a new fossil fern assignable to gleicheniaceae from late cretaceous ...

American Journal of Botany 84(4): 483–493. 1997.

A

GLEICHENIACEAE SEDIMENTS OF NEW JERSEY1

NEW FOSSIL FERN ASSIGNABLE TO

FROM

LATE CRETACEOUS

MARIA A. GANDOLFO,2 KEVIN C. NIXON, WILLIAM L. CREPET, GENE E. RATCLIFFE

AND

L.H. Bailey Hortorium, 462 Mann Library, Cornell University, Ithaca, New York 14853-4301 The recent discovery of well-preserved charcoalified rhizomes, petioles, pinnules, sori, and spores from the Upper Cretaceous of New Jersey provides the basis for the description of a new gleicheniaceous fern, Boodlepteris turoniana. The fossils were collected from unconsolidated sediments of Turonian age (ø 90 MYBP, million years before present; Raritan/ Lower Magothy Formation, Potomac Group). These deposits are rich in angiosperms, but also have a limited representation of fern and gymnosperm remains. Fossil specimens from this locality are particularly remarkable in that minute detail, including anatomical features, are often preserved. Some Boodlepteris specimens have cell by cell preservation that reveals the nature and structure of the stele in rhizomes and petioles, and others show minute details of the sori borne on fertile pinnae. Although these specimens are not in organic connection, there are sufficient structural and anatomical details preserved to confidently suggest that they belong to the same taxon. Cladistic analysis of the fossils, both separately and as a reconstruction, support assignment of Boodlepteris to the extant family Gleicheniaceae. Key words:

Cretaceous; fossil; fern; Gleicheniaceae; rhizomes; sori; pinnules; cladistics.

Recently, an unprecedented diversity of angiosperm fossil flowers have been reported from a locality in New Jersey of Turonian age (ø 90 MYBP, million years before present; Crepet et al., 1992; Herendeen, Crepet, and Nixon, 1993, 1994; Nixon and Crepet, 1993; Crepet and Nixon, 1994). These fossils typically are fusainized (charcoalified) and have exceptional cellular detail. In this paper we describe fossil fern rhizomes, petioles, and sterile and fertile pinnae from the Turonian locality that have a mosaic of characters of the extant genera of the family Gleicheniaceae. The fossils characterized here are significant because of the excellent preservation of the cellular and anatomical detail, and even though the fossils are not in organic connection, it is possible to assign them to a genus and species within the Gleicheniaceae. Cladistic analyses of the fossils both as separate organs or as a reconstruction confirm their gleicheniaceous affinity.

and unpublished data), and various leaves and strobili of gymnosperms (Gandolfo, Nixon, and Crepet, 1996; and unpublished data). Fossils are charcoalified (fusainized) and three-dimensional with extraordinary preservation of cellular detail. This type of preservation has been interpreted to be the result of rapid charcoalification during forest fires (Friis, Crane, and Pedersen, 1988). Fossils were prepared by dissolving the unconsolidated sediment in warm water, sieving through successively finer screens, and cleaning the resultant organic material with strong detergent to remove excess clay. Sand was eliminated by gently swirling to suspend the fossils and then decanting the suspension of organic materials. Remaining adhering minerals were removed by treating the fossils with hydrofluoric acid followed by several rinses with distilled water. Fossils were air-dried and sorted with a Zeiss SV-8 stereosmicrospe. Selected specimens were mounted on stubs and sputter-coated with gold/palladium in preparation for examination with a Hitachi 4500 scanning electron microscope (SEM). Specimens are stored on SEM stubs in specimen boxes, and deposited in the Paleobotany Collection of the L.H. Bailey Hortorium, Cornell University (CUPC).

