CALIFORNIA STATE UNIVERSITY, NORTHRIDGE

THE GRAMMITIDACEAE: ANATOMY OF ADENOPHORUS, XIPHOPTERIS AND GRAMMITIS

A thesis submitted in partial satisfaction of the requirements for the degree of Master of Science in . Biology by Mary Jane Teiman

June, 1981 The Thesis of Mary Jane Teiman is approved:

Dr. Andrew Statrett

Dr. William A. Emhoden

Dr. Kenneth A. Wilson, Chairman

California State University, Northridge

ii DEDICATION

This thesis is dedicated to A.B.T., who never doubted me, or questioned the importance of this work.

It is also affectionately dedicated to the Fern Wizard.

iii ACKNffiiLEDGEMENTS

I am deeply grateful to Dr. Kenneth A. Wilson, my thesis committe chairman, for his friendship, advice and sincere encouragement which not only made this work

possible but enjoyable. I am especially grateful to him for introducing me to comparative plant morphology and to ferns.

I should also like to acknowledge Dr. William A. Emboden for his help and useful suggestions during my work on this project and his constructive criticism of my thesis drafts.

I wish to thank Dr. Andrew Starrett for his careful reading and thoughtful criticism of this manuscript. Thanks are due to my Parents, for their patience, understanding and support throughout my college career. To Jim Thor, a special personal thanks for his patience, his strength, and for his gentle prodding which often kept me going when my spirits got low.

I thank my friends; Susan Crowther, Bill Perry, Betty Rose, Mark Crase, Pam Friedman, Jim Mauch and Joan Parker for their unwaivering moral support.

iv TABLE OF CONTENTS

Page Dedication iii• Acknowledgements iv List of Figures and Tables vi Abstract xi I. Introduction 1 II. Materials and Methods 4 III. AdenoEhorus 6 AdenoEhorus tamariscinus 6 AdenoEhorus haalilioanus 18 AdenoEhorus hymenoEhylloides 28 IV. XiEhOEteris 36 XiEhoEteris serrulata 36 XiEhOEteris trichomanoides 46 v. Grarnmitis 56 Grammitis marginella 56 VI. Discussion 66 Literature Cited 76

v LIST OF FIGURES AND TABLES

Page

Plate I. AdenoEhorus tamariscinus Figure 1. Habit 15 Figure 2. Frond 15 Figure 3. Rhizome scales 15 Figure 4. Cross section of the stele of the rhizome 15 Figure 5. Glandular hairs of rhizome epidermis 15 Figure 6. Cross section of the stele of the petiole 15 Figure 7. Adaxial epidermal surface 15 Figure 8. Abaxial epidermal surface 15 Figure 9. Cross section of lamina 15 Figure 10. Epidermal hairs 15 Figure 11. Paraphysis 15 Figure 12. Cross section of the stele of the root 15 Plate II. Adenophorus tamariscinus Figures 1 - 25. Serial cross sections through the stele of the rhizome 17 Plate III. AdenoEhorus haalilioanus Figure 1. Habit 25 Figure 2. Frond 25 Figure 3. Portion of the frond showing details of the venation 25

vi Page Figure 4. Rhizome scales 25 Figure 5. Cross section of the stele of the rhizome 25 Figure 6. Glandular hair of the rhizome epidermis 25 Figure 7. Cross section of the stele of the petiole 25 Figure 8. Adaxial epidermal cells 25 Figure 9. Abaxial epidermal cells 25 Figure 10. Cross section of the lamina 25 Figure 11. Epidermal hairs 25 Figure 12. Paraphysis 25 Figure 13. Cross section of the stele of the root 25 Plate IV. Adenophorus haalilioanus Figures 1 - 19. Serial cross sections of the stele of the rhizome 27 Plate V. Adenophorus hymenophylloides Figure 1. Habit 33 Figure 2. Fronds 33 Figure 3. Rhizome scales 33 Figure 4. Cross section of the stele of the rhizome 33 Figure 5. Glandular hair of rhizome epidermis 33 Figure 6. Adaxial epidermal cells 33 Figure 7. Abaxial epidermal cells 33

vii Page Plate VI. Adenophorus hymenophylloides Figures 1 - 21. Serial cross sections of the stele of the rhizome 35 Plate VII. Xiphopteris serrulata Figure 1. Habit 43 Figure 2. Frond 43 Figure 3. Portion of the frond showing details of the venation 43 Figure 4. Rhizome scale 43 Figure 5. Cross section of the stele of the rhizome 43 Figure 6. Cross section of the stele of the petiole 43 Figure 7. Adaxial epidermal cells 43 Figure 8. Abaxial epidermal cells 43 Figure 9. Vestigial hydathode on adaxial laminar surface 43 Figure 10. Cross section of the lamina 43 Figure 11. Epidermal hairs 43 Figure 11. Cross section of the stele of the root 43 Plate VIII. Xiphopteris serrulata Figures 1 - 29. Serial cross sections of the stele of the rhizome 45 Plate IX. Xiphopteris trichomanoides Figure 1. Habit 53 Figure 2. Frond 53

viii Page Figure 3. Portion of the frond showing details of the venation 53 Figure 4. Rhizome scale 53 Figure 5. Cross section of the stele of the rhizome 53 Figure 6. Cross section of the stele of the petiole 53 Figure 7. Adaxial epidermal cells, hydathode 53 Figure 8. Abaxial epidermal cells 53 Figure 9. Cross section of the lamina showing vein ending in a hydathode 53 Figure 10. Sclerified epidermal trichome 53 a) origin from abaxial surface b) origin from adaxial surface c) sclerified trichome Figure 11. Epidermal hairs 53 Figure 12. Paraphyses 53 Figure 13. Cross section of the stele of the root 53 Plate X. Xiphopteris trichomanoides Figures 1 - 23. Serial cross sections of the stele of the rhizome 55 Plate XI. Grammitis marginella Figure 1. Habit 63 Figure 2. Fronds 63 Figure 3. Rhizome scales 63 Figure 4. Cross section of the stele of the rhizome 63

ix Page Figure 5. Cross section of the stele of the petiole 63 Figure 6. Adaxial epidermal cells 63 Figure 7. Abaxial epidermal cells 63 Figure 8. Cross section of the lamina 63 Figure 9. Epidermal hairs 63 Figure 10. Cross section of the stele of the root 63 Plate XII. Grammitis marginella Figures 1 - 23. Serial cross sections of the stele of the rhizome 65 Table 1. Comparison of Sporophyte Characteristics known for the Grammitidaceae 73

X ABSTRACT

THE GRAMHITIDACEAE: ANATOMY OF ADENOPHORUS, XIPHOPTERIS AND GRAMMITIS by Mary Jane Teiman Master of Science in Biology

The anatomy of six species of ferns belonging to the family Grammitidaceae was examined using standard paraffin and staining techniques. Adenophorus tamariscinus, Adenophorus haalilioanus and Adenophorus hymenophylloides are endemic Hawaiian species, related anatomically by the presence of glandular paraphyses, glandular rhizome epidermal hairs, concolorous scales, differentiated cortex and solenostelic, dorsiventral rhizomes. Xiphopteris serrulata and Xiphopteris trichomanoides from Jamaica, are characterized by the presence of hydathodes, concolorous scales, and erect, dissected solenostelic rhizomes. Grammitis marginella from Jamaica, noted for its sclerified blade margin, which was found to be superficial in origin

xi was also found to have branched sclerified epidermal hairs, and a dictyostelic rhizome. Branches, which have not been described in the family were found in 5 species; branches are extra-axillary in A. tamariscinus, A. hymenophylloides, X. trichomanoides and G. marginella, and rare and random in stelar organization in X. serrulata. Root propagules known in A. haalilioanus are reported for the first time in X. serrulata. This study represents a significant increase in the number of Grammitid ferns examined for the anatomical characteristics that are important for the determination of phylogenetic trends and for solving of taxonomic problems within the family.

xii I. INIRODUCTION

The fern family Grammitidaceae consists of approxi­ mately 500 species of pantropical distribution. These ferns are primarily small, specialized epiphytes, found in montane cloud forests with low temperatures. Ferns belonging to this family have presented taxo­ nomic problems both in the past and present. Prior to the acceptance of a separate taxonomic category for these ferns, they were frequently classified as members of the comprehensive family Polypodiaceae, but usually with a note about their apparently aberrant characters (Copeland, 1947, for example). Authors still differ in the numbers of genera included in the family (Ching,l940; Holttum,l947, 1949; Copeland,l951). Stokey (1951) feels the gametophytes present strong evidence for the distinction between fern families. The gametophytes of the Grammitidaceae have been extensively studied by Stokey and Atkinson (1958), and are character­ ized by a prolonged and extensive filamentous stage which is distinct in morphology. The filaments are bead-like, with the increase in filament length due to unequal division of the terminal cell. In the Grammitid ferns, there is a strong tendency for these filamentous gamet­ ophytes to propagate vegetatively by fragmentation, where

