Ordinary Epidermal Cells Research Articles

Anatomical and ultrastructural adaptations of seagrass leaves: an evaluation of the southern Atlantic groups.

Seagrasses, which form an integral part of the worldwide coastal habitat, are considered highly relevant from an ecological point of view. Due to the scarcity of anatomical information, the present study analyzed the morphoanatomy, histochemistry, and ultrastructure of Halophila decipiens, Halodule wrightii, and Ruppia maritima leaves, discussing their adaptations to the marine environments observed throughout the southwestern tropical and subtropical Atlantic coast. The leaves of these three species feature a uniseriate epidermis with the presence of chloroplasts in large quantities and absence of stomata. The vascular system consists of a central vascular bundle with sieve tube elements of the phloem and protoxylem lacunae, as well as small vascular bundles near the leaf margins. The leaves of H. decipiens possess trichomes, but no mesophyll in the leaf margins. The mesophyll of H. wrightii and R. maritima is homogeneous with chlorenchyma cells and air lacunae scattered throughout the leaf. The histochemistry analysis revealed the absence of amyloplasts and the presence of proteins in the outer periclinal walls of ordinary epidermal cells of the three species. It was also possible to detect the presence of idioblasts containing phenolic compounds in H. decipiens and R. maritima. The ultrastructural analysis of the three species revealed many elliptical chloroplasts, with organized thylakoids, expansion of the epidermal cell wall into the cytoplasm, and a thin cuticle. Hydropoten were also observed in the three specimens. The results show that the species analyzed have important adaptations which enable their survival in the marine environment.

In vivo labelling of Anagallis arvensis L. cells with green fluorescent protein

A few methods only enable to follow the fate of plant cells in vivo. One of the most promising is using the Green Fluorescent Protein (GFP). In our preliminary study we set up the experimental system enabling labelling of <em>Anagallis arvensis</em> cells with this marker. We prepared an expression plasmid containing red-shifted <em>gfp</em> with optimised translation start site context, under the control of CaMV 35S transcription promoter. The construct was introduced into <em>A. arvensis</em> cells by particle bombardment. We developed two methods of material preparation for this transformation: in vitro cultured stem internodes with regenerating adventitious shoots (the earliest stages of regeneration); and shoot tips with temporarily exposed apices. The reflected light fluorescence microscope Olympus with the set of filters U-MNB designed for fluorescein detection enables the observation of GFP fluorescence. Both ordinary epidermal cells and stomata guard cells were transformed. Their fluorescence was observed for up to 14 days. Artefacts (autofluorescence of glandular trichomes and faint green glowing of meristematic tissue) could be overcome by the optimisation of the filter set.

Leaf Cuticle Anatomy and the Ultrastructure ofGinkgoites ticoensisArchang. from the Aptian of Patagonia

The leaf cuticle of the Ginkgoites ticoensis Archang. type material from the Aptian Anfiteatro de Tico Formation in Patagonia, Argentina, is fully characterized with additional scanning and transmission electron microscopic observations. Many new anatomical and ultrastructural cuticular features are identified in the four-lobed leaf of G. ticoensis: the leaf shows a hypostomatic and papillate laminae, straight and pitted anticlinal and granulate periclinal walls, actinocytic stomata with between five and seven papillate, striate subsidiary cells, and guard cells with anticlinal smooth walls. The TEM studies on ordinary epidermal cells, papillae, subsidiary cells, and guard cells reveal general ultrastructural features of Ginkgoaceae: an outer polylamellate layer A made with A1 and a granular inner layer A2; A1 with an upper part A1U with continuous and straight translucent lamellae; a lower part A1L with significantly disrupted and waving translucent lamellae; and the fibrillar cuticular layer B1 as the i...

Secretory structures of Ipomoea asarifolia: anatomy and histochemistry

Ipomoea asarifolia (Desr.) Roem. & Schult., Convolvulaceae, is a weed that infests agricultural areas and is toxic to cattle. In spite of its toxicity, the leaves of this plant are used in traditional remedies in the state of Bahia, Brazil. The present work describes the leaf anatomy of I. asarifolia and characterizes the exudates of its secretory structures. The leaves have a unistratified epidermis composed of ordinary cells with straight to slightly sinuous anticlinal walls and thin cuticles. Paracytic stomata are found on both surfaces of the leaves at the same level as the ordinary epidermal cells. Trichomes producing polysaccharide secretions occur on the petiole and leaf blade and are considered colleters. The mesophyll is dorsiventral and the vascular bundle of the central vein is bicollateral. Two opposed nectaries occur on the petiole near the leaf blade. Each nectary is composed of a small canal with internal ramifications and numerous secretory trichomes. The laticiferous glands are articulated, not anastomosed, and are composed of large diameter cells with thin cell walls. The secretions of the laticiferous glands are lipidic.