MATERIALS AND METHODS

Cladistic analyses—A matrix of morphological characters was developed for extant genera of the Gleicheniaceae (Stromatopteris, Gleichenia, and Dicranopteris) and the outgroups Osmundaceae, Schizaeaceae, and Hymenophyllaceae. The resulting matrix has six extant terminals and 15 morphological characters (Table1). No polymorphisms were encountered; all question marks in the matrix refer to unobserved or unknown data. One variation of the matrix (‘‘matrix a’’) included the fossil fern material treated as separate terminals based on detached organs (Petiole, Pinnule, Rhizome). A second variation of the matrix (‘‘matrix b’’) treated the fossils as a single terminal reconstruction based on all three organs (Boodlepteris). The two matrices were analyzed separately with the programs Hennig86 (Farris, 1988) and NONA (Goloboff, 1993). Because of the small number of terminals, it was possible to analyze both matrices in Hennig86 with the ‘‘ie’’ option (implicit enumeration, which is equivalent to branch and bound and is guaranteed to find all most parsimonious trees). In the case of matrix a (the fossils treated as separate organs), the resulting multiple trees were filtered using NONA to discard topologies that included branches with minimum length of zero steps. It was not necessary to perform additional tree searches in NONA on either matrix since the ‘‘ie’’ option of Hennig86 is guaranteed to find all most parsimonious trees.

Fossil collection and preparation—The fossils described in this paper were collected from the lower part of the exposure in the Old Crossman Clay Pit (Raritan or Lower Magothy Formation). This outcrop is exposed in Sayreville, New Jersey and its age has been estimated as Turonian (Upper Cretaceous, 88.5–90.4 MYBP) on the basis of pollen (Brenner, 1963; Doyle and Robbins, 1977; Grimaldi, Beck, and Boon, 1989; Harland et al., 1989). The specimens were found in association with abundant angiosperm flowers and fruits (Crepet et al., 1992; Herendeen, Crepet, and Nixon, 1993, 1994; Nixon and Crepet, 1993; Crepet and Nixon, 1994), at least one other fern taxon (Ratcliffe et al., 1995; 1 Manuscript received 27 February 1996; revision accepted 3 October 1996. The authors thank J. Svitko for assistance with laboratory work and with SEM, and the L. H. Bailey Hortorium for access to collections. We also want to acknowledge Judith Skog and Gar Rothwell for their comments on this paper. This study was supported in part by NSF grant DEB 9420512 to WLC and KCN. 2 Author for correspondence.

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Figs. 1–11. Boodlepteris turoniana. 1. Lateral view of the rhizome. Note dorsiventral symmetry; petioles at upper side. CUPC 1034. 2. Lateral view of the rhizome. Note adventitious roots at lower side and petioles at upper side. 3. Top view of the rhizome. See the rachides/petioles arising from it; petioles with C-shaped vascular bundle. 4. Lateral view of the rhizome. Note the protostele and sclerenchyma replacing the epidermis. Figs. 1–4, scale bars 5 0.3 mm. 5. Detail of the protostele, note the sclerenchyma formed by very thick-walled fibers. Scale bar 5 33 mm. 6. Detail of the protostele, illustrating the compression of sclerenchyma at the lower side. Scale bar 5 0.1 mm. 7. Other side of the protostele. Scale bar 5 0.1 mm. 8. Detail of the adventitious roots, epidermal cells, and bases of trichomes (arrow). Scale bar 5 0.1 mm. 9. Overall view of an immature

