Primary Sculpture Research Articles

Taxonomic and ecological significance of seed morphology and ultrastructure in species of Lotus formerly classified in Dorycnium (Leguminosae – Loteae)

Seed morphology and ultrastructure of Lotus species from sections Dorycnium (L. dorycnium and L. graecus), Bonjeanea (L. rectus, L. hirsutusand L. strictus) and Lotus (L. corniculatus) have been studied using light and scanning electron microscopy. The seeds of studied species have a conservative structure typical for most Papilionoideae. Seed size, shape and color only partially allow distinguishing species in the studied group. The most morphologically distinguishable seeds are those of members of the polyphyletic section Bonjeanea, with L. rectus having the smallest and L. strictus the largest seeds. Seed size ranges in the species of the section Dorycnium overlap both between the members of the section and with seeds of L. hirsutus (section Bonjeanea). Seed surface ultrastructure around the hilum is very stable among studied species, whereas that on the lateral seed side is more variable. The types of surface sculpture on the lateral seed side do not strongly correlate with taxonomic position of species, but some correlations with eco-geographical patterns can be traced. The type of seed surface micromorphology with inconspicuous primary sculpture and thick secondary cuticular deposits was revealed in taxa, which distribution is connected with the Mediterranean region (L. hirsutus, L. dorycnium subsp. gracilis and partially L. rectus). Foveolate-papillose primary sculpture with thin secondary cuticular deposits is typical for species occurring in milder climate (L. corniculatus, L. strictus, L. graecus). Studied species can be subdivided into two groups by endosperm thickness. We believe that thin endosperm revealed in L. strictus and L. corniculatus may be a trait connected with the acceleration of development when spreading from the Mediterranean to the temperate climatic zone.

Seed morphology and post‐seminal development in Leiothrix Ruhland (Eriocaulaceae, Poales)

The genus Leiothrix (Eriocaulaceae) is restricted to South America, where most species occur in the Espinhaço mountain chain in Brazil. Seed ornamentation has a distinctive origin in the family and in most species of Leiothrix the seed coat has a striated pattern. The objective of this study was to evaluate the morphological aspects of seeds of Leiothrix as well as the post‐seminal development. Leiothrix seeds are elliptical or oval, the seed coat has a primary sculpture of isodiametric or hexagonal cells with concave periclinal walls and straight or sinuose anticlinal walls. Most species also have a secondary sculpture, which forms the striate ornamentation and this may be continuous or discontinuous with isolated, connected or cruciform annular striae. A comparative table of seed characters shows that most of them corroborate the current circumscription of the subgenera of Leiothrix. The seed coat striae expand with wetting and may help in seed imbibition during germination. Leiothrix seeds show a high germination rate and the post‐seminal development pattern is similar to that described for other species of Eriocaulaceae.

<p><strong>Morpho-anatomy of the cypselae of native species of Mutisieae (Asteraceae) from Mexico</strong></p>

The aims of this study were to describe and illustrate cypselae of 15 Mexican species of Mutisieae from observations using optical and scanning electron microscopy. The cypselae are heteromorphic with pilose, sericeous or glandular indumentum. The primary sculpture of the surface has two microstructural patterns: reticulate and plicate. The secondary sculpture is striate in 13 taxa, but in two species, Chaptalia estribensis and C. mexicana, differences were found in the secondary sculpture of the external and internal cypselae. The most distinctive anatomical trait is in the epicarp, which has rectangular or square-shaped cells that have a convex periclinal wall in most species of Chaptalia. The mesocarp has vascular bundles with fibers in all species of Chaptalia, but fibers are absent in Adenocaulon, Gerbera and Leibnitzia. In addition, the cells of the mesocarp inner layer have either thick walls or only an anticlinal wall in nine species of Chaptalia. The micromorphological characteristics of the primary or secondary sculpture of the surface, the type of trichomes and the variation they present have taxonomical value for recognizing closely-related taxa, whereas anatomical traits of the mesocarp distinguish Adenocaulon, Gerbera and Leibnitzia from most Chaptalia species.

УЛЬТРАСКУЛЬПТУРА ЕРЕМІВ ПРЕДСТАВНИКІВ РОДУ ISODON (SCHRAD. EX BENTH.) SPACH (LAMIACEAE LINDL.)