Heterogeneity of epidermal cells in relation to nickel accumulation in hyperaccumulator plants belonging to the genus Alyssum L.

Epidermal cells of some plants are able to accumulate high levels of heavy metals (Zn, Ni, Cd). We studied this ability in plants in the genus Alyssum L. distinguished by tolerance to nickel (Ni). It was established that the predominant Ni accumulation occurred in epidermis, whereas in other tissues lower concentrations of the metal were revealed. It was also found that epidermal cells were characterized by heterogeneity in relation to Ni accumulation. The highest metal amount was accumulated in ordinary epidermal cells and in trichomes. Species-specific features of Ni distribution in leaf tissues in Alyssum spp. were shown. The reasons for the heterogeneity of epidermal cells in relation to Ni accumulation were discussed. We have attempted to resolve the contradictions encountered in the literature concerning the distribution and accumulation of Ni in the leaf tissues of plants belonging to the genus Alyssum L.

What is the influence of ordinary epidermal cells and stomata on the leaf plasticity of coffee plants grown under full-sun and shady conditions?

Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influence of these characteristics on stomata density, index, and sizes, in the total number of stomata, as well as the detailed distribution of stomata on a leaf blade. As a result, a highly significant positive correlation (R²(a) = 0.767 p ≤ 0.001) between stomatal index and stomatal density, and with ordinary epidermal cell density (R²(a) = 0.500 p ≤ 0.05), and a highly negative correlation between stomatal index and ordinary epidermal cell area (R²(a) = -0.571 p ≤ 0.001), were obtained. However in no instance was the correlation between stomatal index or stomatal density and stomatal dimensions taken into consideration. The study also indicated that in coffee, the stomatal index was 19.09% in shaded leaves and 20.08% in full-sun leaves. In this sense, variations in the stomatal index by irradiance, its causes and the consequences on plant physiology were discussed.

Variability in epidermal characters of Ginkgo tzagajanica Samylina (Ginkgoales) from the Paleocene of the Tsagayan formation (Amur Region) and the taxonomy of tertiary species of Ginkgo

The study of new material on Ginkgo tzagajanica Samylina and earlier published data has shown that the epidermal morphology of the species in highly variable; several new characters were found. Occurrence of different states of characters was analyzed, their frequency distribution was revealed, and typical and rare states of characters within variation rows were determined. The specific diagnosis of G. tzagajanica was emended. The most variable characters are degree of undulation of the anticlinal walls of cells of abaxial and adaxial epidermises (the latter is more variable) and degree of development and number of papillae on ordinary epidermal cells. Less variable characters are degree of development of papillae on subsidiary cells of stomata and how the papillae cover the stomatal apertures. These are characters that bear maximal diagnostic significance for Cenozoic Ginkgo.

Leaf anatomy of two Anemia Sw. species (Schizaeaceae-Pteridophyte) from a rocky outcrop in Niterói, Rio de Janeiro, Brazil

The ferns Anemia tomentosa (Sav.) Sw. var. anthriscifolia (Schrad.) Mickel and Anemia villosa Humb. & Bonpl. ex Willd. are widely associated with vegetation islands on rocky outcrops in Rio de Janeiro. Both species are desiccation tolerant. The leaf anatomy of these species was examined aiming to identify morphological characteristics that would allow the establishment of these species in water-scarce environments. The plants were harvested on Pedra de Itacoatiara and prepared according to the usual procedures. The petiole has a uniseriate epidermis with lignified cell walls, conical stegmata, and uniseriate multicelular and glandular trichomes. In A. villosa, the stomata protrude in a respiratory line. Under the epidermis the cells have thick, lignified walls. The parenchyma has phenolic compounds and starch grains. The petiole vascular bundles are surrounded by endodermis with Casparian strips and the xylem is V-shaped (A. villosa) or arc-shaped (A. tomentosa var. anthriscifolia). The leaf blades have a uniseriate epidermis with sinuous anticlinal and convex periclinal walls, conical stegmata and chloroplasts on both surfaces. The leaf margins of A. villosa have lignified cells. The guard cells of the stomata on the abaxial surface are on the same level or are raised above ordinary epidermal cells. Multicelular uniseriate trichomes and glandular hairs were observed. The dorsiventral mesophyll has loosely packed chlorenchyma with arm-shaped and H-shaped cells. The vascular bundles are surrounded by endodermis with Casparian strips and with parenchymatic extensions towards the epidermis. Anatomical results were analyzed considering the interaction of these plants with abiotic factors.