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ET AL.—A NEW FOSSIL

SYSTEMATICS Taxonomy and fossil history of Gleicheniaceae—The Gleicheniaceae are an ancient family of leptosporangiate ferns, as indicated by paleozoic fossils from China (Tryon and Tryon, 1982; Tidwell and Ash, 1994). The family comprises ø 130 living species placed in one, or sometimes as many as six, genera (Bower, 1926; Holttum, 1957a, b; Ogura, 1972; Tryon and Tryon, 1982; Kramer, 1990; Punetha and Kaur, 1990). Although there is some disagreement among different authors over generic limits, three taxa (as genera or subgenera) appear consistently in all treatments: Gleichenia Smith, Dicranopteris Bernhardi, and Stromatopteris Mettenius. The most prominent and easily recognized character separating Gleicheniaceae from related fern groups is pseudodichotomy of the leaves, in which growth of the rachis or petiole is arrested by the formation of a dormant bud, while the lateral pinnae continue growing (Boodle, 1901; Bower, 1926; Eames, 1936). Holttum (1957b) in the most recent treatment of the entire family Gleicheniaceae recognized three genera, maintaining Stromatopteris as distinct from Gleichenia and Dicranopteris. Stromatopteris is confined to New Caledonia, while the others have pantropical distributions. Stromatopteris differs from other Gleicheniaceae in the type of paraphyses and in growth habit. Dicranopteris differs from Gleichenia in the nature of the trichomes of the foliage and rhizomes, absence of scales on the rhizomes, in the size and number of sporangia per sorus, in the absence of paraphyses in the sori, and in the venation pattern of the pinnules. Gleichenia has trichomes and scales on the leaves and rhizomes and paraphyses associated with the sori. The fossil record of the family dates from the Paleozoic. The three fossil genera described from China, Chansitheca and Oligocarpia (Rege, 1920; Halle, 1927) from the Upper Carboniferous and Szea from the Permian (Yao and Taylor, 1988) are the oldest representatives of the family. However, there is insufficient information about the sori, sporangia, and spores of Chansitheca and Oligocarpia to be confident of their affinities with Gleicheniaceae (Bower, 1926; Yao and Taylor, 1988; Taylor and Taylor, 1993). By the Mesozoic, the family Gleicheniaceae was already well established in both hemispheres as evidenced by the fossil record. Five species of Gleichenites based on sterile and fertile pinnules have been described from the Early and Middle Triassic of Argentina (Herbst, 1962 a, b, 1972), and a single species of Antarctipteris based on rhizome and petioles of similar age has been described from Antarctica (Millay and Taylor, 1990). During the Upper Triassic, isolated spores assigned to Gleicheniidites appear in New Zealand (de Jersey and Raine, 1990). In the northern hemisphere, various genera collected in Upper Triassic sediments of the United States and Greenland have been doubtfully assigned to Gleicheniaceae.

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TABLE 1. Data matrix used for the cladistic analyses. Variation of the matrix: ‘‘matrix a’’ includes the fossil fern material treated as separate terminals (Petiole, Pinnule, Rhizome); in ‘‘matrix b’’ the fossil is treated as a single terminal reconstruction (Boodlepteris). Characters 0–14

Osmundaceae Schizaeaceae Hymenophyllaceae Stromatopteris Gleichenia Dicranopteris Fossil rhizome Fossil petiole Fossil pinnule Boodlepteris

00000 00000 10000 11111 01101 00101 1?01? ????? ????? 1?01?

12101 02101 02101 11010 11110 10111 1101? 1101? ????0 11010

10000 00011 01?10 11101 11101 11201 ????? ????? 11200 11200

Four gleicheniaceous genera have been described from the Cretaceous based on megafossils: Gleichenoides from Malaysia, Gleichenopsis from Greenland, Didymosorus from Germany (Tidwell and Ash, 1994) and Gleichenia from the United States (Rushforth, 1971; Skog and Dilcher, 1994). Isolated spores are locally abundant in the northern hemisphere during this period and several species have been described (Brenner, 1963; Bolchovitina, 1966). TAXONOMIC TREATMENT Family Gleicheniaceae Boodlepteris gen. nov., Gandolfo Type species—Boodlepteris turoniana Gandolfo Generic diagnosis—Rhizomatous. Cortex of the rhizome and petiole divided into two layers; vascular bundle C-shaped, the metaxylem not distinguishable from the protoxylem. Petiole with endodermis only externally around bundle, the metaxylem with annular or spiral tracheids, the protoxylem lacking spiral tracheids. Leaves compoundly divided, petiolate, with at least some dichotomous or pseudodichotomous branching of the rachis, but the overall form and branching pattern of the rachis unknown, attached to the rhizome in a single row. Ultimate pinnules arranged pinnately. Secondary veins of pinnules bifurcated at least once. Sori grouped on abaxial surface of lamina, lacking an indusium or false indusium. Sporangia clavate, clustered in groups of 10–20 sporangia. Spores smooth with trilete scar. Boodlepteris turoniana sp. nov., Gandolfo Holotype—CUCP 1043 (Fig. 25). Paratypes—CUCP 1009, 1010, 1011, 1012, 1014,1015, 1016, 1017, 1018, 1019, 1020, 1021, 1023, 1024, 1025, 1026, 1027, 1028, 1029, 1030, 1032, 1033, 1034, 1035, 1036, 1037, 1038, 1039, 1041, 1042, 1044, 1045.

