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Int. J. Sci. 153(4):589-601. 1992. ? 1992 by The University of Chicago.All rightsreserved. 1058-5893/92/5304-0008$02.00

CUTICLEMICROMORPHOLOGY OFFALCATIFOLIUM DELAUBENFELS ()

RUTH A. STOCKEY,',*HELEN KO,* AND PHILIPPEWOLTZt *Departmentof Botany, University of Alberta,Edmonton, Alberta T6G 2E9, Canada;and tLaboratoirede MorphogeneseVegetale, Universite d'Aix, MarseilleIII, CentreSt. Jerome, France

Cuticle micromorphologyof leaves from all five of the SouthernHemisphere Falcatifoliumde Laubenfels(Podocarpaceae) was studied with scanningelectron microscopy.Both her- bariumand preservedspecimens were examined and showedno differencesin micromorphology.External and internalfeatures of abaxial and adaxial cuticles are characterizedfor the five species and compared to otherknown podocarps. External cuticle surfacesexhibit undulating surfaces that may reflectunderlying epidermal cell outlines, stomatal plugs composed of irregularblocks, and fairly regularstomatal rows. Stomataare separatedby one to three epidermalcells. Two lateralsubsidiary cells are presentwith polar subsidiary cells usually lacking. There is a deep crease in subsidiary cell cuticle, smooth to slightly undulatingcuticle on guardcell surfacesnear the stoma, a ridgeon guardcell cuticle, thin cuticularflanges between guard and subsidiarycells, polar extensions, nonsinuous epidermal cell outlines with cuticle extending to the hypodermis, more elongate epidermal cells between stomatal rows than within rows, and usually granularepidermal cell surfaces. Introduction 1989; Wells and Hill 1989a, 1989b). Leaves of Falcatifolium taxoides (= Dacrydium The genus Falcatifoliumde Laubenfels(Podo- taxoides) carpaceae)contains five species that range from from have been examined using to the Philippines and New Caledonia LM by Greenwood (1987) and by SEM by Stock- (de Laubenfels 1969, 1972; Silba 1986). These ey and Ko (1988), while the four other taxa in are reportedlydioecious or that are this genus have not so far been examined micro- distinguished from the other podocarps by their morphologically.Greenwood (1987) also studied F. sickle-like or falcate, laterally flattened, spirally falciforme (Parlatore) de Laubenfels and F. arranged leaves with twisted bases that spread papuanum de Laubenfels with LM but did not out distichously from the branch (de Laubenfels include detailed descriptions or any illustrations 1969; Silba 1986). The name Falcatifoliumrefers of the cuticle of these taxa. He distinguishedleaves to the basal falcatecurvature of leaves away from of Falcatifolium from those of other podocarps; however, several the branch(de Laubenfels 1969). The genus Fal- cuticularcharacters overlap with catifoliumwas split from DacrydiumSolander ex those of Dacrycarpus(Endl.) de Laub.and Lambert, Florin's (1931) "Gruppe A," by de Gaertner (= Decussocarpusde Laub.). The use- Laubenfels(1969), based on its fertile structures, fulness of SEM and its importance in which are producedon specializedaxillary shoots; have been emphasized in recent years (Wells and a pronounced "hump" on the epimatium that Hill 1989a). Becauseof the complex reliefof many projects laterally from the mature cone; pollen cuticles, SEM has been shown to morphology;and lack of vascularfibers in leaves provide more detail than is possible with the light (Tengner 1965), as well as on general leaf mor- microscope(e.g., Stockeyand Ko 1986; Wells and phology. Hill 1989a). In Cuticularstudies of the Podocarpaceae,while this paper we examine micromorphological numerous, have neglected some of the less ac- featuresof all five currentlyrecognized species of cessible The is a one with Falcatifoliumusing SEM. The micromorphologi- species. family large cal over 170 species (Silba 1986). Leaf structureand similarities are assessed to determine which cuticle morphology at the light microscope (LM) characterscan be used most consistently for tax- level of some specieswere studiedby Florin(1931, onomic purposes. The usefulness of micromor- 1940a, 1940b, 1958), Orr (1944), Buchholz and phological cuticular features in distinguishing these taxa Gray (1948a, 1948b, 1948c), Gray and Buchholz is examined and comparisonsare made (1948, 1951), Townrow (1965, 1967a, 1967b, between these and other known podocarps. 1969), Dilcher (1969), Schoonraadand Van Der Schijff(I974), Ferreet al. (1977), and Greenwood Materialand methods (1987). Scanning electron microscopy (SEM) of Leaves of all species were examined from her- epicuticularwaxes (Morvan 1982, 1987) and leaf barium material (table 1). In addition, preserved morphology of some taxa have been examined specimens of Falcatifolium taxoides were also recently (Stockey and Ko 1988, 1990; Cantrill used. No cuticular differenceswere observed in leaves preserved in FPA (5 mL formaldehyde, 5 ' Author for correspondenceand reprints. mL propionicacid, 90 mL 50%ethanol) and dried Manuscriptreceived January 1991; revisedmanuscript re- herbariumspecimens. ceivedJuly 1992. All leaves were sectioned with the leaf margins 589 590 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Table1

FALCATIFOLIUM DE LAUBENFELS

Material examined Species Typea Herbarium Voucher Source F. angustum de Laubenfels ...... H K E. F. Brunig 5963 Sarawak H K J. A. R. Anderson 2448 Sarawak F. falciforme (Parlatore) de Laubenfels ...... H MO 2728237 P. J. Martin S.37583 Gunong Santubong 1st division, Sara- wak F. gruezoi de Laubenfels ...... H CAHUP Gruezo and Hemaz 27033 Oriental Mindoro, Phillippines F. papuanum de Laubenfels ...... H MO 3058387 K. Kerenga 3 Menyamya, Morobe, F. taxoides (Brongniart et Road to Mt. Dzumac, Grisebach) de Laubenfels ...... H, P UAPC-ALTA McPherson and Stockey Dumbea Valley 3960D New Caledonia

a H = herbarium specimen, P = preserved specimen.