The studied was ultrasculpture of seed surface of 2 representatives of the genus Isodon (Schrad. ex Benth.) Spach from the family LamiaceaeLindl.– I. japonicus (Burman) H. Hara and I. japonicus (N. Z. Burm) Hara var. glaucocalyx (Maxim.) H. W. Li, introduced in the M. M. Gryshko National Botanical Garden National Academy of Sciences of Ukraine (Right-bank Forest-steppe). Representatives of the genus are common in the Asian region with the greatest species diversity in China; 2 species are found in the tropical regions of Africa. Screening of literary foreign sources showed that microscopic studies of the seeds of the species and variate did not occur, at least we did not find any information on this issue. This prompted us to investigate the macro- and micromorphology of the seeds. SEM was used in the work. Methodically guided by the well-known work of W. Barthlott. The descriptive part is documented photographically. As a result of the experiment, features in morphology and structure, common and distinctive features of seeds, morphological descriptions of their shape, color, primary and secondary sculpture of spermoderm are revealed. It has been established different types of external relief for species and the variete: for I. japonicus, a characteristic densely hilly relief, and for I. japonicus var. glaucocalyx– irregularly-mesh.Also revealed differences in the structure of the outer periclinal and anticlinal walls. The outer periclinal walls of the species are convex, anticlinal concave, and in the variate– concave and protruding respectively. The spermoderm of the seeds I. japonicus var. glaucocalyx is characterize by the presence of various types of papillomas in the apical region and stomatal cells, the significance and function of which still need to be further investigated. Differences in the microrelief of the seeds can be used as auxiliary diagnostic features at the species taxonomic level for plants of the genus Isodon, obtained under conditions of introduction from the seeds of the Index Seminum system.

The morpho-anatomy of cypselae in subtribe Leiboldiinae (Vernonieae, Asteraceae)

Surface and some anatomical characteristics of mature cypselae in four genera and 12 species members of the subtribe Leiboldiinae were analyzed, through light and scanning electron microscopy, with the aims of testing their diagnostic value in the taxonomical delimitation, and for this reason also studied related genera of Vernonieae which corresponds to 13 genera and 15 species grouped in seven subtribes. In addition to performing a detailed description of cypselae surface and anatomical characteristics, their potential taxonomical value is discussed. Most Leiboldiinae have prismatic cypselae, but when combined with the number of ribs and surface characteristics, species or genera can be identified. For example, Stramentopappus has obovate glabrous cypselae without a carpopodium compared with the other members of this subtribe. Bolanosa has a sericeous glandular indumentum, and Leiboldia has glands at the base of the cypselae and reticulate primary sculpture. The species of Leiboldiinae and other subtribes of Vernonieae here studied with crystals have prismatic ones contrary to the ones previously described for the Neotropical Vernonieae that were considered raphides.

Seed characteristics of Withania somnifera (Solanaceae)

The seed characteristics of Withania somnifera were studied using light and scanning electron microscopy in order to determine the specific features of this species. The seed color is yellow, and the seed shape is reniform measuring between two to three millimeters. The seed of W. somnifera is exarillate and albuminous. The seed coat type is exotestal. The seed coat develops from a single integument. The young seed coat consists of single-layered exotesta, multi-layered mesotesta and single-layered endotesta. However, parenchymatous mesotesta layers are completely compressed at maturity. Therefore, the seed coat was represented by sclerenchymatous exotesta. The primary sculpture on the seed surface is reticulate, and cells are irregular in shape with undulating anticlinal walls. In addition, the seed surface has several characteristic holes between the anticlinal walls.

Seed morphology and systematics of the European species of Erica L. sect. Gypsocallis Salisb. (Ericaceae)

The European heathers Erica manipuliflora, Erica multiflora and Erica vagans (sect. Gypsocallis) are related species characterized by a glabrous ovary, exerted, muticous anthers and a pale pink, urceolate corolla. The existence of three species is the most accepted treatment for this group, but there are uncertainties about this taxonomic interpretation. In this article, we used seed morphological characters to assess the systematics of the group. Seeds were studied by means of scanning electron microscopy techniques. E. multiflora has a distinct seed type, 1–1.5 mm long, flattened, yellowish with a striate-reticulate primary sculpture. E. vagans and E. manipuliflora have smaller seeds, brown with a reticulate pattern. Seeds of E. vagans are globose, 0.5 mm wide, while E. manipuliflora has mostly ellipsoid seeds 0.7 mm long. However, seeds of E. manipuliflora from the Adriatic coasts are closer to those of E. vagans, and this may support the existence of E. manipuliflora subsp. anthura.

Development and morphology of the gynoecium and nutlet in two South-American Bulbostylis (Cyperaceae) species

The anatomy and ontogeny of the gynoecium and nutlets of two Bulbostylis species with different micro-morphology, Bulbostylis capillaris sensu Barros and B. major, were analyzed. The specific aim of this work was to identify which part of the pericarp determines the differences in the nutlet surface between these two species. We found that pre-fertilization development is the same in both species, with differences between species appearing only after fertilization. In the nutlet of B. major, the exocarp forms a tuberculate primary sculpture that has nipple-like protuberances consisting of one conoidal silica body per cell, whereas the secondary sculpture is micro-granulose and is constituted by the cuticle. In the nutlet of B. capillaris, the primary sculpture is granulose and is formed by the presence of starch granules in the exocarp that do not degrade, whereas the secondary sculpture is smooth.