1013, 1022, 1031, 1040,

← frond. Observe the circinnate bipinnate pinnae. Note trichomes along the center of the rachis and the pinnules. CUPC 1023. Scale bar 5 0.2 mm. 10. Circinnate pinna showing trichomes. CUPC 1028. Scale bar 5 0.2 mm. 11. Detail of anatomy of the circinate pinna showing the layer of sclerenchyma and the C-shaped vascular bundle. CUPC 1033. Scale bar 5 0.3 mm.

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Type locality—Old Crossman Clay Pit, Sayreville, New Jersey, USA. Age and stratigraphic position—Late Turonian, Lower Magothy Formation, South Amboy Fire Clay. Species diagnosis—as for the genus. Species description—Rhizomatous stem with dorsiventral symmetry, protostelic; stele surrounded by sclerenchyma formed by thick-walled fibers. The rhizome bears unbranched unicellular trichomes in sheltered areas, and bases of trichomes are persistent on other surfaces. Roots arising from the ventral side of the rhizome, fronds (petioles) arising from the dorsal side. Fronds with circinate vernation, dichotomous or pseudodichotomous, with at least one order of branching; petiole lacking epidermis (presence unknown), with a cortex and C-shaped endarch vascular bundle, the later completely enclosed by endodermis. Pinnules of Pecopteris type, alternate and free, with a longitudinally striate rachis, attached at acute angle along the entire base, margin entire and apex obtuse or acute, midvein distinctive, secondary veins emerging from the midvein, slightly curved and forked once, one secondary vein entering from the rachis in the basal side of the pinnule; epidermis of pinnae with trichomes on both surfaces, epidermal cells puzzle-like, with interlocking undulating anticlinal walls, stomata anomocytic. Sori exindusiate, 3–5 on adaxial surfaces of the pinnules, consisting of 10–20 sporangia attached to a receptacle; paraphyses and scales intermixed with sporangia. Sporangia clavate with short stalk four cells thick, annulus formed by only one row of cells; stomium longitudinal; spores smooth and trilete. Etymology—The generic name Boodlepteris is proposed in honor of L. A. Boodle for his contribution to knowledge of the family Gleicheniaceae. Description and remarks—The rhizomatous stem fragment is at least 2.5 mm long and 1.1 mm in diameter and circular in cross section with dorsiventral symmetry (Figs. 1–4). The protostele is circular in cross section and is surrounded by a thick layer of sclerenchyma (Fig. 5). The stele appears to be thinner toward the ventral side. The sclerenchyma is composed of thick-walled fibers (Figs. 6–7). Adventitious roots 0.13–0.17 mm in diameter arise from the ventral (presumed lower) side of the rhizome (Figs. 1, 2, 7, 8); fronds (petioles) emerge from the dorsal (presumed upper) side (Figs. 1–3). The rhizome bears trichomes on the ventral side (Fig. 8), but they are absent on the dorsal side. The fronds are bipinnate, with circinate vernation; the rachis is branched dichotomously or pseudodichotomously (Figs. 9, 10). Simple trichomes occur adaxially along the center of the rachis and are prominent among the unfolded pinnae (Figs. 9–11). Anatomically, the coiled rachides show a C-shaped vascular bundle (Fig. 11). The petioles are circular in cross section, at least 4 mm long and 0.8–1.4 mm in diameter (Fig. 12). Each petiole has a cortex and a vascular bundle. The cortex is 0.1-0.4 mm thick, composed of very thickwalled fibers with simple circular pits (Figs. 14, 15). The C-shaped vascular bundle is 0.5–0.8 mm diameter with