intact, leaving both abaxialand adaxialepidermis All stubs are deposited in the University of attached for cuticle examination. All prepara- Alberta Paleobotanical Collection (UAPC- tions were rehydratedin distilled water for 24 h ALTA). Stomataldistribution was determinedby and then immersed in 20% CrO3 (chromium tri- the examination of leaves from several branches. oxide) solution for 96 h (Alvin and Boulter 1974; Descriptions disregardwhat is obvious debris on Stockey and Ko 1986). Approximately 10 leaves cuticle surfaces.Photographs were taken with the of each species were examined with SEM. Sto- long axis of the leaf parallel to the long axis of matal distributionwas determinedby examining the plate, and stomatalorientations are given with leaves on several brancheswhen specimens were respect to that axis. available. Cuticles were washed in distilled water, air Results dried, and mounted on stubs with silver conduc- tive paint. Both inner and outer surfaces were FALCATIFOLIUMANGUSTUM (FIGS. 1-8) examined by SEM. Specimens were sputtercoat- Adult leaves of this species from Sarawak(table ed with 150 A Au on a Nanotek Sputter Coater 1), are 18-35 mm long by 1-2.5 mm wide (table and examined with a CambridgeStereoscan 250 2). The externalcuticle surfaceis undulatingwith at 20 kV. outlines of underlyingepidermal cells clearlyvis-

Table2 EXTERNALCUTICULAR FEATURES ON LEAVESOF FALCATIFOLIUM

Stomatal Leaf dimensions orientation (length x width to long axis Species in mm)a Florin ring Stomatal plug Stomatal distribution of leaf F. angustum ... 18-35 x 1-2.5 Present Irregular blocks, Discontinuous rows, both Parallel perforate surfaces except on mid- rib F. falciforme .. 20-65 x 5-7 Present/absent on Solid, irregular Discontinuous but extensive Parallel same leaf blocks or rows, both surfaces, ex- sheets cept on midrib F. gruezoi ..... 3.5-20 x 3.5-7 Present/absent on Irregular blocks, Discontinuous rows, both Parallel same leaf or entire stoma surfaces, except on mid- blocked rib F. papuanum 12-17 x 2-3.5 Present/absent on Irregular blocks, Discontinuous rows, both Parallel same leaf granular to surfaces, except on mid- solid rib F. taxoides .... 10-31 x 3-6 Absent/present Solid, irregular Discontinuous but extensive Parallel sunken blocks rows, both surfaces, ex- cept on midrib

a From Silba (1986), and personal observation. I' ~~~~~~~SO-'v

V~

Figs.1-8 Falcatifolium angustum. Fig. 1, Inner surface, reeion of stomatal apparatuswith two subsidiarycells; x 1,500. Fig. 2, Innersurface, stomatal rows, showingtwo and three subsidiarycells per stomatalapparatus; x 310. Fig. 3, Innersurface, stomatal row; x 280. Fig. 4, Inner surface,epidermal cell outlines; x 280. Fig. 5, Outersurface, showing undulating epidermal cell outlines and Florin rings. Several stomata show plugs; x 488. Fig. 6, Inner view, cuticle on guard and subsidiarycell surfaces;x 3,100. Fig. 7, Inner surface,epidermal cell surfacecuticle; x 3,100. Fig. 8, Outer surface,Florin ring surrounding stoma with plug; x 1,600. 592 INTERNATIONAL JOURNAL OF PLANT SCIENCES

