Pericarp Anatomy Research Articles

A New Pattern of Phytomelanin Deposition in Cypselae of Bahieae (Asteraceae, Heliantheae Alliance)

ABSTRACTPhytomelanin is the dark and highly inert substance found in the fruit walls of the Heliantheae alliance clade within Asteroideae (Asteraceae). Phytomelanin deposition pattern in the cypselar wall was studied in two taxa of the Bahieae—Bahia pedata A. Gray and Palafoxia arida B. L. Turner. The pericarp anatomy studies have revealed that the phytomelanin deposits in the schizogenous space between the hypodermis and fiber layer. Our findings reveal that phytomelanin deposition is associated with fiber and has also brought out a new pattern of phytomelanin deposition between inner (fibrous zone) and outer sclerified layers (hypodermal) in the schizogenous space. The study recorded a first‐time report of a second layer of phytomelanin outer to the sclerified hypodermal cells at maturity. Our observations point to phytomelanin precursors being synthesized as pliable fluid substances associated with fiber cells and solidifies later in the intercellular space. The study also recorded the first report for the occurrence of tracheoidal cells in the pericarp wall of the Bahieae within the Heliantheae alliance. Our study has provided insights to decipher evolutionary patterns and the significance of phytomelanin in the phytomelanic fruit clade (PFC), and it could help to resolve long‐standing debates on deposition patterns and the site of synthesis of phytomelanin.

Trends of fruit morphogenesis in Pandanaceae: comparative carpology of Freycinetia Gaudich

Abstract With the current reassessment of the phylogeny of Pandanales, revealing the peculiarities of fruit structure of representatives of the order, as well as determination of apomorphies and plesiomorphies of the families included in the order are of importance. With the aim to fill in gaps in the data on fruit structure and to determine principal trends of fruit morphogenesis in Pandanaceae, the present study focused on pericarp anatomy in the genus Freycinetia, fruits of which are traditionally referred to as berries. The present investigation confirmed the lack of a continuous sclerenchymatous zone in the pericarp of Freycinetia species, and the fruit is treated as a superior paracarpous berry of Nuphar type. Fusiform groups of longitudinally elongated sclereids are revealed in the mesocarp of Freycinetia palawanensis (incertae sedis) and F. graminifolia (section Solmsiella). Since this character is treated as specific for the subgenus Gaudichaudiella, the inclusion of these two studied species in this subgenus is proposed. The principal carpological plesiomorphies and apomorphies of the family are outlined, and two scenarios for fruit morphogenesis, from berries to ‘drupaceous’ fruits and vice versa, are proposed.

Revisiting the pericarp as a barrier restricting water entry/loss from cotyledons and embryonic axis of temperate desiccation-sensitive Quercus acorns.

Fully mature acorns of Quercus variabilis, Q. aliena, Q. mongolica, and Q. glandulifera are desiccation-sensitive. X-ray computer tomography showed that cotyledons shrink during drying, but embryos are protected. Information available on recalcitrant acorns of tropical and sub-tropical species of Quercus suggests that an impermeable pericarp, which limits the entry and loss of water only through the hilum (scar), is the underlying mechanism that prevents drying of the embryo axis following dispersal until the germination season. However, there is a lack of consensus supporting this proposition across species, and it is not well understood if such mechanisms occur in temperate Quercus species. This study investigated the significance of the acorn pericarp for temperate oak species and presents an ecological framework based on the post-dispersal climatic conditions. Using Quercus variabilis, Q. aliena, Q. mongolica, and Q. glandulifera acorns, the relationship between moisture content (MC) and germination was established, and X-ray computed tomography (X-ray CT) was used to understand the internal structural changes of cotyledons and embryonic axis occurring during desiccation. Water entry and exit routes through the scar, pericarp and apex were determined by imbibition and drying experiments. Climatic data and acorn morphological characteristics and germination were subjected to a principal component analysis (PCA). Freshly dispersed acorns of all species had a moisture content (MC) above 35% fresh weight (FW) basis, but drying to 15-10% MC resulted in complete loss of viability, implying recalcitrance behaviour. X-ray CT images suggested that the pericarp offers some protection to cotyledons and embryonic axis during desiccation, but it is contingent on MC. Extensive drying to a low MC with the scar and apex covered with vaseline resulted in internal tissues shrinkage, corresponding with viability loss. Water could enter or exit through the pericarp, albeit at a much slower rate than through the scar. A combination of factors including acorn anatomy, moisture content at the time of dispersal, microhabitat, the position of acorns in the soil prevent embryo desiccation below the critical MC and thus promotes survival of acorns on/in the soil during winter in temperate regions. Pericarp anatomy, to some extent, prevents excessive drying of the embryonic axis by slowing water movement, but prolonged drying or predatory pressure could result in pericarp cracks, favouring the absorption of water during sporadic rain. In the latter case, the survival of acorns possibly depends extensively on the continuous erratic rainfall, i.e. continuous wet-dry cycle, but in-situ experiments are yet to be performed to test this hypothesis.