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incurved margins (Figs. 12, 13, 18). Two endarch protoxylem poles are visible (Figs. 13, 18, arrows) and the metaxylem consists of tracheids with broad scalariform pitting and tracheids with simple, opposite lateral pits (Figs. 19–21). The vascular bundle is enclosed completely by a single-layered endodermis (Figs. 13, 16, 17). Pinna rachides are longitudinally striate (Figs. 22, 23). Sterile and fertile pinnules are alternate, 0.3-1.6 mm long, emerging from the rachis at moderately acute angles (708). Pinnules are free from each other, of the Pecopteris type with an entire margin and acute to rounded apex (Figs. 22–26). A prominent midvein enters each pinnule and branches once before reaching the apex. Secondary veins emerge from the midvein at a narrow acute angle (458–508) with a slightly curved course and fork once. An additional intermediate vein originates at the rachis and approaches the basal margin of each pinnule (Figs. 27, 28). Epidermal cells of the adaxial and abaxial surfaces of the pinnules are puzzle-like with interlocking undulating anticlinal walls (Fig. 29). Stomata are anomocytic and arranged in rows parallel to the veins. Trichome bases are scattered among the epidermal cells (Figs. 28, 30). Each fertile pinnule bears 3–5 sori on the abaxial surface occupying almost all of the surface area. The sori (0.32–0.65 mm in diameter) include 10–25 sporangia in a hemispherical arrangement and lack indusia (Figs. 24–26, 31, 32). In addition to sporangia, paraphyses and scales are attached to the circular receptacle (Figs. 25, 26, 32, 37). The sporangia are clavate, ø 0.2 mm long and ø 0.01 mm wide; the stalk is four cells thick (Fig. 35). Each annulus is formed by a row of elongate cells interrupted by a longitudinal stomium (Figs. 32–34, 39). The spores are trilete (14–25 mm in diameter) and the wall is smooth (Figs. 40, 41). RESULTS The analysis of the matrix with Boodlepteris scored as a single reconstructed terminal resulted in a single most parsimonious tree with a length of 23 steps, consistency index (CI) of 0.73, and retention index (RI) of 0.73. This tree is presented in Fig. 44 (see Appendix 1 for character descriptions). In this tree Boodlepteris is nested within a monophyletic Gleicheniaceae as a sister taxon to Stromatopteris, with Gleichenia in turn a sister taxon of the Boodlepteris–Stromatopteris clade, and Dicranopteris a sister taxon to the remainder of Gleicheniaceae. Analysis of the matrix in which the three detached fossil organs were treated as separate terminals resulted in 26 equally parsimonious trees of the same length as the previous analysis, 23 steps, with a CI of 0.73 and RI of 0.75. When these 26 trees were filtered through the ‘‘unique’’ option of NONA, only five trees with fully supported nodes remained. In these five trees, the three fossil terminals always form a monophyletic group with the three extant genera of Gleicheniaceae, as indicated by the strict consensus (Fig. 45), and otherwise the outgroup relationships are identical. In all five trees, the relationships of the extant genera of Gleicheniaceae are identical with the previous analysis as well: (Dicranopteris (Gleichenia-Stromatopteris)). The variation in topology in these five trees is due solely to different positions of the fossil organs within the Gleicheniaceae clade. This vari-