Table3

INTERNAL CUTICULAR FEATURES (AM) ON LEAVES OF FALCATIFOLIUM

Epidermal cell dimensions Stomatal (length x width) dimensiong Between Within (polar x stomatal stomatal Species lateral) No. subsidiary cells bands bands Epidermal cell surface F. angustum ... 42 x 38 2 common, 3 occur 91 x 16 37 x 17 Rugose, enlarged pits F. falciforme ... 39 x 36 2 common, 3 occur 67 x 21 12 x 6 Rugose and pitted F. gruezoi 52 x 41 2 common, 3 occur 40 x 13 9 x 8 Pitted usually, to smooth F. papuanum . . 37 x 39 2 common, 3 occur 38 x 13 16 x 10 Smooth to slightly pitted F. taxoides .... 41 x 45 2 common, 3 rare, 4 rare 87 x 14 46 x 17 Rugose and pitted ible (fig. 5). Stomatal plugs are irregular,com- stomatal rows (figs. 2, 3). There are usually one posed of block-like components (table 2) and are or two lateralepidermal cells opposite each lateral often perforatedby channels or free near the edge subsidiary cell (fig. 2). Cuticular flanges on epi- (figs. 5, 8). Prominent upraised Florin rings dermal cells are not sinuous (fig. 4), and irregular (Buchholz and Gray 1948a) surround the sto- flangesoften extend to the hypodermallevel (fig. mata. Rings may be complete or interrupted(fig. 2, upper left). Cuticle on epidermal surfaces is 5) and reflect the underlying pattern of the sto- rugose and pitted (fig. 1; table 3) with extensive matal apparatus. channels into the cuticle sometimes visible (fig. Stomatain discontinuousbut fairlyregular rows 7). are oriented parallel to the leaf axis (figs. 2, 3; table 2). Polar subsidiary cells are often missing FALCATIFOLIUM FALCIFORME (FIGS. 9-22) (table 3; fig. 1). Stomata are situated close to one Adult leaves of this species were collected from anotherusually with one elongate, epidermalcell a coastal area in Sarawak(table 1) from a 4 between them (fig. 2). The presence of this cell is m tall. The external cuticle surface is undulating also noticeable on external cuticle surfaces (fig. with epidermal cell outlines clearly visible (fig. 5). Two subsidiary cells are most common with 1 1). Cuticle on epidermal cell surfaces between three occasionally arising from the division of a stomatal bands often shows a large number of lateral subsidiarycell (fig. 2, top). Cuticle on the small undulations on the surface (figs. 11, 16), subsidiarycells is often rugoseand longitudinally while surroundingepidermal cells have relatively striated (figs. 1, 6). A deep crease or groove is smooth cuticular surfaces (figs. 11, 12, 15). Sto- often seen in this cuticle surface corresponding matal plugs are fairly solid and appearto be com- on the external surfaceto the Florin ring (fig. 1). posed of irregularblocks or sheets (figs. 15, 17; The flangeof cuticle between guardcells is rel- table 2). Prominentupraised Florin ringsare usu- atively thin and slightly rugose(fig. 6). Cuticle on ally seen surroundingthe stoma (figs. 11, 12, 15- guardcell surfacesis smoother toward the stoma 17). Rings may be complete or interrupted(fig. to more rugosetoward the lateral,subsidiary cells 12) and reflect the underlyingpattern of the sto- (fig. 6). A distinct rugose ridge occurs near the matal apparatus. Occasional double rings have lateral edge of the guard cell cuticle. The flange been observed (fig. 16). On some areas of a leaf, between guard and subsidiarycells is slightly ru- Florin rings may be lacking (fig. 13), while they gose, often with an inrolled edge that partially are present on other areas of the same leaf. surrounds the guard cells (figs. 1, 6). Small rib- Stomata are in discontinuous but fairly regular bon-like polar extensions are found but are often rows that are orientedparallel to the leaf axis (figs. broken or curled in preparationsrevealing their 10, 14; table 2). Polar subsidiarycells are lacking delicate nature (fig. 2). (figs. 10, 14, 19, 20), and cell flanges of lateral Epidermalcells surroundingthe subsidiarycells subsidiarycells can be found in contact with one are shorterand often broaderthan those between another (fig. 9). Stomata are situated close to one

Figs.9-22 Falcatifoliumfalciforme.Fig. 9, Inner surface,region of stomatalapparatus with two subsidiarycells and ribbon- like polar extensions(PE); x 1,800. Fig. 10, Innersurface, stomatal rows; x 150. Fig. 11, Outer surface,showing Florin rings, epidermalcell outlines and rugose texture of epidermalcells not in stomatal band; x 165. Fig. 12, Outer surface,Florin ring with modified polar regions reflectingthe underlyingcell structure;x 400. Fig. 13, Outer surfaceof same leaf as in fig. 12, showing lack of Florin rings or slightly depressedrings; x 135. Fig. 14, Inner surface;stomatal bands showing two and three subsidiarycells per stomatal apparatus;x 270. Fig. 15, Outer surface,Florin rings, stomatal plugs, and smooth cuticle texture on epidermalcell between stomata; x 650. Fig. 16, Outersurface, showing double Florin ringand rugoseepidermal cell cuticle outside the stomatalband; x 230. Fig. 17, Outersurface, Florin ringand sheetlikestomatal plug; x 1,350. Fig. 18, Innerview, U'~~~~~~~~~~~~~~~~~~~~~~~~~~F