Adaptive evolution of secretory cell lines in vertebrate skin

AbstractThe embryonic horny layer of vertebrates contains distinctive cell lines that account for the remarkable, diverse secretory performances of their cutaneous apparatuses. Aquatic classes (jawless, cartilaginous and bony fishes) possess single gland cells, scattered among ordinary epidermal cells, that manufacture proteinaceous or mucous substances. This dichotomy is retained in adult amphibians, although the secretory cells in anamnionic tetrapode begin to be arranged in complex glands located in the loose dermis. In the Amniota, intensive keratinisation involving the epidermis results in the loss of the ancestral secretory lines, accompanied by the onset of a novel, lipid- producing gland type, which in mammals is flanked by the exclusive sweat gland apparatus.In this concise up-to-date review, we attempt to phylogenetically narrow the large variety of secretory structures in vertebrate skin into a few basic schemes, in the light of the close relationships between environmental challenges and ecolo...

Actin microfilament and microtubule distribution patterns in the expanding root ofArabidopsis thaliana

Determination of the precise role(s) of actin microfilaments in the control of cell shape and elongation in the root tips of the model genetic system Arabidopsis thaliana (L.) Heynh is frustrated by inadequate microscopy imaging techniques. In this paper, we documented both microfilaments and microtubules in the root tips of Arabidopsis by double immunofluorescence labelling and computer-generated reconstruction of confocal image series. Our procedure, which complements the use of recently developed fluorescent reporter proteins, revealed hitherto undescribed aspects of the Arabidopsis microfilament cytoskeleton that may provide important clues about mechanisms behind cell elongation. We found that preservation of extensive arrays of transverse cortical microfilaments depends on unperturbed microtubule organization. Compared with ordinary epidermal cells, cells situated in the trichoblast or hair-forming cell files were comparatively devoid of endoplasmic microfilaments when in the distal elongation zone, well before hair formation begins. Computer-aided reconstructions also revealed that the nonexpanding end walls of cells in the distal elongation zone have radially oriented microtubules and randomly arranged microfilaments. In dividing cells, microfilaments became more prominent in the cell cortex, and subtle differences between microtubule and microfilament organization were seen within the phragmoplast. These observations will form the basis of understanding the roles of the cytoskeleton in controlling elongation in root tissues. In light of the many Arabidopsis mutants with altered root morphology, our methods offer a reliable approach to assess the function of cytoskeletal proteins and signalling systems in root morphogenesis.Key words: actin microfilaments, Arabidopsis thaliana, distal elongation zone, microtubules, phragmoplast, roots.

Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H+‐ATPase in rhizodermal cells

ABSTRACTThe immunocytochemical localization of the plasma membrane H+‐ATPase in epidermal cells of tomato roots was studied using a monoclonal antibody raised against purified maize P‐type H+‐ATPase. Plants subjected to iron starvation exhibited increased proton extrusion that was confined to the root elongation zones. Immunogold labelling of the H+‐ATPase on the plasma membrane was considerably higher in rhizodermal cells within zones with intense proton extrusion than in non‐acidifying areas of the roots. Transfer cells were formed in rhizodermal cells of Fe‐deficient plants. Quantitative determination of immunolabelling revealed that the density of PM H+‐ATPase in transfer cells was about twice that of ordinary epidermal cells. In transfer cells, H+‐ATPase was most abundant on the plasma membrane lining the labyrinthine invaginations of the peripheral cell wall. While the number of immunologically detectable ATPase molecules in transfer cells was not spatially correlated with proton extrusion activity, the frequency of transfer cells was considerably higher in acidifying root areas relative to non‐active segments. Split‐root experiments indicated that both the steady‐state level of plasma membrane H+‐ATPase and proton extrusion activity are systemically regulated, indicating inter‐organ regulation of rhizosphere acidification. Exogenous application of the auxin analog 2,4‐dichlorophenoxyacetic acid and the ethylene precursor 1‐aminocyclopropane‐1‐carboxlic acid caused the formation of transfer cells at a frequency similar to that observed in Fe‐deficient roots. However, the number of proton pumps was not affected by the hormone treatment, suggesting that both responses are regulated independently. It is concluded that transfer cells in the rhizodermis may be important but not crucial for rhizosphere acidification.