1 2 the breaking of the filament occurs at modified cross walls. These characteristics are not known for any of the Polypodiaceae, or for any other of the higher ferns (Stokey and Atkinson,l958). Detailed morphological and anatomical studies of the sporophytes of the Grammitidaceae are few. Papers by Nozu (1958-1960) on Micropolypodium, Scleroglossum and Gramrnitis represent some of the earlier work. Wilson and Rickson (1966) described in detail the anatomy of Adenophorus sarmentosus. More recently, Bishop has suggested new revisions of the genera Adenophorus (1974) and Cochlidium (1978) based on morphological and brief anatomical details. In this study, the anatomy of six members of the Grammitidaceae is described. Three species of the endemic Hawaiian fern genus Adenophorus were chosen for study in order to add information needed to determine relationships within this possibly artificial genus (Wilson,l964), as well as for characteristics necessary for family definition. Two groups within the genus have been proposed (Wilson,l9- 64; Bishop,l974). Adenophorus tamariscinus and Adenophorus hymenophylloides are representative of one group, Adenophorus haalilioanus was chosen as representative of the second group. For contrast, three Jamaican Grammitid ferns are included in this study. Two of these species, Xiphopteris serrulata and Xiphopteris trichomanoides were examined for features which may be useful in determining 3

their interrelationship. The third, Grammitis marginella, is one of fourteen species within the family that are characterized by the presence of a sclerified blade margin. II. HATERIALS AND HETHODS

The plant materials used in this study were collected as follows: Adenophorus haalilioanus (Brack.) K. A. Wilson. in Hawaii by Earl T. Ozaki in 1954. Adenophorus hymenophylloides (Kaulf.) Hook.& Grev., at Waianae Iki on the island of Oahu in 1954 by Earl T. Ozaki. Adenophorus tamariscinus Hook. & Grev., in Hawaii in 1954 by Earl T. Ozaki. Grammitis marginella (Sw.) Sw. in St. Thomas Parish, Jamaica by K. A. Wilson 609 and G. Webster, in 1954. Xiphopteris serrulata (Sw.) Kaulf., in Portland Parish, Jamaica by K. A. Wilson 588 and W. Murry in 1954. Xiphopteris trichomanoides (Sw.) Copel., in St. Thomas Parish, Jamaica by K. A. Wilson 608 in 1954. Voucher specimens of the Hawaiian species have been placed in the Herbarium of California State University, Northridge, Northridge, California. Specimens of the Jamaican species are at the Arnold Arboretum, Harvard University, Cambridge, Massachusetts. All Materials were killed and fixed in Formalin-Aceto­ Alcohol (FAA). Materials were prepared for sectioning using standard paraffin techniques (Johansen,l940).

Sections were mad~ using a rotary microtome set for a section thickness of 12 microns. Sections were stained using Conant's Quadruple (Johansen,l940) and mounted.in Diaphane.

4 5

Clearing and bleaching of the whole leaves followed the sodium hydroxide-sodium hypochlorite methods of Brown (19- 58). Leaves were stained in tannic acid and ferric chloride for epidermal features (Wilson,l958a) or in 1% . solution of Safranin in 50% alcohol to distinguish venation patterns. Scales were peeled from the rhizome, dehydrated in ethyl alcohol and mounted in Diaphane. All figures were drawn using a microprojector. III. ADENOPHORUS

Adenophorus tamariscinus The rhizome of Adenophorus tamariscinus is prostrate. to ascending, occasionally branched, one or more centimeters long and 5 to 7 mm thick. The rhizome exhibits a dorsi­ ventral organization; fronds are borne in 2 ranks on the dorsal surface (Pl.I,fig.l). Associated with each petiole is a branch bud, which is extra-axillary in position, and directed laterally. The roots are predominantly ventral, wiry and highly branched. The rhizome is thickly covered with lanceolate to narrowly triangular concolorous scales which are 1 to 3 mm long, terminated by a single clavate glandular cell, and are rounded to cordate at the base (Pl.I,fig.3). The fronds are highly variable (Pl.I,figs.l,2). Fronds are 4 to 15 em in length, the winged petiole measuring 1/6 to l/3 of the total length. Blades are deeply bipinnatifid and are ovate, elliptic to obovate in outline. Pinnae al­ ternate along the rachis, are triangular to ovate in out­ line and 4 to 15 mm long. Pinnae are reduced in size and number of divisions at the base and the tip of the frond. The pinnules alternate and may overlap or be widely spaced. Pinnules are 1 to 3 mm long, linear-spatulate, with an acute to rounded apex; fertile pinnules are usually slightly broader with a rounded. to obtuse apex.

6 7 first pinnule is acroscopic and is frequently pinnatifid, more distal pinnules are rarely pinnatifid. Venation is pinnate; one midline vein in each pinnule, with exception of the pinnatifid pinnules where the vein branches to each lobe. Veins do not extend to the blade margin (Pl.I,fig. 2). The outline of the stem varies from circular to ellip­ tical in cross section. The vascular cylinder is organized as a solenostele with non-overlapping leaf gaps. Extra­ axillary branch buds occur associated with each leaf trace. These buds may develop into branches, or more frequently remain dormant. The leaf trace is divided into 2 separate vascular strands with the branch trace originating in between the leaf trace strands. In Adenophorus tamariscinus it is difficult to determine if the branch trace is primarily associated with the main axis or the leaf trace itself, since both configurations are observed (Pl.II.). The branch trace clearly separates from the main axis prior to the paired leaf trace in some instances (Pl.II,figs.2-6). However, in other instances the branch trace is more closely associated with the leaf traces (Pl.II,figs.l6-21). Single roots are generally associated with the.forma­ tion of each leaf gap; in most instances, the root trace is seen opposite the gap (Pl.II,figs.3-5,14-15). ·single root traces are also observed to depart from the main axis 8

in regions between sucessive leaf gaps (Pl.II,figs. 11,23, 24). Pairs of roots were rarely seen and then only in po­ sitions not related to leaf gap formation. Most frequently the root traces exit the stem quickly and directly. Occa­ sionally root traces are seen to continue for several internodes within the cortex and parallel to the stele before exiting the stem. The stele of the rhizome is circular in cross section. The large central parenchymatous pith consists of approxi­ mately 80 to 100 irregular cells. The inner phloem is from 1 to 3 layered and is separated in most cases from the xylem by a single layer of parenchyma cells (Pl.I,fig.4). The xylem cylinder is from 1 to 4 cells thick, the tra­

cheids are of relatively uniform size. A layer of p~ren­ chyma separates the external phloem from the xylem. The external phloem is 1 to 2 layers thick, the cells are smaller and more rectangular than the internal phloem elements; the external phloem elements being 1/4 to l/2 the width of the internal phloem cells. The pericycle lies outside of the external phloem, and is composed of 1 to 3 layers of cells. The stele is bounded by an endodermis composed of rectangular, nucleated cells with bright staining casparian strips on their radial walls. The cortex is 11 to 13 layers thick. The inner 7 to 8 9

cortical layers consist of heavily thickened sclerenchyma cells with obvious pits, these cells are often completely occluded in the areas surrounding leaf and root traces. The outer 4 to 5 cortical cell layers are non-uniform in size of shape. Plastids are visible scattered throughout the cells of the cortex. The cells of the single layered epidermis are thin walled, and not greatly different in size or shape from the cells of the outer cortex. Epi­ dermal cells bear scales (Pl.I,fig.3) and club shaped glandular hairs (Pl.I,fig.S). Occasionally within the parenchymatous pith short accessory vascular tracts can be seen. These vascular tissues begin and end blindly. Sometimes the tracts are represented by strands of tracheids, 3 to 7 cells in dia­ meter. However; in one instance a strand of xylem with a complete ring of phloem surrounding and separated from the xylem by a layer of parenchyma, is seen to continue for a distance of more than 4 internodes. These accessory vascular tracts were found in the oldest portions of the stem. The branches formed from the extra-axillary buds are solenostelic in their vascularization. Two separate vascular strands enter the base of the petiole. Each xylem band has a pronounced protoxylem pole forming the adaxial end. A single layer of parenchyma separates each xylem band from its surrounding ring of phloem. The phloem is 10