Si 1

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cuticleon guard cell surface; x 3,600. Fig. 19, Inner surface, stomatal row with subsidiary cellwall flanges incontact; x 650. Fig. 20, Inner surface,region of stomatal apparatus;x 1,700. Fig. 21, Inner view, cuticle on epidermalcell surface; x 1,650. Fig. 22, Inner surface, two stomata sharingtwo subsidiaryrcells. Note encirclingcell at right with cuticle micromorphology similar to its adjacentsubsidiary cell; x 875. 594 INTERNATIONAL JOURNAL OF PLANT SCIENCES another with one to three intervening epidermal rows that are oriented parallelto the long axis of cells (figs. 10, 14). Occasionally closely spaced the leaf (figs. 25, 27; table 2). Polar subsidiary chains of stomata are seen without intervening cells are lacking(figs. 23, 27, 29, 32), and the two epidermal cells (fig. 19). Two subsidiarycells are lateral subsidiarycells may be in contact as in F. most common with three occasionally arising falciforme. Stomatain a row are usually separated from the division of a lateral subsidiarycell (fig. by one to three intervening epidermal cells (figs. 14). One double stomatalapparatus was observed 25, 27, 29, 32). Two subsidiary cells are most with four guardcells sharingtwo subsidiarycells common, with three occasionally arising from a (fig. 22). Furthermore,one of these lateral sub- division of a lateral subsidiarycell (figs. 29, 33). sidiary cells probably divided longitudinally to One double stomatalapparatus was observedwith produce a third cell with cuticular micromor- four guardcells sharingthree subsidiarycells (fig. phologyidentical to that on lateralsubsidiary cells 33). (fig. 22). Cuticle on subsidiarycells is rugose,usu- Cuticle on subsidiary cell surfaces usually ap- ally with a thick outer wall flange with lateral pears as two broad winglike flanges that often undulations (fig. 9). Striations are not common show a thin irregularouter flange (figs. 23, 32). as in F. angustum, but a deep crease or groove This cuticular flange can also be thicker when it is often seen in this cuticle surface(figs. 9, 18, 20, coincides with an epidermal cell wall flange (figs. 22) correspondingto the external Florin ring. 27, 29, 33). Occasionally, lateral undulations of The flangeof cuticle between guardcells is thin this outer flange are seen as in F. falciforme (fig. and relatively smooth (figs. 18, 20). Cuticle on 29). In general,cuticle on subsidiarycell surfaces guard cell surfaces is smooth toward the stoma is smooth to slightly rugose (figs. 23, 33). Stria- and slightly more rugose near the subsidiarycell tions have not been observed as in F. angustum, wall flange (fig. 18). A distinct ridge is present on but a deep crease or groove is present in this the guard cell cuticle with a prominent, inrolled cuticle surface(figs. 23, 27, 29, 32, 33) as in other edge on the flangebetween guard and subsidiary Falcatifolium species. cells (figs. 9, 18, 20). Polar extensions are pro- The flangeof cuticle between guardcells is thin nounced, fairly thick, and often exhibit a central and relatively smooth (figs. 23, 31) as in F. fal- ridge (figs. 9, 18-20). ciforme. Cuticle on guard cell surfacesis smooth Epidermalcells surroundingthe subsidiarycells toward the stoma and slightly more rugose near are shorter,broader, and more irregularin shape the subsidiary cell wall flange (fig. 30). A ridge than those between stomatal rows (fig. 10; table also occurs on the guard cell cuticle surfaceas in 3). If stomatal rows are closely spaced, the inter- other Falcatifolium species (figs. 23, 33) but is vening epidermal cells are broader and shorter not as prominent. The flange between guard and than those between widely spaced rows (fig. 10). subsidiarycells also has an inrolled edge (figs. 23, Cuticularflanges on epidermal cells are not sin- 31), which again is not as prominent as in other uous (figs. 10, 14), and irregularflanges may ex- species. Polar extensions are pronounced with a tend to the hypodermallevel (fig. 14). Cuticle on central ridge (figs. 23, 27, 29, 33) as in F. falci- epidermal cell surfaces is rugose and pitted (fig. channeling as in F. forme. 21) but lacks the extensive Epidermalcells are more irregularin shapethan angustum (fig. 7). in the previously described species but generally FALCATIFOLIUM GRUEZOI (FIGS. 23-33) more elongatebetween stomatal rows and shorter when near the stomatal apparatus (figs. 25, 27; Adult leaves of this species were obtained from table 3). Cuticularflanges on epidermal cells are an isotype specimen from Oriental Mindoro in not sinuous, and irregularflanges may extend to the Philippines (table 1). Externalcuticle surfaces the hypodermal level (figs. 25, 27). Cuticle on are undulating with epidermal cell outlines par- epidermal cell surfaces is pitted (fig. 24) but less tially visible (fig. 28). Cuticle on epidermal cell rugose than F. angustum or F. falciforme. surfacesbetween stomatal bands on some leaves shows a number of small undulations (fig. 28) FALCATIFOLIUMPAPUANUM (FIGS. 34-45) like those in F. falciforme. These, however, are not as pronouncedas in F. falciforme and do not Adult leaves of this species were obtained from occur on all leaves examined (fig. 30). Stomatal a tree 8 m high from Menyamya, Morobe, New plugs are composed of irregularblocks (fig. 26); Guinea (table 1). Externalcuticle surfacesare un- or stomata are also completely blocked with cu- dulating;however, underlyingepidermal cell out- ticle (figs. 28, 30). Prominent Florin rings are lines are not as visible as in other Falcatifolium often seen around stomata and may be complete species (fig. 39). Stomatal plugs are irregularwith or interrupted(figs. 28, 30). They may, however, block-like,granular components (figs. 34, 38, 42). be lackingespecially around plugged stomata (figs. Florin rings are present in some areas of the leaf 28, 30). (figs. 37, 43), while only slightlyraised areas occur Stomata are in closely spaced discontinuous in others (fig. 39). On some leaves the whole area .4i