Variation in seed morphology in the genus Erica L. (Ericaceae)

Variation in seed morphology in the genus Erica L. (Ericaceae) Seed morphology was studied in 136 species of Erica, including 123 from South Africa (Cape Floristic Region), 5 from tropical Africa, and 8 from Europe. Seed anatomy was studied in 13 selected species by light and scanning electron microscopy. Seed morphology of each species was described and documented by SEM micrographs. Ten major diagnostic features were selected, concerning seed shape, primary sculpture, and fine relief. On the basis of these features, the species were divided into 14 groups. Within them, 40 morphologically homogeneous subgroups were distinguished, which could possibly be used in future revisions of the genus. A key to species identification has been developed on the basis of seed characteristics. A very close similarity was observed between seeds of some Erica species from distant parts of the distribution range of this genus.

Testa sculpture in the genus Frailea (Cactaceae)

The primary sculpture of the seed surface in the genus Frailea (Cactaceae) is characterized by a ± flat outer periclinal wall and the presence of an usually eccentric papilla. Papilla morphology differs mainly in size and breadth:length ratio. Seeds of different species (groups) are characterized by special patterns in the arrangement of short and long papillae on the surface, thus providing a useful tool for taxonomic studies in Frailea. The seeds of Frailea castanea possess branched papillae, a character restricted in this genus to this species. Moreover, such papilla morphology seems to be unique for the seed epidermis in spermatophytes. The possible function of the papillae is discussed.

Testa sculpture in the genus Frailea (Cactaceae)

The primary sculpture of the seed surface in the genus Frailea (Cactaceae) is characterized by a ± flat outer periclinal wall and the presence of an usually eccentric papilla. Papilla morphology differs mainly in size and breadth:length ratio. Seeds of different species (groups) are characterized by special patterns in the arrangement of short and long papillae on the surface, thus providing a useful tool for taxonomic studies in Frailea. The seeds of Frailea castanea possess branched papillae, a character restricted in this genus to this species. Moreover, such papilla morphology seems to be unique for the seed epidermis in spermatophytes. The possible function of the papillae is discussed.

Systematic significance of fruit morphology and anatomy in tribes Persicarieae and Polygoneae (Polygonaceae)

Fruits of Polygonaceae have a basically similar construction of indehiscent nuts or achenes. Sections of fruits, coupled with surface patterns were studied with SEM and LM in all genera of the tribes Persicarieae and Polygoneae (Polygonoideae-Polygonaceae). The outer layer of the pericarp is usually thickened and its anatomy can be used consistently to delimit genera more than any other character of the fruit. Cells are most often puzzle piece-shaped in surface view, but the shape of the cells may become polygonal with straight anticlinal walls towards the endocarp. The primary sculpture of the cells is highly variable and has value at the specific level, rarely at the generic level. No strict correlation exists between the external surface patterns and the anatomy. Two main cell types can be recognized in cross- and longitudinal section, correlated with the straight or undulating outline of the anticlinal walls. No distinction can be made between sections Persicaria, Tovara, Echinocaulon, and Cephalophilon of the genus Persicaria; all share narrow rectangular cells with undulating anticlinal walls. Aconogonon and Bistorta can be delimited by the square to rectangular cells with a narrow dichotomously branching lumen and straight anticlinal walls; both genera are best grouped as a single genus with two sections. A similar arrangement is found occasionally in species of Polygonum s.sPolygonella, Atraphaxis, Fallopia and Calligonum . Fruit anatomy of Pteropyrum is distinctive. The genus Polygonum s.s. shows a wide range of integrating patterns, ranging from straight to undulating anticlinal walls and cannot be separated from Polygonella. Fagopyrum is aberrant in having a parenchymatic exocarp and a thickened mesocarp; other evidence supports its isolated position. Different fruit anatomical patterns have arisen several times in evolution and have a limited value at tribal level but are useful at generic level. It is suggested that an arrangement with straight anticlinal walls and a broad lumen, eventually with dendricular branching towards the periphery, is ancestral.