The systematic significance of pod morphological and anatomical variations in Indian Crotalaria L. (Leguminosae)

Pod morphological and anatomical variations of Indian Crotalaria were evaluated to understand the systematic significance and dispersal mechanisms. Pods show variation between species with respect to size, colour, persistence of calyx, presence of trichomes and number of seeds per pod. Pods with length less than 1.5 cm have thicker endocarp when compared to the combined thickness of exocarp+mesocarp (exception being C. berteroana). These pods are likely indehiscent and are dispersed as a unit (enclosing the seeds). On the other hand, pods 1.5 cm or longer have thicker exocarp+mesocarp with respect to the endocarp. These pods dehisce and disperse seeds by explosive mechanism. Seed dispersal is assisted by the sclerenchymatous zone. The angular arrangement of sclereids in opposite directions in the two halves of the narrow fruit enables spiralization soon after explosion of the pods. The orientation of the fibres in the endocarp relative to the longitudinal axis of the fruit is the major factor determining dehiscence. Pericarp anatomy has been categorised into two major types, Type I: with the non-sclerenchymatous zone (exocarp+mesocarp) thicker than the sclerenchymatous zone (endocarp); and Type II: with the sclerenchymatous zone (endocarp) thicker than the non-sclerenchymatous zone (exocarp+mesocarp). The seemingly identical dispersal mechanism in the form of diaspore shows convergent evolution which occurs shows convergent evolution which occurs multiple times in different clades independently (viz., Calycinae and Crotalaria). C. pusilla and C. medicaginea pods possess air cavities, which may be an additional adaptation for diaspore dispersal.

Heterocarpy in Dipterocypselinae (Asteraceae): Morphology, anatomy and systematic significance

Heterocarpy occurs when a plant produces fruits of more than one distinct shape. This phenomenon may result in different dispersion, dormancy, and germination, enabling survival in diverse environmental conditions. Heterocarpy is common in Asteraceae, and one of its most extreme examples occurs in Heterocypsela H.Rob. However, the difference between outer and inner cypselae can be originated from its developmental stage. Even with doubts, heterocarpy is applied to circumscribe Heterocypsela, Allocephalus Bringel, J.N.Nakaj. & H.Rob., Dipterocypsela S.F.Blake, and Manyonia H. Rob. in the subtribe Dipterocypselinae S.C.Keeley & H.Rob. A recent phylogenetic study has also raised uncertainties about the Dipterocypselinae monophyly and, consequently, the importance of the heterocarpy and pericarp crystals in the subtribe circumscription. Thus, we reviewed the heterocarpy and its systematic significance in the Dipterocypselinae, using light microscopy and SEM techniques. Our results confirmed the heterocarpy in Heterocypsela, reaffirmed it in Allocephalus and Dipterocypsela, and refuted its loss hypothesis in Manyonia. However, the heterocarpy was not homologous between studied genera and should not be applied as a parameter to group them. The pericarp tissue organization of the studied species, including crystals, was similar to previously studied Vernonieae Cass., reaffirming the systematics significance of the pericarp anatomy at a tribal level. Gaps in the Vernonieae cypselae knowledge hampered the morphological approximation of Allocephalus gamolepsis from Lychnophorinae, and Heterocypsela from Chrestinae-Vernoniinae. However, the Vernonieae morphology comparison demonstrated fruitful, mainly to assess the systematic significance and evolutionary patterns of the cypselae tribe.