~~~~~~~~~

Figs.23-33 Falcatifoliumgruezoi. Fig. 23, Inner surface,view of stomatalapparatus with two subsidiarycells, x 1,350. Fig. 24, Innerview, cuticle on epidermalcell surfaces;x 650. Fig. 25, Inner surface,stomatal rows; x 235. Fig. 26, Outer surface, Florin ring and stomatal plug; x 1,025. Fig. 27, Inner surface,stomata with two and three subsidiarycells; x 470. Fig. 28, Outer surfaceshowing epidermalcell outlines, Florin rings, and partialrings around pluggedstomata; x 225. Fig. 29, Inner surface, stomata with two and three subsidiarycells; x 725. Fig. 30, Outer surface, Florin rings, partial rings, and plugged stomata; x 230. Fig. 31, Innersurface, cuticle on guardcell surfaces;x 4,000. Fig. 32, Innersurface, stomatal row with broad subsidiarycell wall flanges; x 700. Fig. 33, Inner surface,stomatal group with four guardcells sharingthree subsidiarycells; x 1,250. OL~t

Figs.34-45 Fakcatifolium papuanum.Fig. 34, Innersurface, region of stomatalapparatus showing three subsidiarycells (SC) and ribbon-likepolar extensions(PE); x 1,800. Fig. 35, Innersurface, stomatal rows; x 175. Fig. 36, Innersurface, epidermal cell outlines; x 230. Fig. 37, Outer surface,Florin ring and stomatalplug; x 1,400. Fig. 38, Inner surface,stomatal band with two and threesubsidiary cells per stomatalapparatus; x 938. Fig. 39, Outersurface, showing stomatal plugs and lack of distinct Florin rings; x 185. Fig. 40, Inner view, cuticle on guardcell surface; x 3,750. Fig. 41, Inner view, cuticle on epidermalcell surface; x 1,000. Fig. 42, Outer surface,stomatal plug morphology;x 5,250. Fig. 43, Outer surface,stomatal row with Florin STOCKEY ET AL.-FALCATIFOLIUM CUTICLE 597

of the stomatalrow is upraisedresulting in a chain The inner sunken ringlike zone corresponds to of Florin rings (fig. 43). the position of the Florin ring in other Falcati- Stomatain discontinuousbut fairlyregular rows folium species and the deep crease in subsidiary are oriented parallel to the long axis of the leaf cell cuticle internally.The outer ring corresponds (fig. 35;table 2). As in other Falcatifoliumspecies to the outer edge of the subsidiarycell wall cuticle polar subsidiary cells are lacking, and as in F. internally (e.g., fig. 46). The leaves observed in falciforme lateralsubsidiary cell wall flangesmay this study show deep creasesin the subsidiarycell be in contact or connected to the polar extension wall cuticle and, therefore, what might be inter- (figs. 34, 38, 44). Stomata are usually separated preted as a partiallysunken Florin ring externally from one another by one to three intervening (fig. 52). epidermal cells. Two subsidiary cells are most Stomatalrows are discontinuous,fairly regular, common, with three rarelybeing the result of the with stomata oriented parallelto the long axis of division of a lateral subsidiary cell (figs. 34, 38, the leaf (figs. 47, 49; table 2). Polar subsidiary 45). One stomatal apparatuswas observed with cells are usually lacking,with two subsidiarycells four guard cells sharing two subsidiarycells (fig. being the most common condition (figs. 47, 49). 45). However, during the present study we found a Cuticle on subsidiary cell surfaces usually ap- few stomata with three or four subsidiary cells pears as two broad flanges, the outer edges of (fig. 51). Stomata are usually separatedby one to which may be thin and, as in F. gruezoi, thicken three intervening epidermal cells (figs. 47, 49). when coincidingwith an epidermalcell wall flange On some parts of a leaf an epidermal cell in the (figs. 34, 38, 44, 45). Cuticle on subsidiary cells terminal position may have the appearanceof a is rugose(figs. 34, 44), sometimes showing lateral polar subsidiary cell, but an intermediate mor- undulations(fig. 38) and horizontalstriations (fig. phology of the cuticle is present (fig. 53). In one 44). A deep crease or groove is usually seen in leaf a pair of stomata are separated by an epi- this cuticle surface (figs. 38, 44) as in other Fal- dermal cell but have adjoining subsidiary cells catifolium species. (fig. 51). One of the stomatal apparati is larger The flangeof cuticle between guardcells is usu- than the other, and the two lateralsubsidiary cells ally thin and relatively smooth (figs. 40, 44). Cu- have divided to produce four, resultingin an un- ticle on guard cell surfaces is smooth to undu- usual morphology for the pair (fig. 51). lating near the stoma and more rugose toward Cuticle on subsidiarycell surfacesis rugoseand subsidiarywall flanges(figs. 34,40,44). A distinct may show longitudinalstriations (figs. 46, 53), as ridge can occur on this cuticle surface (fig. 44) in F. angustum. The outer subsidiary cell wall and a prominent inrolled edge of the flange be- flange is usually very irregular(figs. 46, 51, 53). tween guard and subsidiary cells (fig. 34). Polar A deep crease or groove occurs in this cuticle extensions are pronounced,fairly thick, and often (Stockey and Ko 1988) as in other Falcatifolium exhibit a central ridge (figs. 34, 38, 44, 45). species (figs.46, 53). When these grooves are shal- Epidermal cells surroundingthe stomatal ap- low, a rugose ornamentation can be seen on the paratusare shorterand often broaderthan those subsidiarycell surface(figs. 48, 51). Irregularpeaks