1 to 5 elements wide, and surrounds each band of xylem except at the tip of the grouped protoxylem tracheids. The 2 strands of vascular tissue are separated by large par­ enchyma cells identical in size and continuous with the parenchyma forming the 1 to 3 layered pericycle. The trace is surrounded by the endodermal sheath composed of rectangular, nucleated cells displaying casparian strips on their radial walls. Immediately, the phloem rings fuse along the midline of the leaf trace, forming a continuous central portion of phloem 5 to 10 elements wide, in between the xylem bands (Pl.I,fig.6). At this point, the cortex is composed of 10 to 14 layers of cells. The inner cortex of 5 to 7 rows of cells is heavily sclerified to totally occluded. The outer 5 to 7 rows of the cortex is composed of cells with slight sclerification decreasing to no sclerification in the outer most layers. The epidermal cells are thin walled and of similar size as the outer cortical cells, and bear glandular hairs similar to those of the rhizome epidermis and a few scales. Progressing acropetally, each xylem band takes on a more regular L shape, with the protoxylem forming the small lateral arms. As the strands begin to merge, first the central phloem is lost and only 1 or 2 rows of small parenchyma separate the metaxylem tracheids of each band. At this level small sub-adaxial ridges can be seen forming 11

in the epidermis, these increase in size acropetally into the wings of the petiole. Two to 3 mm from the base of the petiole the xylem bands fuse at the center of their lengths forming a roughly X shaped xylem core. Continuing acropetally, the abaxial arms of the X shaped xylem condense toward the midline resulting in a roughly triangular shaped xylem core. Both adaxial and abaxial laminar surfaces are charac­ terized by the presence of numerous distally directed glandular hairs (Pl.I, figs.7,8). These trichomes may be sessile or on a 1 or 2 celled stalk and are frequently branched (Pl.I,fig.lO). The direction of these hairs appears to be imposed by adjacent swollen epidermal cells, swollen epidermal cells also appear in areas non-adjacent to the hairs resulting in a pappillate surface (Pl.I,fig. 9). Adaxial epidermal cells are irregular in face view, 2 to 4 times longer than wide, with coarsely wavy cell walls (Pl.I,fig.7). Epidermal cells superficial to the veins do not differ greatly in size or shape from the other epidermal cells. Stomata are restricted to the abaxial surface, are randomly scattered and slightly raised in relation to the surrounding epidermis (Pl.I,fig.9). Abaxial epidermal cells are more irregular in shape, with more sharply 12

undulate walls than those of the adaxial surface (Pl.!, fig.8). Abaxial epidermal cells superficial to the veins are more rectangular in shape than adjacent epidermal cells. The most conspicuous feature of the lamina cross section is the irregular size of the epidermal cells (Pl. I,fig.9). The mesophyll is composed of small irregular, loosely arranged parenchyma with small intercellular spaces; except the substomatal chamber, which is consid­ erably larger. Veins are closer to the abaxial surface. Round sori are borne on raised, dome shaped recep­ tacles that are terminal on punctiform fertile veins. Sporangial development is of the mixed type. The sporangia have 11 to 13 thickened cells in the annulus and a single row of cells at the base of the stalk. With the sporangia are numerous large glandular paraphyses (Pl.I,fig.ll). Terminated by a massive glandular cell, the stalk of the paraphysis is a uniseriate row of 4 to 6 cells. The glandular tips of the paraphyses are bent over the sporan­ gia forming a protective mat. The roots have a diarch stele, the 2 opposite proto­ xylem poles consist of 2 to 4 tracheids each (Pl.I,fig.l2). A single layered phloem surrounds the xylem band except at the protoxylem poles. A single layer of small parenchyma cells separate the phloem from the metaxylem tracheids. The pericycle is composed of narrow, elongated cells. 13

The inner cortex consists of 2 to 5 layers of heavily sclerified cells occluded with a densely staining material. The ring of sclerified cortical cells is uneven, with thinner areas in the regions of the protoxylem poles. The outer 3 to 4 rows of cortical cells have only slightly thickened walls and are larger in diameter than the inner cortical cells, and are frequently filled with plastids. Epidermal cells are lightly sclerified on the inner and radial walls and are larger than the cells of the outer cortex. The epidermal cells frequently bear persistant, non-septate, sclerified root hairs. 9 . 14

PLATE I AdenoEhorus tamariscinus Figure 1. Habit. Figure 2. Frond. Figure 3. Rhizome scales. Figure 4. Cross section of the stele of the rhizome. Figure 5. Glandular hairs of the rhizome epidermis. Figure 6. Cross section of the stele of the petiole. Figure 7. Adaxial epidermal cells. Figure 8. Abaxial epidermal cells. Figure 9. Cross section of the lamina. Figure 10. Epidermal hairs. Figure 11. Paraphysis. Figure 12. Cross section of the stele of the root. The scale indication at each figure is in millimeters. 15 16

PLATE II Adenophorus tamariscinus Figures 1 - 25. Selected serial cross sections of the stele of the rhizome showing the origin of leaf traces, branch traces, and root traces. The scale indication is in millimeters. 17 18

Adenophorus haalilioanus The rhizome of Adenophorus haalilioanus is erect, usually less than 1 em in length, 2 to 3 mm thick with a heavy investiture of roots and linear concolorous scales (Pl.III,fig.l). The scales are approximately 2 mm long, with a subcordate to reniform base and apically terminated by a minute gland (Pl.III,fig.4). The roots are slender, few branched, and bear propagules from which new plants develop. Petioles are short, usually less than 2 mm long, rounded to winged and crowded upon the stem. The blades are linear, 2 to 5 em long, 4 to 7 mm wide, pinnately crenate to cleft with rounded to slightly angular lobes, an obtuse to rounded apex and attenuate base (Pl.III,fig. 2). Venation is pinnate; the veins are few forked with occasional vein anastomosis occuring within the larger lobes. All veins end before the leaf margin (Pl.III,fig. 3). The rhizome is circular to elliptical in cross section. The vascular cylinder is initially protostelic, gradually becoming solenostelic as the stem gets older. During the transition from the protostele, scattered parenchyma cells may be noted among the tracheids. The xylem cylinder is interrupted by leaf gaps during this medullated stage. Later, the parenchyma cells coalesce to form a permanent 19 I '

pith. A central strand of phloem develops within the pith in later stages (Pl.IV,figs.l-3). The stele exhibits dorsiventral organization in regards to leaf trace origin, even though externally the dorsiventral nature is not evident (Pl.III,fig.l; Pl.IV, figs.l-19). The first leaf trace results in a long leaf gap with subsequent leaves borne alternately from the edges of the gap (Pl.IV.). This dorsal gap will close irregular­ ly, with the next leaf forming a subsequent gap at a similar position. Two root traces are associated with the gap forming leaf trace; these root traces emerge at right angles to the leaf trace and opposite each other (Pl.IV, figs.S-6). A single root trace emerges opposite the leaf traces which depart from the sides of the long dorsal gap (Pl.IV,fig.l0,14,18). The small central pith is composed of a few large parenchyma cells. Internal phloem consists of uniform round cells grouped centrally in the pith. The xylem cylinder is from 1 to 3 tracheids thick. External phloem is composed of narrower, more elongated cells, which are less than 1/2 the width of the internal phloem elements and slightly longer. External phloem is 1 to 2 layers thick, and is irregularly separated from the xylem by bands of small parenchyma cells (Pl.III,fig.S). The pericycle is 1 to 2 cells thick, these parenchyma cells are greater in diameter than any others seen elsewhere in 20

the stele. The endodermis consists of many small cells displaying bright staining casparian strips. The cortex is 7 to 10 cell layers thick. The inner 2 to 5 cortical rows form a distinctive layer of heavily sclerified cells, many are entirely occluded, the exception being small areas of thick walled, protoplast containing cells frequently seen opposite a departing leaf trace. The sclerenchyma layer surrounds traces leaving the stele and is continuous with the sclerenchyma of the petiole and root. Outer cortical cells are thinner walled than the inner layers; many of the cells contain large nuclei and numerous plastids. Cells of the single layered epidermis are not greatly different in size from those of the outer cortex. Epidermal cells bear numerous scales and club­ shaped glandular hairs (Pl.III,fig.6). The leaf trace is U or V shaped in origin, but becomes rounded as it enters the petiole. At the base of the pe­ tiole the xylem is round in cross section, the protoxylem tracheids forming the adaxial edge of the cylinder (Pl.III, fig.7). A single to double layered phloem forms an incom­ plete circle around the xylem, and is separated from the xylem irregularly by parenchyma. The pericycle is 1 to 2 layered. Endodermal cells are narrow and rectangular. The inner cortex is composed of 4 to 5 rows of heavily sclerified cells which are usually occluded with dense staining material. The outer 1 to 3 cortical layers are 21

composed of thinner walled nucleated parenchyma cells. The epidermis is not distinct from the outer cortical cells at this level. Petiole bases are frequently clothed in scales. Slightly further up the petiole, as marginal epidermal wings become evident in cross section, the xylem cylinder changes in outline becoming more oval to reniform with the protoxylem tracheids forming 2 adaxially directed poles. Epidermal cells change in appearance, becoming larger in diameter and appearing more like those of the leaf blade, with enlarged cells forming the lateral ridges that are continuous with the blade margins. Adaxial epidermal cells are approximately oval in shape, 1 to 1 l/2 times longer than wide with moderately wavy longitudinal walls (Pl.III,fig.8). Epidermal cells superficial to lateral veins are not different than those of the intercostal areas; and those cells over the·main vein are only slightly more rectangular than the latter. The abaxial laminar surface is characterized by the presence of irregularly placed stomata and epidermal cells that are larger than those of the adaxial surface, more rectangular, with highly irregular undulate longitudinal walls (Pl.III,fig.9). Abaxial epidermal cells are 3 to 4 times longer than wide. Only the epidermal cells super­ ficial to the main vein differ at all in size and shape, 22

these being smaller and more evenly rectangular. In cross section, the upper epidermis displays pro­ jecting arms that extend into the mesophyll. The cells of the lower epidermis also have these projections, but less regularly. The cuticle of the upper epidermis is twice the thickness of the cuticle on the lower epidermis. The mesophyll consists of irregularly armed parenchyma sepa­ rated by large intercellular spaces (Pl.III,fig.lO). The primary vein is surrounded by a layer or two of occluded sclerified cells, secondary veins usually lack the sclerified ring. Epidermal hairs are scattered near the primary vein, and occur more frequently on the abaxial surface than on the adaxial surface. These hairs may be simple, uniseriate 2 to 3 cells long; or once to twice branched and composed of 5 to 8 cells. Hairs are terminated by large glandular cells and originate from small round epidermal cells (Pl. III,fig.ll). Oval to circular sori are borne on a flattened receptacle. The fertile vein may simply be an expanded portion of a tertiary vein, where the sori are not terminal or may be a short basiscopic branch from a tertiary vein where the entire branch is fertile (Pl.III,fig.3). Sporangial development is of the mixed type. Sporangia have an annulus of 10 to 12 (mostly 11) thickened bow cells and a single row of cells forming the base of the stalk. 23