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Figs. 12–21. Boodlepteris turoniana. 12. Overall view of a petiole, illustrating the cortex and vascular bundle. CUPC 1035. Scale bar 5 0.3 mm. 13. Detail of the C-shaped vascular bundle surrounded by the cortex and the endodermis. Note the bilaterally symmetric stele with the incurved ends. Scale bar 5 0.1 mm. 14. Longitudinal view of sclerenchyma; detail of the fibers with the simple and circular pits. Scale bar 5 7 mm. 15. Transverse view of the sclerenchyma; note the thick wall of the fibers. Scale bar 5 7.5 mm. 16. Endodermis (arrows). Scale bar 5 27 mm. 17. Detail of endodermal cells (arrows). Scale bar 5 12 mm. 18. Recurved end of the endarch xylem, arrow showing protoxylem pole. Scale bar 5 70 mm. 19. Detail of metaxylem; tracheids with circular and simple pits. Note rest of primary wall on some of them. CUPC 1037. Scale bar 5 17 mm. 20. Detail of the scalariform tracheids. CUPC 1036. Scale bar 5 17 mm. 21. Detail of tracheids with opposite lateral pits. Note the primary wall. Scale bar 5 12 mm.

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Figs. 22–30. Boodlepteris turoniana. 22, 23. Pinnules with entire margin and obtuse apex. CUPC 1021, scale bar 5 0.2 mm; CUPC 1018, scale bar 5 0.3 mm. 24–26. Pinnules with sori. CUPC 1040, scale bar 5 0.4 mm; CUPC 1043, scale bar 5 0.3 mm; CUPC 1044, scale bar 5 0.3 mm. 27. Detail of the dichotomous open venation; see the secondary vein arising from the petiole (arrow). CUPC 1021, scale bar 5 0.1 mm. 28. Detail of the venation; note the stomata parallel to the veins. CUPC 1022, scale bar 5 0.2 mm. 29. Puzzle-like epidermal cells. CUPC 1011, scale bar 5 0.27 mm. 30. Anomocytic stomata. CUPC 1018, scale bar 5 0.9 mm.

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Figs. 31–35. Boodlepteris turoniana. 31. Sorus. CUPC 1042, scale bar 5 50 mm. 32. Detail of the sorus. Note the receptacle area (arrow), arrangement of the sporangia and the presence of paraphyses. CUPC 1044, scale bar 5 90 mm. 33. Sporangium, detail of the longitudinal stomium. Scale bar 5 20 mm. 34. Sporangium, detail of the annulus. CUPC 1040, scale bar 5 15 mm. 35. Section of stalk of sporangium. Note the remains of the four cells. CUPC 1042, scale bar 5 10 mm. 36. Sorus of the extant species Dicranopteris pectinata (Wild.) Und, BH, Rio de Janeiro, O. C. James #1875. Scale bar 5 0.1 mm.

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Figs. 37–43. 37. Paraphysis of a sorus of Boodlepteris turoniana. CUPC 1040, scale bar 5 20 mm. 38. Paraphysis of a sorus of the extant Gleichenia bolanica Ros. BH, Flora of New Guinea, Hoogland & Schodde 7029. Scale bar 5 33 mm. 39–41. Boodlepteris turoniana. 39. Sporangium. CUPC 1042, scale bar 5 33 mm. 40. Spores in the sporangium. Scale bar 5 7 mm. 41. Trilete spore. Scale bar 5 4 mm. 42. Sporangium of the extant Stromatopteris moniliformis Mett. BH s/n. Scale bar 5 70 mm. 43. Spore of Gleichenia bolanica Ros. BH, Flora of New Guinea, Hoogland & Schodde 7029. Scale bar 5 5 mm.

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Fig. 44. Fig. 45.


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Single most parsimonious cladogram when Boodlepteris is treated as a single reconstruction.