between stomatal rows (fig. 35; table 3). Cuticular of cuticle also occur in this region (fig. 51). flanges on epidermal cells are not sinuous (fig. The flangeof cuticle between guardcells is thin 36). Cuticle on epidermal cell surfacesis smooth and relatively smooth to slightly rugose (fig. 48). to slightly rugose (fig. 41); however, pitting or Cuticle on guard cell surfacesis smooth near the have not observed as in other Fal- channels been stoma with slight undulations grading to rugose catifolium species. approachingsubsidiary cells (figs.46,48). A ridge is present on the guard cell cuticle as in other FALCATIFOLIUMTAXOIDES (FIGS. 46-53) Falcatifolium species (figs. 46, 48, 51, 53). The The external cuticle shows slight undulations cuticularflange between guard and subsidiarycells (fig. 52). Stomatal plugs are composed of block- has an inrolled edge (fig. 48). Polar extensions are like components, and upraised Florin rings have delicate, sometimes elongate (fig. 51), with a cen- not been observed (fig. 52). The stomata show tral ridge (figs. 46, 53). three levels of cuticular thickening around the Epidermal cells are distinctly shorter and stomatal apparatus.The stoma is surroundedby broaderwhen in contact with a stomatal row and a ring that is in turn surroundedby a higherlevel more elongate between rows (figs. 47, 49; table ring that may be interruptedat the poles (fig. 52). 3). Cuticular flanges on epidermal cells are not

ringsand raisedcuticle on polar epidermalcells; x 525. Fig. 44, Innersurface, region of stomatalapparatus showing two lateral subsidiarycells; x 150. Fig. 45, Inner surface,stomatal row with four guardcells sharingtwo subsidiarycells and abnormal subsidiarycell divisions on lower stomatal apparatus;x 725. 7 4 4~~~~~~~~~~~~~~~~~~~~~~4

Falcatifoliumtaxoides. Fig. 46, Inner surface,region of the stomatal apparatusshowing two subsidiarycells; 1,400. Fig. 47, Innersurface, stomatal rows; x 150. Fig. 48, Innerview, cuticle on guardand subsidiarycell surfaces;x 3,000. Fig. 49,46-53 Inner surface, stomata with two and threesubsidiary cells; x 270. Fig. 50, Innerview, cuticle on epidermalcell surfaces; Figs.x ,0.Fig. 51, Inner surface,stomatal pair sharingseven subsidiarycells; x 750. Fig. 52, Outer surface,showing sunken Flrnrngs and stomatal plugs; x 550. Fig. 53, Inner surface,stomatal apparatuswith three subsidiarycells and one polar eiemlcell; x 1,750. STOCKEY ET AL.-FALCATIFOLIUM CUTICLE 599 sinuous, and irregularflanges may extend to the channeled in F. taxoides and F. angustum. Cu- hypodermal level (figs. 47, 49, 50). Cuticle on ticle on guard cell surfaces, while generally sim- epidermal cell surfacesis rugose, pitted (fig. 50), ilar, also varies in rugosity, with F. gruezoi, F. and may be channeled as in F. angustum. falciforme, and F. papuanum being generally smoother over all, while F. angustumand F. tax- Discussion oides are more rugose. Externally,epidermal cell undulationsmay be slightlydiagnostic. Many fine With the present study of Falcatifoliumwe are undulations occur on the surfaces of epidermal now able to characterizethe cuticle micromor- cells between stomatal rows in F. falciforme and phology of all five species within the genus. The fewerin F. gruezoi.These undulationsare lacking genus itself is characterized micromorphologi- in the other species. cally by undulatingouter cuticle surfacesthat may The genus Falcatifolium shows many similar- reflectthe underlyingepidermal cell outlines;sto- ities in cuticle micromorphologyto Dacrydium, matal plugs composed of irregularblocks; fairly from which it was originally segregated(de Lau- regularstomatal rows; stomata separatedby one benfels 1969). Stomata, as in most Podocarpa- to three epidermal cells; two lateral subsidiary ceae (Florin 1931; Greenwood 1987), are orient- cells present, with polar subsidiary cells usually ed parallel to the long axis of the leaf; polar lacking; a deep crease in subsidiary cell cuticle; subsidiarycells are absent. There are deep creases smooth to slightly undulating cuticle on guard in subsidiary cell cuticle, and polar extensions cell surfacesnear the stoma; a ridge on guardcell occur (Stockeyand Ko 1990). However, Dacrydi- cuticle;thin cuticularflanges between guardcells; um species so far examined have sinuous epi- rolled cuticular flanges between guard and sub- dermal cell outlines and striationsat the bases of sidiary cells; polar extensions; nonsinuous epi- epidermal cell buttresses (Wells and Hill 1989a; dermal cell outlines with cuticle extending to the Stockey and Ko 1990). Smooth epidermal cell hypodermis; more elongate epidermal cells be- cuticle (Stockeyand Ko 1990) as well as granular tween stomatal rows than within rows; and usu- surfaces (Wells and Hill 1989a) have been re- ally granularepidermal cell surfaces. corded and Florin rings, while lackingin the New The presenceor absence of Florin rings cannot Caledonian species examined (Stockey and Ko be used as a diagnostic feature within the genus 1990), are reported to be present but variable Falcatifoliumsince on one leaf this charactervar- within the genus (Wells and Hill 1989a). ies considerably. Upraised Florin rings do not Among the broad-leavedpodocarpaceous taxa occur in F. taxoides, but sunken rings do occur that may be compared micromorphologicallyto in some cases. In F. falciforme, F. gruezoi, and Falcatifolium, the genus AcmopylePilger has po- F. papuanum they are present on some areas of lar subsidiarycells in greaternumbers and smooth a leaf and absent on others, while in all leaves epidermal cell surface cuticle and lacks Florin examinedofF. angustumthey