Fruit morphology and histology of Zostera asiatica Miki and Phyllospadix iwatensis Makino (Zosteraceae) in connection with сomparative carpologу of higher Alismatales

ABSTRACT The investigation of fruit morphology and pericarp anatomy of the genera Phyllospadix and Zostera from the Zosteraceae family enabled us to identify their fruit types based on fruit wall anatomical structure. Drupes of the Prunus type with lignified inner zone of the mesocarp and the endocarp are specific for Phyllospadix iwatensis, whereas in Zostera asiatica dorsally dehiscent follicles of the Myristica type lacking sclerenchyma in the pericarp are found. In addition, Zosteraceae pericarp structure was analyzed and compared with four other families of higher Alismatales: Potamogetonaceae s.l., Posidoniaceae, Ruppiaceae, and Cymodoceaceae. Their exocarp and mesocarp consisted of thin-walled cells and the endocarp comprised a single layer of sclerenchymatous cells. This type of pericarp differentiation is supposed to be the sуnapomorphy of terminal families of Alismatales. The fruits of Zostera and Phyllospadix have a more complex pericarp structure in comparison to the synapomorphic type of pericarp differentiation of higher Alismatales – in Phyllospadix iwatensis both the mesocarp and the endocarp are lignified, whereas in Zostera asiatica the sclerenchyma is lacking. The fruits of Zostera and Phyllospadix are treated as specialised types, and recognised as autapomorphic characters of Zosteraceae among higher Alismatales.

Comparative carpology of the genus Cardiocrinum (Endl.) Lindl. (Liliaceae)

The anatomy of pericarp of the mature fruit of Cardiocrinum cordatum (Thunb.) Makino was investigated.It was revealed, that the fruit of Cardiocrinum is a superior loculicidal capsule. The anatomy of its pericarp allow totreat the fruit as a transitional type of capsules between Lilium-type (the endocarp is lignified) and Galanthus-type (nolignification occurs in any zone of the pericarp). The peculiarities of pricarp structure of Cardiocrinum supports itstreatmend as a separate genus of the Liliaceae family.

Cytokinin treatment modifies litchi fruit pericarp anatomy leading to reduced susceptibility to post-harvest pericarp browning

Litchi (Litchi chinensis Sonn.) is a subtropical fruit known for its attractive red pericarp color, semi-translucent white aril and unique flavor and aroma. Rapid post-harvest pericarp browning strictly limits litchi fruit marketing. In the current research, we hypothesized that modification of litchi fruit pericarp anatomy by hormone application may reduce fruit susceptibility to post-harvest pericarp browning. In this context, we hypothesized that cytokinin treatment, known to induce cell division, may yield fruit with thicker pericarp and reduced susceptibility for fruit surface micro-crack formation, water loss and post-harvest pericarp browning. Exogenous cytokinin treatment was applied at different stages along the course of litchi fruit development and the effect on fruit pericarp anatomy, fruit maturation and postharvest pericarp browning was investigated. Interestingly, cytokinin treatment, applied 4 weeks after full female bloom (WFB), during the phase of pericarp cell division, led to mature fruit with thicker pericarp, reduced rate of post-harvest water loss and reduced susceptibility to post-harvest pericarp browning, as compared to non-treated control fruit. Histological sections ascribe the difference in pericarp anatomy to increased cell proliferation in the parenchymatic tissue and the highly-lignified brachysclereid cell layer. In contrast, exogenous cytokinin treatment applied 7 WFB, following the phase of pericarp cell division, significantly increased epidermal-cell proliferation but had no significant effect on overall fruit pericarp thickness and only minor affect on post-harvest water loss or pericarp browning. Interestingly, the late cytokinin treatment also significantly postponed fruit maturation-associated anthocyanin accumulation and chlorophyll degradation, as previously reported, but had no effect on other parameters of fruit maturation, like total soluble sugars and total titratable acids typically modified during aril maturation. In conclusion, exogenous cytokinin treatment at different stages in fruit development differentially modifies litchi fruit pericarp anatomy by induction of cell-type specific cell proliferation. Early cytokinin treatment during the phase of pericarp cell division may prolong litchi fruit storage by reducing fruit susceptibility to post-harvest water loss and pericarp browning.

