secondly, all phelloderm cells in the dead peri­ an earlier work (Chan, 1979), the presence of derms of L. plumosa appear sclerified while in upright or erect albuminous cells was mention­ L. bidwillii they are not sclerified and appear ed but it is now questionable if in fact those collapsed in the radial direction. cells were ordinary ray cells that appeared slightly upright. Acknowledgements Trabeculae seem to be very common in the The author wishes to thank Prof. Everett L. phloem of L. bidwillii. The three trees in this Ellis of the School of Forestry and Dr. Brian G. present work carne from the same geographical Butterfield of the Botany Department, Univer­ area in a valley. Neither Patel (1968) nor Meylan sity of Canterbury, Christchurch, New Zealand and Butterfield (1978) have mentioned the oc­ for their advice and encouragement. currence of trabeculae in the xylem of L. bid­ willii. Trabeculae are believed to originate in the vascular cambium where the cell wall mate­ References rial is deposited about a fine filament which Allan, H.H. 1961. Flora of New Zealand. Vol. presumably traverses the living cell (Keith, I. Government Printer, Wellington. 1971). Butterfield and Meylan (1980) suggested Bamber, R.K. 1959. Anatomy of the barks of that trabeculae result from periclinal divisions five species of Callitris Vent. Linn. Soc. in cambial initials or xylem mother cells in N.S.W. 84: 375-381. such a manner that the cell plate fused with a Butterfield, B.G. & B.A. Meylan. 1980. Three­ side wall at some point, producing a rod upon dimensional structure of wood. 2nd Ed. radial expansion. Miiller-Stoll (1965) hypoth­ Chapman & Hall, London. esised that frosts may induce the formation of Chan, L. L. 1979. Bark anatomy of New Zealand trabeculae. This may also be the reason for the Podocarpus species. Diss., B.For.Sc., Univ. abundance of trabeculae in L. bidwillii in this of Canterbury, Christchurch. present investigation since the trees carne from - 1982. The anatomy of the bark of Agathis, a valley. Werker and Baas (1981) suggested that Libocedrus, Dacrydium and Phyllocladus in trabeculae develop due to some disturbance New Zealand. Thesis, M.For.Sc., Univ. of (injury) to the vascular cambium. However, Canterbury, Christchurch. there was no indication of physical injuries in - ,E. L. Ellis & B. G. Butterfield. 1982. A note the bark of Libocedrus. Hence, it is not likely on L- and T-shaped parenchyma cells in the that the formation of trabeculae was due to phloem of Dacrydium cupressinum Lamb. physical injury to the vascular cambium. Since (Podocarpaceae). lAW A Bull. n.s. 3: 177- the trees were collected from the same geo­ 178. graphical areas the formation of trabeculae Chang, Y.P. 1954. Bark structure of North might be genetically linked. More work is need­ American conifers. USDA Techn. Bull. no. ed to support this possibility. 1095.

Downloaded from Brill.com10/01/2021 11:02:14AM via free access 34 IAWA Bulletin n.s., Vol. 6 (1),1985

Craddock, o. 1932a. The rind of the Podocarps Kucera, L.J. & B.G. Butterfield. 1977. Resin with special reference to the bark. Thesis, canals in the bark of Phyllocladus species M.A.Bot., Canterbury College, Univ. of indigenous to New Zealand. New Zeal. J. New Zealand, Christchurch. Bot. IS: 657-663. - 1932b. The rind of the Podocarps with Meylan, B.A. & B.G. Butterfield. 1978. The special reference to the bark. Te Kura Nga­ structure of New Zealand woods. D.S.I.R. here O. New Zeal. School of For.) III (2). Bull. 222, New Zeal. Dept. Sci. & Industr. 61-65. Res., Wellington. Dallimore, W. & A.B. Jackson. 1966. A hand­ Moeller, J. 1882. Anatomie der Baumrinden. book of Coniferae and Ginkgoaceae. Edward Berlin. Arnold, London. Muller-Stoll, W. R. 1965. Dber intrazelluliire Esau, K. 1965. Plant anatomy. 2nd Ed. John Stabbildungen (Trabeculae) im Holz als Wiley & Sons, New York, London, etc. anatomische Eigenhart bei Geholzen expo­ - 1969. The phloem. Handbuch der Pflanzen­ nierter Gebergslagen. Die Kulturpflanze 13: anatomie (Encyclopedia of plant anatomy) 763-799. 5, 2. Borntraeger, Berlin, Stuttgart. Parameswaran, N. & W. Liese. 1979. Crystal­ Evert, R. F. 1977. Phloem structure and histo­ containing walls of spicular cells in Welwit­ chemistry. Ann. Rev. PI. Physiol. 28: 199- schia. IAWA Bull. 1979/4: 87-89. 222. Patel, R.N. 1968. Wood anatomy of Cupressa­ Exley, R.R., B.G. Butterfield & B.A. Meylan. ceae and Araucariaceae indigenous to New 1974. Preparation of wood specimens for Zealand. New Zeal. J. Bot. 6: 9-18. the scanning electron microscope. J. Micro­ Robinson, D.E. & J.K. Grigor. 1963. The origin scopy 101: 21-30. of periderm in some New Zealand plants. - , B.A. Meylan & B.G. Butterfield. 1977. A Trans. Roy. Soc. New Zeal. (Bot.) 2 (9): technique for obtaining clean cut surfaces 121-124. on wood samples prepared for the scanning Society of American Foresters. 1958. Forestry electron microscope. J. Microscopy 110: terminology. 3rd Ed. Soc. Amer. Foresters, 75-78. Washington, D.C. Franceschi, V.R. & H.T. Horner Jr. 1980. Cal­ Srivastava, L. M. 1963. Secondary phloem in the cium oxalate crystals in plants. Bot. Rev. Pinaceae. Univ. Calif. Publ. Bot. 36: 1-142. 46: 361-427. Strasburger, E. 1891. Ueber den Bau und die Howard, E.T. 1971. Bark structure of the South­ Verrichtungen der Leitungsbahnen in den ern Pines. Wood Science 3: 134-148. Pflanzen. Histologische Beitriige Heft III. IA WA Committee on Nomenclature. 1964. Mul­ Gustav Fischer, Jena. tilingual glossary of terms used in wood Werker, E. & P. Baas. 1981. Trabeculae of Sanio anatomy. Konkordia, Winterthur. in secondary tissues of Inula viscosa (L.) Keith, C. T. 1971. Observations on the anatomy Desf. and Salvia fruticosa Mill. lAW A Bull. and fine structure of the trabeculae of n.s. 2: 69-75. Sanio. IAWA Bull. 1971/3: 3-11.

Downloaded from Brill.com10/01/2021 11:02:14AM via free access