werepresent. While rings (Stockeyand Ko 1988). Nageia Gaertner(= this feature is consistently present within other Decussocarpusde Laubenfels) have four to six genera of , e.g., Agathis (Page 1980; subsidiary cells, usually with two polar subsid- Stockey and Atkinson 1988), and is diagnostic iaries (Stockey and Ko 1988). The genus Prum- for those genera,this is not so with Falcatifolium. nopitysPhil. shows some similaritiesto Falcatifo- One of the micromorphologicalcharacters that lium, often lacking polar subsidiary cells, but appearsto be most useful for taxonomic purposes subsidiary cell cuticle is quite distinctive with is subsidiarycell cuticle micromorphology.Ver- lateralstriations and a very rugosetexture (Stock- tical striationsappear in F. angustumand F. tax- ey and Ko 1988). oides and horizontal striations in F. papuanum. Imbricate-leavedtaxa were recently described Granularityvaries between the taxa, with F. grue- micromorphologicallyby Wells and Hill (1989a). zoi having the smoothest subsidiarycell wall sur- Dacrycarpus(Endl.) de Laubenfels leaves have face flanges.Thickness and outline of this cuticle stomata parallel to the long axis of the leaf as in appearto be taxonomically significantin the five Falcatifolium;however, these stomata are inter- species. While all taxa show creases or grooves preted as paratetracytic,i.e., with two elongate near the guardcells, only in the New Caledonian lateral subsidiary cells parallel to the guard cells species, F. taxoides, are they shallow enough to and two narrowpolar cells (Dilcher 1974). While reveal peaks of cuticle and a granularornamen- it is difficult to assess the epidermal cell surface tation in the groove. Similar cuticle in this zone morphology from the limited number of photo- was reported in the Araucariaceaein Araucaria graphs presented by Wells and Hill (1989a), it humboldtensisBuchholz (Stockey and Ko 1986), appearsthat at least some of the polar subsidiary also from New Caledonia. cells in Dacrycarpusdacrydioides (Rich.) de Lau- Cuticle on epidermalcell surfacesis smoothest benfels, e.g., have epidermal cell micromorphol- in F. papuanum, then F. gruezoi, slightly more ogy as in Falcatifolium reportedhere. Apparent- granularin F.falciforme, and distinctlypitted and ly, the presence of Florin rings is also variable in 600 INTERNATIONAL JOURNAL OF PLANT SCIENCES this genus (Wells and Hill 1989a). Polar exten- This study, however, utilized only light micros- sions occur in Dacrycarpusthat are very similar copy, and certain cuticular features remain ob- to those reported in Falcatifolium species here. scure using that mode of investigation. The lack From the descriptionpresented by Wells and Hill of polar subsidiary cells reported in the present (1989a), we cannot distinguish this cuticle from study for Falcatifolium is based on the cuticular that of Falcatifolium.An amplificationof the in- micromorphologyof cells in the polar region.The formation on this taxon is required for further epidermalcells in the position of polar subsidiary comparison. cells have a morphology like that on the sur- The generaHalocarpus Quinn, roundingepidermal cells. The same situation oc- Phil., and LagarostrobusQuinn have randomly curs in species of PodocarpusL. Herit. ex Pers. oriented amphicyclic stomata (Wells and Hill (personal observation) and sometimes in Prum- 1989b) and are, thus, quite different than the nopitys (Stockey and Ko 1988) and Dacrydium regularlyoriented stomata of Falcatifolium de- (Stockey and Ko 1990). Thus, the small cells in Hook. ex scribed here. Microcachrys f. Hook., the position of polar subsidiarycells are, in fact, the Tasmanian endemic, does have regular sto- epidermal matal rows but shows irregularlyshaped subsid- cells based on micromorphology. iary cells, many of which are shared by adjacent We hope that studies of extant conifer cuticles stomata, and lacks polar extensions (Wells and at the micromorphologicallevel will serve as the Hill 1989a). Cuticle of MicrostrobosGarden et basis for comparison in future paleobotanical work (e.g., Wells Johnson is similar to that of Microcachryswith and Hill 1989b). Within the Podocarpaceaeand shared subsidiary cells present, and one of the Araucariaceae,cuticle micro- morphology has already proven to be useful in species, Microstrobosfitzgeraldii(F. Muell.) Gard. et Johns. also lacks polar extensions (Wells and the systematic description of several fossil Southern Hill 1989a). Parasitaxusde Laub.,the New Cale- Hemisphere taxa (Cantrill 1989; Wells donian parasitic conifer, has irregularlyshaped and Hill 1989b; Hill and Carpenter1991). Since many extant subsidiary cells, with variable orientation to the podocarpaceous taxa have not yet been guard cells, and shows some similarity to Lepi- described,it is critical that they be well doc- dothamnus (Wells and Hill 1989a). Leaves of all umented for future reference. of these taxa, however, can also be easily sepa- rated from Falcatifolium on the basis of their Acknowledgments external morphology. We thank the following for help in obtaining Fossil leaves of Falcatifolium have been re- specimens: Dr. Peter H. Raven, Missouri Botan- ported from the Miocene of Antarctica (Zas- ical Garden; Dr. Peter Edwards, Royal Botanic tawniak 1981) and the Eocene of Gardens,Kew; Dr. William Gruezo, Herbarium, (Greenwood 1987). The Antarcticmaterial is im- Museum of Natural History, University of the pression materialonly; thus, cuticle has not been Philippines at Los Banos, Laguna.Special thanks described. to Dr. Gordon McPherson, Missouri Botanical Fossil cuticles of Falcatifoliumwere described Garden, for extensive help in the field; George by Greenwood (1987). Falcatifolium australis Braybrook,Department of Entomology, Univer- Greenwood, unlike the extant species, has sinu- sity of Alberta, for technical assistance; and Dr. ous epidermal cell outlines, leaves that are gen- Gar W. Rothwell, Department of Botany, Ohio erallysmaller than living taxa, and stomata most- University for the use of laboratoryfacilities. This ly on the abaxial surface. Greenwood (1987) work was supported in part by Natural Sciences compares F. australis to F. papuanum with re- and Engineering Research Council of Canada spect to stomatal apparatusmorphology and to grant A-6908 and CentralResearch Fund Grant, F. falciforme based on vegetative morphology. University of Alberta to R. A. Stockey.