Ultrastructural localization of photosynthetic and photorespiratory enzymes in epidermal, mesophyll, bundle sheath, and vascular bundle cells of the C4 dicot Amaranthus viridis.

In the leaves of the NAD-malic enzyme (NAD-ME)-type C4 dicot Amaranthus viridis L., there are chloroplasts in the vascular parenchyma cells (VPC), companion cells (CC), ordinary epidermal cells (EC), and guard cells (GC), as well as in the mesophyll cells (MC) and the bundle sheath cells (BSC). However, the chloroplasts of the VPC, CC, EC, and GC are smaller than those of the MC and BSC. In this study, the accumulation of photosynthetic and photorespiratory enzymes in these leaf cell types was investigated by immunogold labelling and electron microscopy. Strong labelling for phosphoenolpyruvate carboxylase was found in the MC cytosol. Weak labelling was observed in the CC and GC cytosol. Labelling for pyruvate, Pi dikinase occurred to varying degrees in the chloroplasts of all cell types except CC. Labelling for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase was detected in the chloroplasts of all cell types except MC. For both NAD-ME and the P-protein of glycine decarboxylase, intense labelling was found in the BSC mitochondria; weaker labelling was recognized in the VPC mitochondria. These data indicate that when not only the MC and BSC but also the other leaf cell types are included, the cell-specific expression of the enzymes in C4 leaves becomes more complex than has been known previously. These findings are discussed in relation to the metabolic function of epidermal and vascular bundle cells.

Sinuous ordinary epidermal cells: behind several patterns of waviness, a common morphogenetic mechanism.

Morphogenesis of sinuous epidermal cells in leaves of the fern Asplenium nidus and the monocotyledonous Cyperus papyrus, petals of the dicotyledonous Begonia lucerna. and in-vitro-grown leaves of the fern Adantum capillus-veneris is controlled by the local differentiation of their walls. In all these cases wall pads, including radial cellulose microfibrils, arc deposited at the junctions of the external periclinal wall with the anticlinal ones. Moreover, in Asplenium nidus, similar wall pads form at the junctions of the internal periclinal wall with the anticlinal ones. The wall pads are connected to anticlinal cellulose microfibril bundles running the whole depth of the anticlinal walls nr part of it. This wall differentiation imposes a highly controlled cell wall expansion, a consequence of which is the waviness of the epidermal cell anticlinal, walls. The pattern of wall reinforcement varies among different species, resulting in differences in the pattern of waviness. Cortical microtubule arrays mirror the orientated deposition of cellulose microfibrils in the epidermal Cells. These findings, derived from plants from different major groups, show a common epidermal cell morphogenetic mechanism depending on radial cellulose microfibrils and cellulose microfibril bundles. The facts that (a) epidermal cell morphogenesis in Adiantum copillus-veneris leaves grown in vitro differs considerably from that of typical leaves and (b) petal epidermal cells in Begonia lucerna are sinuous, while leaf epidermal cells are not, suggest that this mechanism may he affected by epigenetic factors.

Micromorphology of Johnsongrass (Sorghum halepense) Leaves

Adaxial and abaxial epidermal surfaces of johnsongrass leaves were studied to determine which cells contribute to leaf microroughness. Cork-silica cell (CSC) pairs, three types of prickles, macrohairs, bicellular trichomes, stomata, and ordinary short and long epidermal cells were found and described. CSC pairs made up about 22% of all cells and probably contribute more to microroughness than any other single type because each cork cell produces 11 ± 3 wax filaments that are up to 100 μm long. Bicellular trichomes represented 4 to 5% of the total cells but decreased leaf roughness by secreting a type of mucilage that covers microscopic wax crystals. Stomatal complexes comprised 15 to 18% of all cells and contributed to leaf roughness because they are slightly recessed below the leaf surface. Long prickles occur primarily over veins and represent less than 1% of all cells. Small prickles were present primarily on adaxial surfaces and represent only 3% of all cells. Macrohairs were the largest appendages, 237 ± 104 μm, but they represent far less than 1% of all cells and occur primarily over veins. Ordinary short cells comprised 6 to 13% of all cells. Long cells were most common (41%) of all cells. Short and long cells contribute to leaf roughness because the surface is often convex. A typical johnsongrass leaf may contain more than 25 million appendages on each surface that increase the roughness already caused by epicuticular wax crystals.