Growth and histological development of the fruit pericarp in rambutan (Nephelium lappaceumLinn.)

Rambutan (Nephelium lappaceum Linn.), of the Sapindaceae family, is a fruit tree that grows in the humid tropics. After harvest, the fruit changes from bright red to dull brown in color and loses commercial value as the pericarp dehydrates. We studied the changes in the morphology and anatomy of pericarp during fruit development. The orchard from which the samples of rambutan fruits RI-148 were taken is located Tuxtla el Chico, Chiapas, Mexico, (lat. 14°58'N; long. 92°09'W; altitude 435 m), with an average annual temperature of 23°C, RH of 85% and 3,100 mm of rainfall. The results showed that the fruit had a sigmoidal pattern of growth, with an increase in total sugars in the aril from 8.7% on day 75 to 14.6% on day 95 after anthesis. The number of spinterns per fruit was constant (328±20), the number of stomata per spintern was about 3200 and about 1.0×106 fruit-1. The increase in length of the spinterns during development of the pericarp provides greater contact surface with the environment, which modifies the intensity of transpiration. Thickness of the pericarp cuticle halved from day 50 to day 100 after anthesis. Finally, the anomocytic stomata on the spinterns and pericarp, tended to stay open for the entire duration of fruit development, and consequently, the fruits experienced an acceleration in loss of moisture, dehydration, and color change (oxidation) during postharvest that shortened their shelf life.

Mummified fruits of Choerospondias nanningensis sp. nov. (Anacardiaceae) from the upper Oligocene of a low latitude site in East Asia

AbstractExtant species of Choerospondias (Anacardiaceae) are mainly distributed in the tropical and subtropical areas of East Asia. However, the fossil record indicates that the genus was more widespread in the past, with Cenozoic occurrences in both Europe and Asia. We investigated the pericarp anatomy of well‐preserved mummified fossil fruits of Choerospondias from the upper part of Yongning Formation (late Oligocene) of the Nanning Basin, South China. These fruits are recognized as a new species Choerospondias nanningensis sp. nov. This is the lowest latitude fossil occurrence for the genus, and the first fossil record of this genus from its modern area of distribution (South China), indicating that Choerospondias had spread into its modern area of distribution by the Oligocene. In this study, we also investigated the pericarp anatomical structure of the one extant species of Choerospondias. We found that this genus has an endocarp morphology and anatomy typical of the Spondioideae. This is the first study focusing on the pericarp anatomy of fossil and extant species of Choerospondias simultaneously. This study provides new fossil evidence for further understanding the phylogeny of this genus, and contributes significantly to the knowledge of fruit morphology of the family Anacardiaceae.

The role of domestication and maternal effects on seed traits of crop–wild sunflower hybrids (Helianthus annuus)

AbstractHybridisation between crops and their wild relatives may promote the evolution of weeds. Seed germination and dormancy are the earliest life‐history traits and are highly influenced by the maternal parent. However, the ecological role of the maternal effect on seed traits in the evolution of crop–wild hybrids has received little attention. In this study, we test the relative importance of maternal and hybridisation effects on seed traits of the first generation of crop–wild sunflower hybrids (Helianthus annuus). Seed germination was tested in two wild populations with contrasting dormancy, two cultivated materials and their reciprocal crosses at four different times after harvest and three different temperatures. Seed germination at each of the four times, after ripening response and secondary dormancy were recorded along with four morphological traits. Additionally, the pericarp anatomy was analysed with light and scanning electron microscopy. We observed strong maternal effects on all seed traits. Seed germination, morphology and pericarp anatomy differed largely between the crop and wild seeds and these traits in the crop–wild hybrids resembled their female parent. Slight but significant hybridisation effects were observed in germination, mainly in seeds produced on wild plants. Crop hybridisation changed seed germination, the after ripening response and secondary dormancy in the crop direction. Morphological and anatomical traits associated with domestication strongly correlated with the observed differences in seed germination and dormancy in crop–wild sunflower hybrids. The large maternal effects along with the evolutionary divergence in seed traits were responsible for the large phenotypic differences observed in crop–wild hybrids with the same genetic composition. Wild‐like seed traits of hybrids suggest that there are no barriers to crop gene introgression at the seed level whereas crop‐like seed traits could be strongly selected against, conditioning the selection of traits expressed later in the life cycle and in the next generations.