Mixed with the sporangia are numerous uniseriate paraphyses with glandular terminal cells (Pl.III, fig.l2). The roots are diarch, with 2 protoxylem poles on opposite ends of the lens shaped xylem cylinder. The single layered phloem surrounds the xylem except at the protoxylem poles, and is separated from the xylem by a few scattered small parenchyma cells. Surrounding the vascular tissues is a single layered pericycle of large thin walled cells (Pl.III,fig. 3). The endodermis is composed of thin walled cells that are frequently broken during the preparation of the roots for sectioning. The inner 1 to 4 layers of the cortex consists of sclerified cells that are usually occluded with a dense material. Opposite the protoxylem poles, the sclerified cortex is less wide than in other areas, so that the combined lens shape of the stele and the sclerified corti­ cal cells results in an almost perfectly circular area. The outer cortex is composed of 3 to 4 layers of lightly sclerified cells that are larger in diameter than the inner cortical cells. Many of the cortical cells immediately subtending the epidermis are densely filled with plastids. The epidermis consists of rectangular cells with thickened inner and radial walls. Frequently, the epidermal cells bear persistant, sclerified, non­ septate root hairs. 24

PLATE III AdenoEhorus haalilioanus Figure 1. Habit. Figure 2. Frond. Figure 3. Portion of frond showing details of venation. Figure 4. Rhizome scales. Figure 5. Cross section of the stele of the rhizome. Figure 6. Glandular hair of the rhizome epidermis. Figure 7. Cross section of the stele of the petiole. Figure 8. Adaxial epidermal cells. Figure 9. Abaxial epidermal cells. Figure 10. Cross section of the lamina. Figure 11. Epidermal hairs. Figure 12. Cross section of the stele of the root. The scale indication at each figure is in millimeters. 25 26

PLATE IV Adenophorus haalilioanus Figures 1 - 19. Selected serial cross sections of the stele of the rhizome showing the origin of leaf traces and root traces. The scale indication is in millimeters. 27

@@1 2

5

8 ~ ~

11

12 13

16

18 I I I I 10.2 28

Adenophorus hymenophylloides The rhizome of Adenophorus hymenophylloides is pros­ trate, usually less than 1 em in length and 3 to 4 mm thick. Branches are seen infrequently, and are much weaker and smaller than the main axis. Pendulous fronds are borne on the dorsal surface; the wiry, few branched roots from the ventral or lateral sides (Pl.V,fig.l). The rhizome is clothed with linear-lanceolate concolorous scales, 1 to 2 mm long with an apical clavate gland and a blunt to rounded base (Pl.V,fig.3). The bipinnatifid, linear-lanceolate fronds are 2 to 8 em long, the petioles comprising l/5 or less of the total length (Pl.V,figs.l,2). The petiole and rachis are clothed in apically directed appressed glandular hairs. Pinnae are 2 to 5 mm long, linear to elliptic, spreading or con­ gested along the rachis, and simple to five-cleft. Pinnae freely disarticulate from the rachis. Pinnules are 1 to 3 mm long, elliptic to spatulate with rounded to acute apicies. Pinnules are frequently only represented by shallow lobes (Pl.V,fig.2). In the material studied, which is from Oahu, pinnules were developed only on the aero­ scopic side of the pinnae. According to Bishop (1974) this is a strong tendency of this particular population and does not reflect the species throughout its distribution. Venation is pinnate, one vein entering each pinnule, ending freely in the mesophyll before reaching the margin. 29

The rhizome is circular to elliptical in cross section. The vascular cylinder of A. hymenophylloides is soleno­ stelic with long dorsal leaf gaps with numerous leaf traces attached to the sides of the gap (Pl.VI). The origin of successive leaf traces alternates from side to side of the common gap. This dorsal gap irregularly closes (Pl.VI, figs. 1,21). Extra-axillary branch buds develop in association with most of the leaf traces (Pl.VI,figs.S-6,8,18). Branch traces are separated abruptly and depart from the vascular cylinder immediately; the single U or V shaped leaf traces are somewhat slower to leave the rhizome vascular cylinder. Branch traces are small and do not appear to contribute to dorsal gap formation which may explain the weak nature of the branches as compared to the main axis (Pl.VI,figs.6, 8,18). Roots arising below the juncture of the leaf trace and stelar gap were either at right angles (Pl.VI,figs.2-3) or opposite (Pl.VI,figs.S-7). Roots occuring after the gap formation were usually at right angles to the gap (Pl.VI, figs.l0,16). Pairs of roots originate opposite one another (Pl.VI,figs.20-21). The stele is circular to oval in cross section, with a small pith consisting of 10 to 20 parenchyma cells. The internal phloem is 1 to 2 layered and is separated from the xylem by a single row of parenchyma in most areas. 30

The xylem cylinder is 1 to 3 tracheids thick, and composed of non-uniform cells. The external phloem is 1 to 2 layers wide and is irregularly separated from the xylem by parenchyma. The pericycle is 2 to 3 layers thick (Pl. V,· fig.4). Endodermal cells were all destroyed, and the en­ tire stele pulled away from the cortex due to the killing and fixing agent and the drying out of the material during storage prior to this study. The cortex is composed of 5 to 7 layers of cells, the inner 2 layers consist of only slightly thickened cells in contrast to the heavily sclerified walls seen in the same region of A. tamariscinus. Only regions directly sur­ rounding exiting leaf and root traces show heavy sclerification of the walls and occasional occlusion of the lumen. The outer 3 or 4 cortical layers are thinner walled and composed of uniformly sized cells. Epidermal cells differ from the cortical cells in being larger in diameter, and bearing numerous clavate glandular hairs (Pl.V,fig.S), and scales (Pl.V,fig.3). Both epidermal surfaces of the frond are densely covered with sessile glandular trichomes (Pl.V,figs.6,7), that are borne on small round epidermal cells. The adaxial surface is characterized by sharply undulate cells of irregular size and shape (Pl.V,fig.6). The abaxial surface is composed of more wavy irregular cells and sunken stomata (Pl.V,fig.7). 31

Further information on the anatomy of Adenophorus hymenophylloides is sparse due to pecularities in the treatment of the collected material. Specimens were killed and fixed in FAA, then later dehydrated and stored dry, then rehydrated in FAA. This treatment left most tissues collapsed making the study of the petiole and root tissues impossible and causing a collapse of the leaf mesophyll making cross sections of the leaf unintelligible. No fertile material was left undamaged. Certainly more work is necessary to complete the study of the anatomy of this species. 32

PLATE V AdenoEhorus hymenoEhylloides Figure 1. Habit. Figure 2. Fronds. Figure 3. Rhizome scales. Figure 4. Cross section of the stele of the rhizome. Figure 5. Glandular hair of the rhizome epidermis. Figure 6. Adaxial epidermal cells. Figure 7. Abaxial epidermal cells. The scale indication at each figure is in millimeters. 33 34 , '

PLATE VI Adenophorus hymenophylloides Figures 1 - 21. Selected serial cross section of the stele of the rhizome showing the origin of leaf traces, branch traces, and root traces. The scale indication is in millimeters. 35 IV. XIPHOPTERIS

Xiphopteris serrulata The rhizome of Xiphopteris serrulata is erect, infrequently branched, usually less than 3 em in length and 1 to 2 mm thick (Pl.VII,fig.l). The stem is covered with light brown, concolorous, peltate, linear-lanceolate scales 2 to 2.5 mm long. Scales are terminated by a glandular cell at the end of a uniseriate stalk which is 1 to 3 cells in length (Pl.VII,fig.4). Roots are wiry, dark brown and highly branched. Rarely, the roots bear propagules which develop into new plants. Petioles are short, less than 3 mm long, naked, and spiral off the stem. Leaf blades are simple, linear, and pinnately serrulate (Pl.VII,fig.2). Sterile fronds are usually shorter than the fertile fronds, being 1 to 1.5 em in length and 2 mm broad. Fertile blades range in length from 3 to 7 em, the conduplicately folded fertile tip being from less than 1/4 to greater than l/2 the total frond length. The fertile portion of the blade is entire to slightly sinnuate, the lower sterile portion is similar in margin to the sterile fronds. Venation is pinnate, free and unbranched. Veins in the fertile portion of the frond stop scarcely short of the margin, sterile veins end more distant from the margin (Pl.VII,fig.3). The rhizome is circular to oval in cross section.