Strict consensus of five equally parsimonious cladograms when Boodlepteris is treated as three separate organs.

ation results in a consensus that is completely unresolved within the Gleicheniaceae clade (Fig. 45). DISCUSSION Cladistic analyses—Cladistic analyses support the placement of all three fossil organs in a clade with the extant genera of Gleicheniaceae. Analyses that treat these separate organs as the reconstructed fern Boodlepteris result in a single tree with Boodlepteris well nested within Gleicheniaceae as a sister taxon of Stromatopteris. Because the length of the trees in both analyses is identical (23 steps), it is equally parsimonious to assume that the detached organs represent a single taxon (i.e., it does not add length to the tree to assume this) as to assume that they are different taxa. Further support for conspecificity of all three organs is the independent corroboration that each belongs to the Gleicheniaceae clade, and no other organs with gleicheniaceous affinities are known from the locality. Inclusion of fossil terminals in these cladistic analyses results in cladograms that are identical to analyses excluding the fossils, in terms of extant genera. Thus, the fossil terminals, even though they have been scored as missing for several characters, do not affect the relationships of extant taxa in these cladograms. Thus, while the fossils do not change our view of modern relationships, cladistic analysis is useful in determining the best placement of the fossils in relation to modern taxa (Nixon, 1996). Morphology and anatomy—The characters observed in these fossils are a mosaic of characters found in the extant and fossil genera of Gleicheniaceae. The Gleicheniaceae are widely considered (with Hymenophyllaceae and Schizaeaceae) to be one of the most primitive families of the leptosporangiate ferns (Tidwell and Ash, 1994). Although other works exist, the studies of Hymenophyllaceae, Gleicheniaceae, and Schizaeaceae by Boodle (1901) provide the most detailed description of the anatomy of these families. Later, Bower (1926) reanalyzed the taxonomy of the families and summarized pre-

viously published work. Chrysler (1943, 1944) and Holttum (1957a, b) contributed extensive papers about the anatomy of specific organs of the Gleicheniaceae. Ogura (1972) published the most recent text on comparative anatomy and vegetative organs of the pteridophytes. Based on these works, we compared Boodlepteris turoniana with the extant and fossil genera of Gleicheniaceae. Comparison with extant Gleicheniaceae—The stem in extant Gleicheniaceae is a creeping rhizome, with dorsiventral symmetry bearing roots distributed in rows or irregularly on the ventral side, and leaves placed apparently in a single row or tristichously on the dorsal side (Boodle, 1901; Bower, 1926). This pattern is also seen in Boodlepteris. In cross section, both extant Gleicheniaceae and Boodlepteris rhizomes are circular and have the same distribution of tissues as well as cell types. The fronds of Boodlepteris are at least dichotomously branched and pinnate with circinate vernation such as in the extant genera of Gleicheniaceae. Anatomically, the petioles of modern genera of the family and Boodlepteris have a general resemblance to the rhizome. In cross section, the same layers are observed, the cortex composed of sclerenchyma and the vascular bundle (endodermis and stele). The vascular bundle is mesarch and shows a C-shaped xylem with incurved margins with internal phloem and a mass of sclerenchyma and parenchyma (Boodle, 1901; Bower, 1926; Chrysler, 1943, 1944) as in Boodlepteris. The extant Gleicheniaceae present three types of endodermis, and this is one of the characters commonly used in the taxonomy of the family. Boodlepteris has the same type as Gleichenia and Stromatopteris, in which the endodermis surrounds the bundle as a whole but is missing from the internal, infolded part of the C-shaped bundle (Ogura, 1972). This differs from the endodermis of Dicranopteris, which is enfolded into the internal part of the vascular bundle. The cellular type of the protoxylem and metaxylem is used to differentiate Gleichenia and Dicranopteris from Stromatopteris. In Boodlepteris and Stromatopteris, the protoxylem and me-