Differences in the fruit structure and the location and content of bioactive substances in Viburnum opulus and Viburnum lantana fruits

Many Viburnum species are popular ornamental shrubs and, simultaneously, highly valued medicinal plants as a source of many bioactive compounds, including antioxidants. Viburnum bark, flowers, and fruits are widely used in traditional and folk medicine, and the fruits of some species are used as cooking ingredients. The knowledge of the microstructure of Viburnum fruits and the accumulation sites of bioactive substances in these organs is rather poor. Comparative analyses of the microstructure of ripe Viburnum opulus and Viburnum lantana drupes were carried out using light, scanning, and transmission electron microscopes. The location of various groups of metabolites in the fruits of both species was determined with the use of histochemical tests and fluorescence microscopy. Additionally, the major antioxidants, i.e. carotenoids, polyphenols, and flavonoids, were quantified and a number of morphometric traits of the drupes were presented. The V. opulus and V. lantana fruits were found to differ in some morphological traits and in many characteristics of the pericarp anatomy and ultrastructure. It was shown that the Viburnum fruits contained lipids and lipid compounds (carotenoids, essential oils, steroids, and saponins), polyphenols (tannins, flavonoids, and anthocyanins), pectins, and proteins. The fruits of V. opulus contained greater quantities of carotenoids, polyphenols, flavonoids, steroids, and pectins than the V. lantana drupes, whereas the latter were characterised by higher contents of essential oils, saponins, and proteins. The metabolites were located in different pericarp layers, but the greatest amounts were identified in the drupe skin.

Evaluation of Mineral Profile, Texture, Sensory and Structural Characteristics of Old Pepper Landraces

Old traditional Serbian pepper landraces (Nizača, Lokošnička and Turšijara), grown in South Serbia and produced by seed sowing or transplanting, were evaluated in this study. Besides the basic morphological properties and composition, the features characterizing fruit color and pericarp anatomy were determined in order to analyze and systematize the traits relevant from the aspect of traditional end use of examined landraces. Landraces Lokošnička and Nizača, characterized with higher force needed to puncture fruit skin, larger number of mesocarp layers, thicker endocarp and thicker collenchyma tissue, followed with higher total soluble solids content are more suitable for intended traditional use than Turšijara. Production from transplants should be favored in order to obtain more uniform, darker red fruit color, ASTA value, higher TSS content as well as higher yields. There are genetic differences of the some quality differences between the cultivars. Lokošnička has higher mesocarp layers, thicker endocarp and collenchyma tissue. Practical Applications Pepper fruits dried in traditional way slowly in a draught are used in preparation of local ethno-gastronomic specialities, with special position in local customs related to dietary habits during the spring Orthodox fasting period. Intact fruit skin is also the prerequisite for successful utilization in traditional culinary specialties-stuffed dry pepper fruits previously soaked in water that remain whole during cooking and baking. Structure and texture of pepper fruit skin and pericarp can consequently be considered as one of the key aspects of technological quality of pepper based on which landraces were selected for described traditional preservation technique. The research for answers to this technological challenge was the motivation of this study, which evaluated the impact of different predrying process (type of landraces, production methods) on qualities of pepper fruit. The data shown would provide scientific rationales for obtaining high-quality whole fruit pepper as material for stuffing.