36 37

Initially the stem is protostelic. A succession of leaves with short internodes results in a stelar organization consisting of 2 to 3 vascular strands within a single endodermis. Each vascular bundle consists of a circular to crescent shaped xylem band, 1 to 3 tracheids wide surrounded first by a layer of parenchyma cells and then by a single layer of small phloem cells. Phloem may form an entire ring about the xylem, or be broken up by patches of parenchyma. The vascular bundles surround a small parenchymatous pith of 10 to 15 cells, and are in turn surrounded by a 1 or 2 layered pericycle and the endodermis which is composed of narrow elongated cells (Pl.VII, fig. 5). The cortex is composed of 5 to 6 rows of sclerified cells, that are most frequently occluded. The epidermis consists of large nucleated cells, distinct from the cortical cells, and irregularly subtended by a row of small hypodermal cells. Leaf traces remain in the cortex for a considerable distance, however; roots exit quickly and horizonally. Vascular bundles frequently separate to form separate meristeles, each vascular bundle surrounded by its own endodermis. Highly sclerified cortical cells fill all areas surrounding the meristeles, a parenchymatous pith is lacking. This vascular bundle separation may or may not be associated with the formation of a new leaf gap. These meristeles frequently rejoin, the vascular bundles 38

retaining their own identity (Pl.VIII,figs.22-26), or the vascular bundles fusing then opening again with the next leaf gap (Pl.VIII,fig.l0-14). In regions of slightly longer internodal length, the vascular bundles fuse to form a more typical solenostele interrupted by leaf gaps (Pl.VIII,fig.9-12). The 1 to 3 tracheid wide xylem is surrounded by a single layer of phloem internally and externally and separated from the phloem by a single layer of small parenchyma cells. A small central pith is surrounded by the vascular tissues, and the latter are encircled by a parenchymatous pericycle and a single endodermis. Root traces appear to bear little organizational relationship with one another; they arise during the inter­ nodes but not at any position fixed by the previous or successive leaf gap (Pl.VIII,figs.7,18). Branch traces are not associated with the leaf trace, but are infrequent and random in occurance (Pl.VIII,figs.21-22). Most often the branches are in a state of arrested development; in cross section the tissues appear meristematic with a triangular apical cell buried in the center of the bud. Externally, the arrested branches appear as small knobs seen only when the scales are removed from the area. A small single trace enters the petiole. The stele, which is bounded by small flattened endodermal cells, is almost perfectly circular in cross section. Xylem occupies 39

the center of the stele, and consists of 2 to 3 proto­ xylem tracheids adaxially, and 1 or 2 metaxylem tracheids abaxially (Pl.VII,fig.6). Pholem surrounds the xylem except at the protoxylem pole. The pericycle is single layered. The cortex is 4 to 6 layers wide and consists of heavily sclerified cells occluded with densely staining material. The epidermis is distinct, composed of large thick walled cells. Further up the petiole a hypodermal layer becomes apparent, these cells are smaller in size than the epidermal and cortical cells, and are not sclerified. In cross section the petiole is circular. The adaxial surface of the frond consists of sharply undulate cells, that are 2 to 4 times longer than wide. Epidermal cells superficial to the primary vein are rec­ tangular with smoothly wavy side walls and flat to slightly curved end walls. Epidermal cells superficial to the secondary veins do not greatly differ from those of the intercostal epidermis (Pl.VII,fig.7). The adaxial surface has small vestigial hydathodes involving only 4 to 8 epidermal cells (Pl.VII,fig.9). The position of the vestigial hydathode is not terminal to the vein; the vein ends blindly in the mesophyll at points slightly beyond the hydathode. These vestigial hydathodes are also seen near the ends of the fertile veins. Epidermal cells of the abaxial surface are larger, more irregular than those of the adaxial surface; and have more 40

rounded finger-like projections composing the undulate cell walls (Pl.VII,fig.8). Abaxial epidermal cells super­ ficial to the secondary veins are slightly more regular in shape than those of the intercostal areas. Stomata are restricted to the abaxial laminar surface. Small clavate trichomes are sparsely distributed along the primary vein on both adaxial and abaxial surfaces. These trichomes arise from small round epidermal cells; are usually 2 celled, the terminal cell being swollen and glandular (Pl.VII,fig.ll). In cross section, the adaxial epidermal cells are seen to have a thick cuticle and round vertical projections into the mesophyll. Abaxial epidermal cells also display these projections but to a lesser extent, and also have a thinner cuticle. The mesophyll is composed of irregular spongy parenchyma cells with numerous small intercellular spaces (Pl.VII,fig.lO). Veins are surrounded, or at least abaxially supported by sclerenchyma. The fertile veins divide from, and run closely parallel to the primary vein for a distance; they become sterile as they arch toward the margin (Pl.VII,fig.3). In this fer~ tile area, the secondary veins lack sclerenchyma on their abaxial surface. The extent to which these elongated fertile veins overlap determines the extent of separation of the sori or the development of the coenosoral condition. The abaxial surface of the primary vein is also fertile 41 ~ '

in this area. The conduplicately folded margins of the fertile blade tip protect the non-indusiate, mixed sori. Sporangia have a single row of cells at the base of the elongated stalk, and an annulus of 9 to 10 thickened cells. No paraphyses were found in Xiphopteris serrulata. The small wiry roots are simple in internal structure. The xylem tract consists of 2 to 3 large tracheids that may be in contact with one another or be separated by large parenchyma cells. One or 2 minute protoxylem tracheids are located at opposite ends of the tracheid line. The root is apparently diarch. The single layered phloem forms an arch on each side of the xylem from protoxylem pole to protoxylem pole. A single layered pericycle is in turn surrounded by the endodermis which consists of narrow elongated cells (Pl.VII,fig.l2). The stele of the root is surrounded by 4 to 5 layers of cortical cells; the inner most 2 or 3 layers are heavily sclerified and often completely occluded. The sclerified layer is thinner at each protoxylem pole. The outer cortical layers consist of large nucleated parenchyma cells with only slightly thickened walls. The epidermis consists of cells that are oval in cross section, and thickened on their radial and internal walls. 42

PLATE VII XiEhoEteris serrulata Figure 1. Habit. Figure 2. Frond. Figure 3. Portion of the frond showing details of venation. Figure 4. Rhizome scale. Figure 5. Cross section of the stele of the rhizome. Figure 6. Cross section of the stele of the petiole. Figure 7. Adaxial epidermal cells. Figure 8. Abaxial epidermal cells. Figure 9. Vestigial hydathode on adaxial laminar surface. Figure 10. Cross section of the lamina. Figure 11. Epidermal hairs. Figure 12. Cross section of the stele of the root. The scale indication at each figure is in millimeters. 43

9

4 44

PLATE VIII Xiphopteris serrulata Figures 1 - 29. Selected serial cross sections of the stele of the rhizome showing the origin of the leaf traces, branch traces, and root traces. The scale indication is in millimeters. 45

9

27 28 46

Xiphopteris trichomanoides The rhizome of Xiphopteris trichomanoides is erect to ascending, often branched, up to 5 em in length and 5 to 8 mm thick (Pl.IX,fig.l). The rhizome is coated with a heavy investiture of wiry roots and concolorous scales. The scales are 3 to 5 mm long, linear-lanceolate with a frequently branching tip with small terminal glands (Pl.IX, fig.4); many scales also have lateral outgrowths of 2 to 7 cells which also support terminal glandular cells. The lower 1/5 to l/4 of the scale is composed of smaller, thinner walled cells than the upper portions of the scale. This thinner walled area is particularly evident in the larger, more fully developed scales. Petioles are 3 to 10 mm long and crowded upon the stem. The blade is narrowly oblong and deeply pinnatifid (Pl.IX,fig.2), 3 to 9 em long, and 3 to 7 mm wide. The venation is pinnate, with free simple, or once forked veins that terminate in hydathodes well before the leaf margins (Pl.IX,fig.2). Long stiff trichomes are evident covering the frond. The outline of the stem is an irregular ellipse in cross section. The vascular cylinder is organized as a solenostele with overlapping leaf gaps. Leaf traces spiral off the main axis and associated with each leaf trace is a branch trace. Occasionally these branches develop, but more regularly remain dormant. Branch traces divide from 47 9