Literaturecited

Alvin, K. L., and M. C. Boulter. 1974. A controlledmethod Cantrill, D. J. 1989. An Albian coniferous flora from the of comparativestudy of taxodiaceouscuticles. J. Linn. Soc. Otway Basin, Victoria: taxonomy, palaeocology and pa- Bot. 69:277-286. laeoclimatology.Ph.D. diss. University of Melboume. Buchholz, J. T., and N. E. Gray. 1948a. A taxonomic re- de Laubenfels,D. J. 1969. A revision of the Malesianand vision of .I. The sections of the genus and their Pacificrainforest conifers. I. Podocarpaceae,in part.J. Ar- subdivision with special referenceto leaf anatomy. J. Ar- nold Arbor. 50:274-369. nold Arbor. 29:49-63. 1972. Florade la Nouvelle-Caledonieet dependan- 1948b. A taxonomicrevision of Podocarpus.II. The ces. No. 4. Gymnospermes.Musee Nationale d' Histoire American species of Podocarpus:Section Stachycarpus.J. Naturelle,Paris. 167 pp. Arnold Arbor. 29:64-76. Dilcher, D. L. 1969. Podocarpusfrom the Eocene of North 1948c. A taxonomic revision of Podocarpus.IV. America. Science 146:299-301. The American species of Section Eupodocarpus,sub-sec- 1974. Approaches to the identificationof angio- tions C and D. J. Arnold Arbor. 29:123-151. sperm leaf remains. Bot. Rev. 40:1-157. STOCKEY ET AL.-FALCATIFOLIUM CUTICLE 601

Ferre,Y., M. L. Rouane, and P. Woltz. 1977. Systematique Schoonraad,E., and H. P. Van Der Schijff. 1974. Anatomy et anatomie comparee des feuilles de Taxaceae, Podocar- of leaves of the genus Podocarpusin South Africa. Phyto- paceae,Cupressaceae de Nouvelle-Caledonie.Cah. Pac. 20: morphology24:75-85. 241-266. Silba, J. 1986. EncyclopaediaConiferae. Phytologia mem- Florin, R. 1931. Untersuchungenzur Stammesgeschichte oirs, VIII. Moldenke& Moldenke, Corvallis,Ore. der Coniferales und Cordaitales. Kunglica Sven. Veten- Stockey, R. A., and I. J. Atkinson. 1988. Cuticle micro- skapsakademiensHandlingar, Ser. 3, 10:1-588. morphologyof the Araucariaceae:Agathis Salisbury.Am. . 1940a. Die heutige und friuhereVerbreitung der J. Bot. 75:117. KoniferengattungAcmopyle Pilger. Sven. Bot. Tidskr. 34: Stockey,R. A., and H. Ko. 1986. Cuticlemicromorphology 117-140. of Araucariade Jussieu. Bot. Gaz. 147:508-548. * 1940b. The Tertiaryfossil conifers of South Chile * 1988. Cuticlemicromorphology of some New Cale- and their phytogeographicalsignificance. Kunglica Sven. donian podocarps.Bot. Gaz. 149:240-252. VetenskapsakademiensHandlingar, Ser. 3, 19:4-107. * 1990. Cuticle micromorphology of Dacrydium * 1958. Notes on the systematicsof the Podocarpa- (Podocarpaceae)from New Caledonia.Bot. Gaz. 151:138- ceae. Acta Horti Bergiani 17:403-411. 149. Gray,N. E., and J. T. Buchholz. 1948. A taxonomicrevision Tengner,J. 1965. Dacrydium-anatomyand taxonomy.Bot. of Podocarpus.III. The American species of Podocarpus: Not. 118:450-452. Section Polypodiopsis.J. Arnold Arbor. 29:117-122. Townrow,J. A. 1965. Notes on some Tasmanianpines. I. * 1951. A taxonomic revision of Podocarpus.V. The Some lower Tertiarypodocarps. R. Soc. Tasmania Papers South Pacificspecies of Podocarpus:Section Stachycarpus. Proc. 99:87-108. J. Arnold Arbor. 32:82-92. . 1967a. On Rissikia and Mataia podocarpaceous Greenwood, D. R. 1987. Early Tertiary Podocarpaceae: conifersfrom the lower Mesozoic of southernlands. R. Soc. megafossils from the Eocene Angelsea locality, Victoria, Tasmania PapersProc. 101:103-136. Australia.Aust. J. Bot. 35:111-133. 1967b. On a conifer from the Jurassicof East Ant- Hill, R. S., and R. J. Carpenter. 1991. Evolutionof Acmopyle arctica.R. Soc. Tasmania Papers Proc. 101:137-148. and Dacrycarpus(Podocarpaceae) foliage as inferredfrom . 1969. Some lower Mesozoic Podocarpaceaeand macrofossilsin south-easternAustralia. Aust. Syst. Bot. 4: Araucariaceae.Pages 159-184 in GondwanaStratigraphy: 449-479. IUGS Symposium, Mar del Plata, October 1-15, 1967, Morvan,J. 1982. Traitementscomparees des organesfoliar- Unesco, sec. 1 (Biochronologia). es pourl'observation du reliefepicuticulaire au microscope Wells, P. M., and R. S. Hill. 1989a. Leaf morphologyof the electronique a balayage chez Podocarpus macrophyllus imbricate-leavedPodocarpaceae. Aust. Syst. Bot. 2:369- (Thunb.)var. angustifoliusBlume. Bot. Rhedonica,Ser. A, 386. 17:17-24. 1989b. Fossil imbricate-leavedPodocarpaceae from . 1987. Observation au microscope electroniquea Tertiary sediments in Tasmania. Aust. Syst. Bot. 2:387- balayagedes formationscireuses epicuticulaire (feuille-tige- 423. cone femelle)chez Podocarpusmacrophyllus (Thunb.) Don Zastawniak,E. 1981. Tertiaryleaf florafrom the Point Hen- var. angustifoliusBlume Podcarpacees.Flora 179:45-54. nequin Group of King George Island (South Shetland Is- Page, C. N. 1980. Leaf micromorphologyin Agathisand its lands, Antarctica):preliminary report. Stud. Geol. Pol. 72: taxonomic implications.Plant Syst. Evol. 135:71-79. 97-108. Orr, M. Y. 1944. The leaf anatomy of Podocarpus.Trans. Proc. Bot. Soc. Edin. 34:1-54.