Observation of Merkel cells with scanning electron microscopy

This paper first elucidated the overall morphology of Merkel cells in the rat touch dome with scanning electron microscopy (SEM). Quinacrine-fluorescent Merkel cells in the touch dome were exposed by enzymatic treatment following application of dithiothreitol, photographed and then fixed. By referring to the photograph, the same fluorescent cells were easily identified under the SEM. Enzymatically isolated Merkel cells were also examined with SEM. Unlike quinacrine negative, ordinary epidermal cells, the Merkel cells had numerous finger-like processes, ranging from 0.1 to 0.25 μm in diameter and attaining to 2.5 μm in length.

Microtubules and morphogenesis in ordinary epidermal cells ofVigna sinensis leaves

Undifferentiated ordinary epidermal cells (ECs) ofVigna sinensis leaves possess straight anticlinal walls and cortical microtubules (Mts) scattered along them. At an early stage of EC differentiation cortical Mts adjacent to the above walls form bundles normal to the leaf plane, loosely interconnected through the cortical cytoplasm of the internal periclinal wall. At the upper ends of the Mt bundles, Mts fan out towards the external periclinal wall and form radial arrays. Mt bundles and radial arrays exhibit strict alternate disposition between neighbouring ECs. An identical reticulum of cellulose microfibril (CM) bundles is deposited outside the Mt bundles. Local wall pads rise at the junctions of anticlinal walls with the external periclinal one, where the CM bundles terminate. They display radial CMs fanning towards the external periclinal wall. The CM bundles and radial CM systems prevent local cell bulging, but allow it in the intervening wall areas. In particular, the radial CM systems dictate the pattern of EC waviness by favouring local tangential expansion of external periclinal wall. As a result, ECs obtain an undulate appearance. “Constrictions” in one EC correspond with protrusions of adjacent ECs. ECs affected by colchicine entirely lose their Mts and do not develop wavy walls, an observation substantiating the role of cortical Mts in EC morphogenesis.

An ultrastructural study on the origin of glomerulocytes, a type of blood cell in a styelid ascidian, Polyandrocarpa misakiensis.

The glomerulocyte is a type of blood cell in the compound ascidian, Polyandrocarpa misakiensis. It is a discoidal cell, measuring 12-13 μm in diameter and about 3 μm in thickness. The outer half of the cell is occupied by concentrically-arranged fibers, usually 0.2-0.3 μm thick; the nucleus and organelles are confined to the central cytoplasm. The ordinary epidermal cells are columnar and are characterized by an apical homogeneous cytoplasmic bulge, vesicular bodies in the cytoplasm, and juctions between them. Growing or immature glomerulocytes are found only in the epidermis. They have intracellular fibers and vesicular bodies, and there are juctions between them and epidermal cells. These facts strongly suggest the origin of the glomerulocyte from an epidermal cell. However, no definite statement can be made as yet because earliest stages of differentiation have not been observed. The glomerulocyte fully differentiated in the epidermis is apparently released into the hemocoel.

Ultrastructure of the Epidermis of Developing Cotton (Gossypium) Seeds: Suberin, Pits, Plasmodesmata, and Their Implication for Assimilate Transport into Cotton Fibers