Pericarp anatomy and hormone profiles of cypselas in dormant and non-dormant inbred sunflower lines.

The pericarp anatomy and the effects of storage after harvest, storage temperature and early cypsela imbibition on phytohormone profiles were studied in inbred sunflower lines B123 and B91. On day 0, germination of B123 cypselas was near 0%, indicating dormancy, whereas that of B91 cypselas was near 100%, indicating non-dormancy. The germination of B123 and B91 on day 33 at room temperature (25°C) storage was similar. Cell wall thickness and sclerification of the pericarp were higher in B123 than B91, suggesting that structural characteristics may contribute to physical dormancy in B123. Jasmonates (JAs), salicylic acid (SA) and abscisic acid (ABA) were measured in dry and imbibed pericarps. SA content of dry pericarp was higher on day 33 than day 0. SA content during imbibition on day 33 was similar for room and low (-20°C) storage temperatures. ABA content after 12h imbibition was similar on days 0 and 33 at low temperature, but it increased on day 33 at room temperature for B123. 12-Oxo-phytodienoic acid (OPDA) was maximal on day 0 for B123, but peaked at day 33 at low temperature for B91. JA was higher on days 0 and 33 at room temperature as compared with low temperature. Our findings indicate that pericarp hormone profiles are affected in the two lines with different dormancy degree depending on storage conditions and imbibition processes.

Centuries-Old Viable Fruit of Sacred Lotus Nelumbo nucifera Gaertn var. China Antique

During the Sino-Japanese conflict of the 1920s, Japanese botanist Ichiro Ohga was presented single-seeded fruit of Nelumbo nucifera var. China Antique collected by a local farmer from a dry lakebed in Northeast China (then, “Manchuria”). Ohga studied the fruit and published his findings. Years later, we tested the germination of Nelumbo fruit from the same locality. The oldest seed sprouted, having a germination time of ~3 days, was radiocarbon dated to be ~1300 years old. These cold- and drought-tolerant seeds exhibited shoot-before-root emergence and a primary green plumule capable of “dim-light” photosynthesis. Such traits and the notable long-term viability of the fruit spurred the interest of Ray Ming, University of Illinois that has now led to the sequencing of the Nelumbo genome. Analyses of this genome may provide insight into the biochemistry of Nelumbo on wax-biosynthesis genes, and application of aging-related thermostable proteins to the extension of seed-life and improvement of food quality of economic crops. Here, we review the history of these long-lived Nelumbo fruit, and their occurrence, discovery, collection, propagation, and methods of seedling care. The robust impermeable wax- and suberin-covered pericarp is a major factor contributing to their remarkable longevity. New findings are presented on the modern and 459- and 464-year-old pericarp anatomy, impermeability to water, and whole fruit and pericarp mechanical properties, and comparison of the mode of fruit weight-gain during imbibition and germination time relative to fruit maturity.

Fruit structure in Magnoliaceae s.l. and Archaeanthus and their relationships

The family Magnoliaceae s.l. is a basal angiosperm family with two subfamilies-Magnolioideae and Liriodendroideae, which differ by the types and structure of their fruits and seeds. The late Albian genus Archaeanthus shares many features of its reproductive organs with Magnoliaceae s.l., but its pericarp anatomy was never studied in detail. A broad-scale carpological investigation of Archaeanthus and Magnoliaceae s.l. was undertaken to reveal the nature of the similarities in fruit structure and to reconstruct Archaeanthus pericarp anatomy. These data are important to determine the early stages of fruit morphogenesis and thus to clarify relationships of Archaeanthus to the taxa of Magnoliaceae s.l. The pericarp anatomy was studied with light microscopy, SEM, and polarizing microscopy. The dehiscent, polyspermous follicles shed from the receptacle of Archaeanthus share similarities with dehiscent follicles of Magnoliaceae s.s. and shedding nutlets of Liriodendron. The seeds of Archaeanthus are dorsiventrally flattened, ovoid, and encircled with a single circular wing. The pericarps of all the taxa studied are differentiated into exocarp (epidermis), multilayered mesocarp, and endocarp (fiber-like sclereids). The mesocarp consists of parenchyma with scattered secretory cells and sclereid clusters (Magnoliaceae s.s., Archaeanthus) or composed by sclerenchyma (Liriodendron). The specializations of dehiscent multifollicles of unknown Cretaceous ancestors for different modes of seed and fruitlet dispersal formed the basis for the differentiation of two evolutionary lines with their divergence occurring more than 100 million years ago: Magnoliaceae s.s. and the Archaeanthus-Liriodendroidea-Liriodendron line (Liriodendraceae s.l.) within the order Magnoliales.