Systematic significance of fruit morphology and anatomy in tribes Persicarieae and Polygoneae (Polygonaceae)

Fruits of Polygonaceae have a basically similar construction of indehiscent nuts or achenes. Sections of fruits, coupled with surface patterns were studied with SEM and LM in all genera of the tribes Persicarieae and Polygoneae (Polygonoideae-Polygonaceae). The outer layer of the pericarp is usually thickened and its anatomy can be used consistently to delimit genera more than any other character of the fruit. Cells are most often puzzle piece-shaped in surface view, but the shape of the cells may become polygonal with straight anticlinal walls towards the endocarp. The primary sculpture of the cells is highly variable and has value at the specific level, rarely at the generic level. No strict correlation exists between the external surface patterns and the anatomy. Two main cell types can be recognized in cross- and longitudinal section, correlated with the straight or undulating outline of the anticlinal walls. No distinction can be made between sections Persicaria, Tovara, Echinocaulon, and Cephalophilon of the genus Persicaria; all share narrow rectangular cells with undulating anticlinal walls. Aconogonon and Bistorta can be delimited by the square to rectangular cells with a narrow dichotomously branching lumen and straight anticlinal walls; both genera are best grouped as a single genus with two sections. A similar arrangement is found occasionally in species of Polygonum s.sPolygonella, Atraphaxis, Fallopia andCalligonum . Fruit anatomy of Pteropyrum is distinctive. The genus Polygonum s.s. shows a wide range of integrating patterns, ranging from straight to undulating anticlinal walls and cannot be separated from Polygonella. Fagopyrum is aberrant in having a parenchymatic exocarp and a thickened mesocarp; other evidence supports its isolated position. Different fruit anatomical patterns have arisen several times in evolution and have a limited value at tribal level but are useful at generic level. It is suggested that an arrangement with straight anticlinal walls and a broad lumen, eventually with dendricular branching towards the periphery, is ancestral.

Seed Morphology of Hydrangeaceae and Its Phylogenetic Implications

Seed morphology of Hydrangeaceae was explored to describe the parameters of diversity, define characters and character states, and hypothesize monophyletic groups in the family on the basis of derived features. Eleven seed characters were defined that delimit four basic aspects of morphology, including (1) shape, (2) primary sculpture, (3) secondary sculpture, and (4) appendages. Character states could not be delimited readily in some aspects of diversity, including transectional shape and length of seeds. Despite continuous variation in seed length, when mapped on previous cladograms these data supported the hypothesis that seeds less than 1.0 mm long were plesiomorphic and that seed size had increased separately in different subclades. Seed size increased in association with wing loss in Fendlera, Fendlerella, and Whipplea. A shift from apical, interstylar dehiscence of fruits that produce a very limited gap for seed emergence in most members of the hydrangea clade to fruit wall fragmentation may have p...

The diversity of micromorphological features in the genus Coccoloba (Polygonaceae)

Coccoloba P. Browne ex is a large and taxonomically complex genus of woody neotropical Polygonaceae. In this study, which includes 70 taxa, leaf and perianth epiderms and pollen surfaces were studied by scanning electron microscopy (SEM). Stomata, primary sculpture, epicuticular wax deposits, and multicellular glandular hairs of leaf blades together with secondary sculpture of perianth epiderms constitute taxonomically important micromorphological characters. Pollen morphology of the examined species is relatively uniform. Types based on surface ornamentation vary continuously from finely punctate‐striate to deeply punctate‐striate or microreticulate. Two species, C. acapulcensis and C. cordata, differ markedly from the rest of the investigated species by having spinulose ektexines. The diagnostic‐descriptive value of the characters studied is more pronounced than the taxonomic‐phylogenetic value. The disjunct distributions of two closely related species pairs C. acapulcencis/C. cordata and C. brasiliensis/C. schomburgkii are discussed.

Epidermal and seed surface characters of plants: systematic applicability and some evolutionary aspects

Based on SEM examinations of about 5000 species of seed plants, this is a survey of their epidermal surface characters with an aim to application in taxonomy. Surface characters may be grouped into four categories: (1) Cellular arrangement or cellular pattern. (2) Shape of cells (the “primary sculpture” of a surface). (3) Relief of outer cell walls (the “secondary sculpture” superimposed on the primary sculpture), caused mainly by cuticular striations and superficially visible wall inclusions and wall thickenings. (4) Epicuticular secretions (the “tertiary sculpture” superimposed on the secondary sculpture), i.e. mainly waxes and related substances.The systematic applicability is discussed for each of these structural groups. Epidermal characters are only slightly influenced by environmental conditions. Their high structural diversity provides most valuable criteria for the classification between species and family level. There is also some evidence for their systematic applicability above the family level.The possible evolutionary–ecological significance of surface sculpturing is discussed briefly. There is evidence that these features may be seen primarily under the aspects of reduced ability of plants to contaminate and as temperature control mechanisms of the surfaces.