the area of the single U shaped leaf trace prior to or well after leaf gap formation (Pl.X,figs.4,13,21). Because of this variability it is difficult to determine whether the branch is more closely associated with the leaf or the main axis. Single root traces are associated with the leaf traces and are formed 'either opposite (Pl.X,figs. 11-13,17-19) or at right angles (Pl.X.fig.l). The parenchymatous pith of the rhizome consists of 40 to 70 irregular cells. Inner phloem elements are rounded to rectangular and form a layer 1 or 2 cells wide. The outer phloem elements form a layer of tissue 1 to 3 cells wide with interspersed parenchyma cells, these phloem elements are 3/4 to the same size as the internal phloem elements. Xylem is surrounded by a layer of small parenchyma cells which separate it from both the inner and outer phloem. The xylem band is 1 to 3 tracheids wide, with relatively uniform metaxylem tracheids (Pl.IX,fig.5). The pericycle is 1 to 4 cells wide and is composed of thin walled, nucleated parenchyma. The stele is bounded by the narrow elongated cells of the endodermis that display bright staining casparian strips on their radial walls. The cortex consists of 7 to 10 rows of cells. The inner 4 to 5 rows are only slightly thicker than those of the outer cortex, with exception of the cortical cells surrounding emerging leaf and root traces which are heavily occluded. The size of the cortical cells gradually 48

increases towards the outside of the stem; at the same time, the thickness of the individual cell walls decreases, so that the outer cortical cell walls are only 1/2 the thickness of the inner cortical cell walls. The epidermal cells are not distinct from the outer cortical cells. A single leaf trace enters the petiole. The central portion of the roughly circular stele is occupied by a curved band of xylem, 2 to 4 tracheids wide (Pl.IX,fig.6), the protoxylem elements are in 2 groups, 1 at each end of the xylem band. Xylem is separated from the phloem, in most areas, by a row of small parenchyma cells. The phloem is made up of 1 or 2 rows of small thin walled cells frequently interrupted by parenchyma. Phloem surrounds the xylem except at the protoxylem poles. The pericycle is composed of 1 or 2 rows of thin walled cells. Flattened endodermal cells separate the stele from the heavily sclerified cells of the cortex; the 5 to 7 rows of sclerified cortical cells are totally occluded by dense material. The epidermis is composed of large thin walled cells. Between the sclerified cortex and the epidermis there are 2 to 3 rows of cortical cells with only occasion­ al wall thickenings. Veins originate from the protoxylem poles of the xylem band which flattens out and becomes straight in cross section as it enters the leaf blade. The adaxial epidermis of the frond consists of irreg- 49

ular, sharply undulate cells that are 1/2 as wide as long. Epidermal cells superficial to the main vein are rectangu- lar with smooth side and end walls. Epidermal cells superficial to the secondary veins do not differ greatly from the epidermal cells of the intercostal regions, except at the vein endings, where the vein turns toward the adaxial surface and terminates in a large hydathode (Pl.IX, figs.7,9). The fertile veins also terminate in hydathodes. The epidermal cells at the hydathode differ from the surrounding epidermal cells. They are smaller in size, with smoother walls and lack chloroplasts and cuticle. The size of the hydathodes varies greatly, along with the number of epidermal cells involved in their formation. Abaxial laminar cells are much more irregular in shape and have more sharply undulate walls than the adaxial epidermis; and are only slightly less irregular when superficial to a secondary vein (Pl.IX,fig.8). Stomata are restricted to the abaxial surface. In cross section, both adaxial and abaxial epidermal cells display short projections into the mesophyll. The mesophyll is composed of irregular, loosely arranged parenchyma with numerous intercellular spaces (Pl.IX,fig. 9). Uniseriate, sclerified trichomes with terminal glandular cells occur on the leaf margin and both the adaxial and abaxial surfaces (Pl.IX,fig.lOc). These 50

trichomes arise from sclerified epidermal cells that are depressed in relation to the other epidermal cells (Pl.IX, figs.lOa,lOb). A second type of less common hair is found predominantly along the midrib on the abaxial surface (Pl.IX,fig.ll). These hairs are superficial in origin from small round epidermal cells, are small, less than 0.3 mm in length, branched, non-sclerified and bear club­ shaped glandular tips. Round sori are borne on raised receptacles located over a swollen region of the fertile vein at about mid­ point in its length (Pl.IX,fig.3). Sori are of the mixed type; sporangia have a single row of cells at the base of the stalk and an annulus of 13 to 16 thickened bow cells. Frequently, the sclerified epidermal hairs project from the sorus. Small, branched paraphyses are found rarely,they range in length from 0.11 to 0.15 mm and are shorter than the stalks of the mature sporangia (Pl.IX,fig.l2). The roots have a diarch stele with 2 or 3 protoxylem tracheids at each of the oppositely located poles. A

single layered phloem separated from the xyl~m in most areas by a single layer of parenchyma, surrounds the meta­ xylem tracheids. The pericycle is single layered. The stele is bounded externally by the endodermis which is composed of narrow, elongated cells (Pl.IX,fig.l3). The inner 2 to 4 cortical layers are heavily sclerified and completely occluded with a densely staining material; 51

the outer 2 to 3 layers of cortex are not heavily sclerified and contain numerous plastids. The epidermis consists of thin walled cells larger in diameter than the cortical cells. 52

PLATE IX Xiphopteris trichomanoides Figure 1. Habit. Figure 2. Frond. Figure 3. Portion of the frond showing details of venation. Figure 4. Rhizome scale. Figure 5. Cross section of the stele of the rhizome. Figure 6. Cross section of the stele of the petiole. Figure 7. Adaxial epidermal cells, hydathode. Figure 8. Abaxial epidermal cells. Figure 9. Cross section of the lamina showing a vein terminating in a hydathode. Figure 10. Sclerified epidermal trichome. a) origin from abaxial surface. b) origin from adaxial surface. c) sclerified trichome. Figure 11. Epidermal hairs. Figure 12. Paraphyses. Figure 13. Cross section of the stele of the root. The scale indication at each figure is in millimeters. 53 54

PLATE X Xiphopteris trichomanoides Figures 1 - 23. Selected serial cross sections of the stele of the rhizome showing the origin of the leaf traces, branch traces and the root traces. The scale indication is in millimeters. 55 V. GRAMMITIS

Grammitis marginella The rhizome of Grammitis marginella is erect, frequently branched, up to 2 em in length and 3 to 7 mm thick (Pl.XI,fig.l). The rhizome is covered with narrowly lanceolate, concolorous scales, 1 to 3 mm long, with highly branched tips bearing multiple glandular appendages (Pl.XI, fig.3). The roots are wiry and highly branched. Petioles are short, usually less than 2 mm in length, but may exceed 5 mm in the largest fronds and are radially arranged and crowded upon the stem. The petioles are abundantly clothed in uniseriate sclerified hairs with glandular terminal cells. Grammitis marginella is characterized by the presence of a dark sclerified blade margin. The blades are simple, oblanceolate to spatulate, from 6 mm to 8 em in length, the most common is 2 to 4 em (Pl.IX,fig.2); the usual width is 5 mm, but may exceed 9 mm in the largest fronds. Venation is pinnate with the secondary veins once forked in the broader parts of the blade. All veins end before the margin. Anastomosis between vein branches occurs. Rarely, the acroscopic branch of a vein will fuse with the basiscopic branch of the same vein (Pl.XI,fig.2). As noted by Copeland (1951) occasionally on the broader parts of the fronds, the basiscopic branch of a fertile vein may anastomose with

56 57

the basiscopic vein of the next higher fertile vein (Pl.IX, fig.2). The outline of the stem is elliptic in cross section. The vascular organization of the rhizome of Grammitis marginella is dictyostelic, with overlapping leaf gaps, but no additional perforations. Extra-axillary branches are found in association with each leaf. The leaf trace is divided into 2 vascular strands (Pl.XII,figs.4,7-9,21-23). Roots arise perpendicular to leaf and branch traces, frequently from the same meristele (Pl.XII,figs.S-7,20,22- 23). Roots exit the stem horizonally, and quickly. No roots were observed originating during the internodes. The central parenchymatous pith of the rhizome consists of 75 to 100 cells, and connects to the cortex through the parenchymatous rays of the leaf gaps. The cells of the pith are sclerified. Each vascular bundle consists of a central band of xylem that is 1 to 4 tracheids wide. Phloem surrounds the xylem except at the ends of the xylem bands in the areas of the leaf gaps. The 1 to 2 layered internal phloem is separated from the xylem by 1 or 2 rows of small parenchyma. The outer phloem is 1 to 2 elements wide, and is usually separated from the xylem by a layer of parenchy­ ma. Inner phloem elements are 1/2 to 2/3 the size of the outer phloem elements; both phloem layers show rounded to rectangular cells in cross section (Pl.XI,fig.4). A 1 to 58