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taxylem are composed of the same type of tracheids and only are recognized by the different size. The pinnules of the modern genera of Gleicheniaceae have entire margins, rounded to acute tips, and anomocytic stomata on the adaxial side (Van Cotthem, 1973). Boodlepteris shares these characters. Although all the extant genera have trichomes and scales, only Stromatopteris and Boodlepteris have them associated with the sori. One of the characters most used for segregating the genera of the family is the pattern of venation. The venation of the pinnules of the extant Gleicheniaceae consists of a primary vein and secondary veins with or without bifurcation (Tryon and Tryon, 1982; Punetha and Kaur, 1990). Gleichenia, Stromatopteris, and Boodlepteris have simple or one-forked secondary veins. The sori in the modern genera of Gleicheniaceae are superficial, and consist of a circular receptacle bearing a variable number of sporangia, lacking an indusium (Fig. 36) and sometimes with associated paraphyses (Figs. 36, 38) as in Boodlepteris. The sporangia of the extant Gleicheniaceae are pear-shaped with a very short stalk, an annulus consisting of a simple row of cells, which is complete around the sporangium head and only interrupted by the stomium (Fig. 42); the spores can be trilete (Fig. 43) or monolete (Tryon and Tryon, 1982; Tryon and Lugardon, 1991) and the number of spores varies between 16 and at least 794 depending on the size of the sporangium (Bower, 1926).

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least once before reaching the margin. G. potrerillensis has pinnules attached at a moderately acute angle (558– 608) and the venation consists of a straight primary vein with secondary veins that lack bifurcations. Although Boodlepteris has the same type of pinnules, the angle of insertion and the pattern of venation are different from all the South American species. The fossils described by Rushforth (1971) as Gleichenia comptoniaefolia and G. delicatula also differ from Boodlepteris; the venation in the first species seems to be formed (based on the drawings) by a primary vein with straight course and secondary veins bifurcated once, and in the second species, the primary vein is identical but the secondary veins are not forked. There is no mention of trichomes or scales in any description of fossil taxa belonging to the family Gleicheniaceae. In summary, Boodlepteris turoniana is consistent with diagnostic characters of Gleicheniaceae. Boodlepteris and extant Gleicheniaceae are similar in the symmetry, the loss of epidermis, internal anatomy and form of the stele of the rhizome, the model of branching of the pinnae, histology of the petiole including the stele, pinnule type, their epidermal features and venation pattern of the pinnules, and the form and characteristics of the sori. These characters argue unequivocally for the inclusion of Boodlepteris within the Gleicheniaceae, consistent with the results of the cladistic analyses. LITERATURE CITED

Comparsion with other fossil Gleicheniaceae—The rhizome of Boodlepteris is similar to the fossil rhizome Antarctipteris from Antarctica in the distribution of tissues, except that in the latter the stele is exarch (Millay and Taylor, 1990), in contrast to the circular protostele of Boodlepteris, which seems to be endarch. The shape of the vascular bundle of the petiole is another difference between Antarctipteris and Boodlepteris. In Antarctipteris it is V-shaped or W-shaped (Millay and Taylor, 1990) and Boodlepteris is C-shaped. The pinnules of the fossil genera and Boodlepteris also differ. In Szea sinensis from the Early Permian of China, the fronds are at least bipinnate, the pinnae are attached at acute to moderate angle (508–708) and are cladophleboid type with a crenate or serrate margin at the base of the frond and entire toward the apex, and the secondary venation is sympodial and dichotomizes 2–3 times (Yao and Taylor, 1988). Boodlepteris thus differs from Szea in the type and margin of pinnules and their venation. Sterile and fertile fronds of Gleichenites juliensis from the Middle Jurassic, G. san-martini and G. argentinica from the Lower Cretaceous of Patagonia, and G. potrerillensis from the Middle Triassic of Mendoza, Argentina have fronds at least bipinnate with pinnules typically pecopteridoid and with entire margins (Herbst 1962 a, b, 1972). The Patagonian fossils have the pinnules inserted at approximately right angles (808–908) but differ in the venation pattern; in G. juliensis the primary vein follows a zigzag course and the secondary veins are once- or twicebifurcated before reaching the margin, while in G. sanmartini the course of primary vein is straight and forked once close to the tip of the pinnule, and the secondary veins are simple. In G. argentinica the main vein is slightly curved and the secondary veins are bifurcated at

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