The basal part of cotton fibers (Gossypium arboreum and G. hirsutum) was studied with light and electron microscopy in order to improve the understanding of assimilate transport into the fibers during the deposition of the cellulosic secondary wall. Although the distal parts of white cotton fibers are not suberized, a variable amount of suberin was found at the fiber base. This suberin is typically deposited in concentric layers, alternating with polysaccharides. Numerous pits occur in the base of cotton fibers and in ordinary epidermal cells in the periclinal and anticlinal walls. About 25% of the length of periclinal walls is occupied by pits, but only 2% of the anticlinal walls, being pitted mainly in their proximal part. In suberized walls the deposition of suberin is not reduced in the pit region. The pits, whether or not suberized, contain plasmodesmata (22 ± 2.3 and 27 ± 3.3 · μm−-2 in the periclinal and anticlinal walls of the white lint cultivar of G. hirsutum). Transport of assimilates into the fibers through the symplast is therefore possible. This transport may occur directly from mesophyll cells to fibers, or indirectly via ordinary epidermal cells. The minimum amount of assimilates transported into individual fibers during the phase of secondary wall deposition could be estimated (1.3 pg · fiber−-1 · sec−-1), as well as the corresponding symplastic flux of assimilates through the periclinal cell wall, neglecting a possible transport through the anticlinal walls (10−-3 pg · μm−-2 · sec−-1). It is postulated that in the green lint genotype of G. hirsutum and in wild cotton species (not studied in this paper), the uptake of assimilates into the fibers occurs through the symplast, the apoplastic pathway being excluded by the suberization of the fibers during secondary wall formation. Although cultivated, white-linted cotton species may use the same pathway, loading of assimilates from the apoplast is theoretically also possible, and the relative contribution of both pathways has to be determined experimentally.

ULTRASTRUCTURE OF THE EPIDERMIS OF DEVELOPING COTTON (GOSSYPIUM) SEEDS: SUBERIN, PITS, PLASMODESMATA, AND THEIR IMPLICATION FOR ASSIMILATE TRANSPORT INTO COTTON FIBERS

The basal part of cotton fibers (Gossypium arboreum and G. hirsutum) was studied with light and electron microscopy in order to improve the understanding of assimilate transport into the fibers during the deposition of the cellulosic secondary wall. Although the distal parts of white cotton fibers are not suberized, a variable amount of suberin was found at the fiber base. This suberin is typically deposited in concentric layers, alternating with polysaccharides. Numerous pits occur in the base of cotton fibers and in ordinary epidermal cells in the periclinal and anticlinal walls. About 25% of the length of periclinal walls is occupied by pits, but only 2% of the anticlinal walls, being pitted mainly in their proximal part. In suberized walls the deposition of suberin is not reduced in the pit region. The pits, whether or not suberized, contain plasmodesmata (22 ± 2.3 and 27 ± 3.3 · μm−‐2 in the periclinal and anticlinal walls of the white lint cultivar of G. hirsutum). Transport of assimilates into the fibers through the symplast is therefore possible. This transport may occur directly from mesophyll cells to fibers, or indirectly via ordinary epidermal cells. The minimum amount of assimilates transported into individual fibers during the phase of secondary wall deposition could be estimated (1.3 pg · fiber−‐1 · sec−‐1), as well as the corresponding symplastic flux of assimilates through the periclinal cell wall, neglecting a possible transport through the anticlinal walls (10−‐3 pg · μm−‐2 · sec−‐1). It is postulated that in the green lint genotype of G. hirsutum and in wild cotton species (not studied in this paper), the uptake of assimilates into the fibers occurs through the symplast, the apoplastic pathway being excluded by the suberization of the fibers during secondary wall formation. Although cultivated, white‐linted cotton species may use the same pathway, loading of assimilates from the apoplast is theoretically also possible, and the relative contribution of both pathways has to be determined experimentally.

A New Pinnate Cycad Leaf from the Upper Triassic Chinle Formation of Arizona

A recently discovered Upper Triassic leaf shows many of the characters of the leaves of the living cycads and is assigned to the Cycadales. The leaf, however, does not match any previously described fossil or living cycad leaf in all features and is assigned to a new genus and species, Aricycas paulae. The leaf bears oppositely arranged linear-lanceolate pinnae with pointed apices and contracted bases Pinnae contain prominent midribs and anastomosing lateral veins which end freely near the margins. The ordinary epidermal cells are rectangular with straight to slightly curving side walls and haplocheilic stomata. Pinnae in this leaf are apparently wrinkled and shriveled and in some cases fell before the parent leaves were shed, as is typical of the living cycads. It appears that this character has never been reported in fossil cycad leaves. Since A. paulae is Late Carnian age, it is one of the oldest known cycad leaves and thus supports the suggestion by Delevoryas (1982) that there is as much evidence that plants with compound leaves could have given rise to the Cycadales as plants with entire leaves have.