3 layered pericycle surrounds the vascular tissues of each meristele. Each vascular bundle is surrounded by a single endodermis composed of rectangular to oval cells. The cortex consists of 5 to 9 layers of lightly sclerified cells with no division between inner and outer cortex. Heavily sclerified cells are seen only in areas surrounding the traces to the leaves, branches or roots. The large, thin walled cells of the epidermis are easily distingushable from the cortical cells. The cells of the epidermis are subtended by a layer or 2 of similar sized cells, that appear to be epidermal in origin as a result of periclinal division. These cells separate the epidermis from the sclerified cells of the cortex. The leaf trace enters the petiole as two separate, roughly oval xylem tracts. A group of 2 to 4 protoxylem tracheids form the adaxial end of each tract. The 1 to 3 layered phloem occurs in between the xylem tracts, and also surrounds each tract except at the protoxylem poles.' The phloem is separated from the xylem by a layer of parenchyma (Pl.XI,fig.S). Within 1 to 2 mm of the petiole base, the metaxylem tracheids of each band fuse at the middle and abaxial ends to form a single reniform xylem band with the protoxylem poles forming the lobes. At this point, the phloem forms a 1 to 2 layered ring about the xylem, except at the protoxylem poles. The stele is bounded by a ring of narrow endodermal cells. The cortex is 6 to 8 layers 59

thick, with all cells thickly sclerified and most occluded with a densely staining material. The epidermis is clearly differentiated from the cortex, with cells that are at least 2 times the size of the cortical cells, and thinner walled. At the level of xylem tract fusion, 2 small sub-lateral ridges are formed by localized sclerification of the epidermal cells. These ridges are continuous with the sclerified margins of the leaf blade. The adaxial laminar surface is composed of irregular undulate cells that are 2 to 4 times longer than wide (Pl.XI,fig.6). Epidermal cells superficial to the main vein are more rectangular with less undulation of their side walls than the epidermal cells of the intercostal areas, but these elongated cells do not extend beyond the vein endings. Epidermal cells superimposed over the later­ al veins are not different than those of the intercostal areas. Epidermal cells of the abaxial surface are more irregular with sharply undulate walls with stomata scattered randomly throughout the surface (Pl.XI,fig.7). Both epidermal surfaces bear scattered erect hairs that are uniseriate, often branched and are sclerified with the exception of the terminal glandular cell (Pl.XI,fig.8). Branched hairs occur predominantly along the midrib. In cross section, both epidermal surfaces appear to be relatively consistant in thickness and with distinct 60

cuticle layers (Pl.XI,fig.8). The mesophyll is composed of armed spongy parenchyma cells with large intercellular spaces. - Round to oval sori are borne on a raised receptacle · situated over a fusiform fertile vein (Pl.XI,fig.2). The sori are usually terminal, occasionally the tip of the fertile vein will extend beyond the receptacle. The sorus is of the mixed type. The sporangia have a single row of cells at the base of the stalk, and an annulus of 8 to 10 (mostly 9) thickened bow cells. The dark sclerified blade margin develops acropetally, by the gradual build up of sclerified cell walls in both mesophyll and epidermal cells of the margin. The margin also bears sclerified epidermal cells with glandular terminal cells. The root development is exarch, each of the 2 proto­ xylem poles consisting of 2 to 3 tracheids that are less than 1/3 the diameter of the central metaxylem tracheids. A single layered phloem surrounds the xylem except at the protoxylem poles, and is separated from the xylem by a narrow row of small parenchyma cells. The pericycle consists of a single row of large parenchyma cells (Pl.XI, fig.lO). Endodermal cells are elongated, narrow and nucleated. The cortex consists of 5 to 6 cell layers; the inner most 2 to 3 layers are heavily sclerified and frequently occluded, the outer 2 to 3 cortical layers are 61

only slightly thickened and contain numerous plastids. The single layered epidermis is composed of flattened, elongated cells. 62

PLATE XI Graimllitis marginella Figure 1. Habit. Figure 2. Fronds. Figure 3. Rhizome scales. Figure 4. Cross section of the stele of the rhizome. Figure 5. Cross section of the stele of the petiole. Figure 6. Adaxial epidermal cells. Figure 7. Abaxial epidermal cells. Figure 8. Cross section of the lamina. Figure 9. Epidermal hairs. Figure 10. Cross section of the stele of the root. The scale indication at each figure is in millimeters. 63 64

PLATE XII Grammitis marginella Figures 1 - 23. Selected serial cross sections to the stele of the rhizome showing the origin of leaf traces, branch traces and root traces. The scale indication is in millimeters. 65

. ··I

• I

~0.2 VI. DISCUSSION

Bower (1923) discussed a number of characteristics useful for comparison in determining the phylogeny of ferns. Table 1 summarizes our current understanding of these characteristics for the sporophytes of the

Grarnmitidacea~ as represented by the species examined by Nozu (1958-1960), Wilson (1966), and this study. The vascular tissue of the stem and leaf is thought to be the most reliable structure for phylogenetic comparison (Bower,l923). The general concepts concerning vascular system evolution in the ferns were outlined by Holttum (1964). The primitive type of vascular system in the ferns is protostelic. The next stage is a medullated protostele, occasionally with xylem cylinder gaps resulting from the departure of leaf traces. The gaps allow phloem to be developed internally, leading to the solenostele. Finally, by the overlapping of sucessive leaf gaps, a solenostele becomes a dictyostele. Bower (1923) states that anatomical characters are apt to follow evolutionary progress and thereafter persist. It appears that the whole range of vascular structures is found in the Grarnmitidaceae, and may be of use in discerning phylogeny of the family. The three Adenophorus species have a dorsiventral organization in regards to leaf trace origin; the other Grammitid ferns studied are radial in arrangement.

66 67

While De La Sota (1973) reports that perforations other than leaf gaps are characteristic of the rhizome of the Grammitidaceae, it may be significant that no such perforations were observed in any of these six species. Branching rhizomes are dominant in this study group. In four species; Adenophorus tamariscinus, Adenophorus hymenophylloides, Xiphopteris trichomanoides, and Grammitis marginella, the branches are extra-axillary in nature. Only in Xiphopteris serrulata are the branches rare and random in the stelar organization. References to branching, and branch trace origin in the Grammitidaceae have not been reported previously in the literature. Root propagules were observed in Adenophorus haalilio­ anus. The origin of these buds in the root pericycle and a detailed study of the development of these propagules in Adenophorus was described by White (1969). Root propagules have not been previously observed in Xiphopteris serrulata, and should be looked for in other Grammitid ferns, since they now appear to occur in species other than those belonging to Adenophorus subgenus Oligadenus (Bishop,l974). The exindusiate sorus is another characteristic of the Grammitidaceae. Sporangia of the family are characterized by a single rowed stalk, the development of this distinctive type of sporangium has been described by Wilson (1958b) for Xiphopteris serrulata. 68

The genus Adenophorus as currently defined consists of two groups of species, designated subgenera by Bishop (1974). The first group, subgenus Adenophorus consists of four species characterized by creeping rhizomes with remote fronds that are deeply bipinnatifid to tripinnatifid with irregular epidermal surfaces that bear sessile, appressed, directed glandular hairs. Adenophorus tamariscinus and Adenophorus hymenophylloides are members of this group. Evidence presented in the current study indicates that extra-axillary branch buds may also be characteristic of this taxon. This study indicates that the epidermal hairs may not be uniform, and that they are sessile in A. hymenophylloides but are short stalked and frequently branched in A. tamariscinus. Yet in both species the hairs are appressed and directed toward the apex of the blade segment or lobe. The second group, subgenus Oligadenus consists of five species characterized by roots that bear adventitious buds, erect or ascending rhizomes, and simple to pinnatifid fronds with smooth epidermal surfaces bearing branched erect hairs. Adenophorus haalilioanus is a member of this group, and clearly fits the characteristics. The presence of clavate glandular paraphyses and the strict localization of these ferns to the Hawaiian Islands has been used to justify classification of these species 69

in a single distinct genus (Copeland,l947; Wilson,l964; Bishop,l974). This study indicated the presence of other distinctive anatomical characteristics in both groups. Club-shaped hairs are found on the rhizome epidermis of each species examined. The similarity of these hairs is striking (Pl.I,fig.S; Pl.III,fig.6; Pl.V,fig.S). Each of the Adenophorus species studied has shown a distinctly differentiated cortex: A. tamariscinus, A. hymenophylloides and A. haalilioanus of the current study and A. sarmentosus as reported earlier (Wilson,l966). Perhaps the most interesting common character is the dorsiventral nature of the rhizome regardless of whether the rhizome is prostrate or erect. Holttum (1964) states that usually all members of a genus are either dorsiventral or radial in the vascular structure, and that the dorsiventral structure is not a step in onotogeny but is a specialization, best adapted to a creeping or climbing habit. Holttum (1964) outlines two kinds of evolutionary developments starting from the simple solenostelic, dorsiventral rhizomes that bear fronds alternately in two rows on the upper surface. The first line of development may be applicable to the trends seen in Adenophorus. An increase in the rows of fronds borne on the dorsal surface creates gaps in the stele corres­ ponding to the bases of the fronds. These gaps overlap, 70

so that the dorsal half of the stele approaches a dictyostele, but the ventral half of the stele, bearing only roots, is unaltered from the primitive solenostelic condition. Starting with a stelar arrangement such as seen in A. tamariscinus which corresponds to Holttum's starting point, and comparing the stelar arrangements described for A. haalilioanus and A. sarmentosus (Wilson, 1966) it appears possible that the latter two arrangements could be derived through just the system described by Holttum. Definite statements cannot be made regarding the evolutionary trends of the vascular structure and the relationships between the Adenophorus species until the remaining species have been subjected to detailed anatom­ ical studies, particularly of rhizome stelar patterns. In Copeland's (1947) broad description of the genus, both Xiphopteris serrulata and Xiphopteris trichomanoides fit the characteristics. Copeland also narrowly defines another genus Cochlidium in the same work. Recently, Bishop (1978) has redefined the genus Cochlidium and included X. serrulata in this genus, renaming it Cochlidium serrulatum. Bishop states that the presence of hydathodes will separate the genus Cochlidium from nearly all New World species of Grammitidaceae with simple fronds, and that 71

concolorous scales will remove them from many of the species included in Xiphopteris. Both species examined in this study have concolorous scales, and the hydathodes are greatly developed in X. trichomanoides whereas they are at best vestigial in X. serrulata. Bishop also defines the members of Cochlidium as having 2 to 8 celled laminar hairs with thickened inter­ cellular walls. Bishop mentions that the hairs of X. serrulata are unusual for the genus in having an elongated terminal cell, and less thickened intercellular walls. Laminar hairs of X. serrulata as seen in this study lack any thickenings, while hairs with very thick intercellular walls are seen on the fronds of X. trichomanoides. The stelar organization of Cochlidium is defined by Bishop as consisting of 1 to 3 vascular bundles each with a straight or slightly arched row of tracheids. Although a random internodal cross section of X. serrulata does frequently show individual vascular bundles, this study demonstrates the solenostelic nature of the rhizome (Pl. VIII). And indicates that the stelar organization of X. serrulata may be more truly a dissected solenostele. A dis­ sected solenostele is characteristic of X. trichomanoides. The differences in degree of dissection, and size of individual vascular strands may be a result of the stem size, X. trichomanoides being much larger than X. serrulata 72

both in length and, more significantly, in diameter. Most clearly the sori differ between the two species examined. This factor may be used to support the separation of these two species into distinct genera. The overlapping of the receptacles and the tendency of the sporangia to form a continuous mass strongly supports a coenosoral ancestry for X. serrulata. The same cannot be said of X. trichomanoides at this time. It is beyond the scope of this work to suggest which taxonomic system, Copeland's or Bishop's is most correct. However, this study does indicate some problems with the current separation of these two species into distinctly different genera, and indicates the presence of many overlapping characteristics. This work seems to support a system which retains these two species within the same genus, and indicates that a great deal more anatomical work on the species level needs to be completed before new generic lines are drawn. With so few anatomical investigations of members of the Grammitidaceae available, it is difficult to generalize about evolutionary trends in the vascular structure as shown by this taxon, or to deal with the systematic problems of the family. More comparative data is needed before any conclusions as to the evolution of this family or relationships of its species can be made. 73

I. Com arison of S te Characteristics.

ttl Q) "0 ,...... •.-I 1.0 ttl 0 ttl 1.0 ttl ;j ttl ;j ttl Cl) 0'\ ;j s:: ;j s:: ;j ;j ...-! 1-l 1-l r-1 1-l Cd 1-l Cl) Q) 0 C) 0 0 0 0 ~ ~ ...c:: Cl) ...c:: r-1 ...c:: .jJ s:: C) r-1 0 Cd 0 1-l 0 ~ Cl) 1-l s:: Cd s:: s ....-! Cd Q) Q) H •.-I ..c "0 ~ "0 Cd ;3 (.) < .jJ

Venat~on Leaf am~nar an u ar Hairs simple or ranched, erect, 2-4 celled none none none roun ova to roun terminal round, terminal Bisho ,1974 terminal un~seriate uniseriate uniser~ate niser~ate glandular glandular glandular landular 74

TABLE 1. Continued.

$-1 Q) .JJ t) cu $-1 cu ..c t) Rhizome Dissected Dissected Hedullated Dictyostele Stele 3olenostele Solenostele protostele to with leaf Radial Dictyostelic Radial gaps. Radial Radial Branching rare, extra­ Not Not random axillary Reported Reported Root rare none Not Not E_ro_pagule s Reported Reported Scale Gland-tip Gland-t~p base shape pel tate subcordate pel tate pel tate Rhizome Not Not Hairs none none Reported Reported Leaf trace single single single single circular cresent flattened flattened v v Venation ot s~mple simple s~mple Leaf pinnate pinnate pinnate pinnate Laminar Glandular Glandular Setose Stellate & Hairs 2 celled 2 types uni­ unicellular 5-8 cells & cellular setose sclerified Hydathodes vestig~al well Not Not developed Reported Reported Sorus shape l~near to round round l~near ~n and confluent dorsal dorsal 2 rows to position dorsal coenosoral Paraphyses none small, none none rare -.-

75

TABLE 1. Continued.

0 -\0 I ttl 0\ 0\ 0 til -Ln til Ln til -\0 Q) .~~ •r-1 0\ •r-1 0\ •r-1 0\ .u'"' .UQ) .u ~ .-1 .u Q) .-1 .u .-1 u •.-I s:: •.-I ~ ·r-1 s:: ~ •r-1 rc! ~ tl1 r-1 ~ ;:j ;:j CJ) ;:j .u N ~ N 0 N ttl I ef i H 0 i ttl 0 i .u 0 ..s::::'"' ttl z til z Q) z u ~ s ~~ ...... C,!)'"' ttl ...... C,!)'"' til ...... Rhizome Dictyo- Soleno- Interrupted Interrupted Stele stele stele ~olenostele Solenostele Radial Radial Radial Radial Branching extra- Not Not Not axillary Reported Reported Reported Root none Not Not Not propagules Reported Reported Reported Scale Gland-tip pelt ate base shape subcordate w/ stinging pel tate pel tate to rounded hairs Rh~zome none Not Not Not Hairs Reported Reported Reported Leaf trace paired single single single round flattened circular v Venation of simple free Not Not Leaf pinnate forked Reported Reported Laminar Glandular uni- uni- uni- Hairs branched, cellular cellular cellular sclerified sclerified Hydathodes none Not Not Not Reported Reported Reported Sorus shape oval to round round round and round, dorsal to dorsal to terminal position terminal to terminal terminal dorsal Paraphyses none none none none LITERATURE CITED

Bishop, L.E. 1974. Revision of the Genus Adenophorus (Grammitidaceae). Brittonia 26: 217-240. Bishop, L.E. 1978. Revision of the Genus Cochlidium (Grammitidaceae). American Fern Journal 68: 76-94. Bower, F.O. 1923. The Ferns. Vol. 1. Cambridge University Press. London.--- Brown, D.F.M. 1958. A Monographic Study of the Fern Genus Woodsia. Ph.D. Dissertation. University Microfilms, Inc., Ann Arbor, Michigan.

Ching, R.C. 1940. On Natural Classification of the Family Polypodiaceae. Sunyatsenia 5: 201-268. Copeland, E.B. 1947. Genera Filicum. Chronica Botanica, Waltham, Massachusetts. Copeland, E.B. 1951. Grammitis. Philippine Journal of Science 80: 93-271. Holttum, R.E. 1947. A Revised Classification of Leptosporangiate Ferns. Botanical Journal of the Linnean Society 53: 123-187. Holttum, R.E. 1949. The Classification of Ferns. Biological Reviews 24: 267-296. Holttum, R.E. 1964. The Evolution of the Vascular System in Ferns with Special Reference to Dorsiventral Rhizomes. Phytomorphology 14: 477-480. Johansen, D.A. 1940. Plant Microtechnique. McGraw-Hill Book Co., Inc. New York. Nozu, Y. 1958-1960. Anatomical Notes on Microloltpodium, Scleroglossum, and Grammitis, 1-3. Journa o Geobotany. 7: 102-107; 8: 1-5; 9: 4-9.

Sota, E.R. De La, 1973. On the Classification and Phylogeny of the Polypodiaceae. In: The Phylofeny and Classifi­ cation of the Ferns. A.C. Jermy, J .. Craooe, B.A. Thomas,~d~Supplement No. 1 to the Botanical Journal of the Linnean Society. Vol 67. Academic Press, London.

76 77

Stokey, A.C. 1951. The Contribution by the Gametophyte to ~ i Classification of the Homosporous Ferns. Phytomorphology 1: 29-58. Stokey, A.C. and L.R. Atkinson, 1958. The Gametophyte of the Grammitidaceae. Phytomorphology 8: 391-403. White, R.A. 1969. Vegetative Reproduction in the Ferns. II. Root Buds in Amhhoradenium. Bulletin of the Torry Botanical Clu 96: 10-19. Wilson, K.A. 1958a. Ontogeny of the Sporangium of Phlebodium (Pol~podium) aureum. American Journal of Botany 45: 483- 91. Wilson, K.A. 1958b. Ontogeny of the Sporangia in Xiphopteris serrulata and PArrosia nuda. Journal of the Arnold Arboretum 39: 47 -493. ------Wilson, K.A. 1964. Notes on the Hawaiian Fern Genus Adenophorus. American Fern Journal 54: 68-70. Wilson, K.A. and F.R. Rickson. 1966. An Anatomical Study of the Hawaiian Fern Adeno~horus sarmentosus. Pacific Science 20: 114-11 . ~