The genus Bolboschoenus in Iran: taxonomy and distribution

A revision of the Iranian Bolboschoenus was made based on studies of herbarium material and cultivated plants. Fruit features (fruit shape and pericarp anatomy) were used as the main distinguishing characters; style branching, inflorescence structure and the colour of floral scales were considered as accompanying distinguishing characters. The following taxa were recognized: Bolboschoenus glaucus (Lam.) S. G. Sm., B. affinis (Roth) Drobov, B. schmidii (Raymond) Holub, B. planiculmis (F. Schmidt) T. V. Egorova and B. maritimus (L.) Palla. Taxonomical difficulties, especially in the B. affinis group and B. maritimus are discussed. Bolboschoenus glaucus was found in all of the phytogeographical regions of Iran, and it is more frequent than any other Bolboschoenus species. Bolboschoenus planiculmis is very rare in the Irano–Turanian and Hyrcanian regions and grows only in human‐influenced habitats; it might be introduced as a weed in rice fields. Bolboschoenus maritimus, B. affinis and B. schmidii occur in the Irano–Turanian region only rarely. Bolboschoenus maritimus reaches the southeastern border of its distribution area in this region. All these species typically grow at higher altitudes. Great morphological variability in inflorescence structure was found in some species (especially in B. glaucus), which may be partly explained as a response to habitat conditions and partly by genotypic diversity.

Pericarp anatomy of wild roses ( Rosa L., Rosaceae)

The pericarp anatomy of representatives of all subgenera and sections of the genus Rosa was studied. All species have the same basic pericarp structure: it is composed of inner and outer endocarps, mesocarp and exocarp formed by the epidermis and hypodermis. The differences concern mainly the thickness of particular layers, and the shape and size of their cells. Cells of the endocarp and mesocarp are thick-walled. The only exception is Rosa rugosa mesocarp, which is composed of rather thin-walled cells with a large lumen. The endocarp structure of Rosa achenes resembles the drupe of the genus Prunus s.l. and drupelets of Rubus species.

Morfoanatomia e ontogênese do pericarpo de Manihot caerulescens Pohl e M. tripartita Müll. Arg. (Euphorbiaceae)

Manihot caerulescens and M. tripartita are shrub species of cerrado, known as mandioca-brava. Works on structure of pericarp of Euphorbiaceae are rare and many of the found morphologic descriptions present dubious interpretations, especially on the dehiscence. The present work aimed to describe the morphology, anatomy and ontogeny of pericarp of the two species of Manihot, comparing themselves and relating structural aspects of pericarp to the dehiscence. We verified that the pericarp follow four developmental periods, as typical of dry fruits. Two meristems are formed: a subadaxial, that produces the inner mesocarp; and another adaxial, that forms the endocarp, homogeneous and collenchymatous in M. caerulescens, and heterogeneous in M. tripartita, with outer gelatinous fiber-sclereids and an collenchymatous inner portion. We observed the formation of separation tissue, composed of loose parenchyma, in direction to the dorsal bundle of the three carpels and to the septa, which are more evident in M. tripartita. Finally, we verified variation in the sclerenchymatous stratum: in M. caerulescens, there is a layer of fiber-sclereids and one of stone cells, both of the mesocarp; in M. tripartita, these two mesocarpic layers occur, with bigger thickness, increased of the outer endocarp, also composed of fiber-sclereids. The fruits of both species are capsules which type depends on the development of separation tissue and of the dimension of sclerenchymatous stratum. Thus M. caerulescens presents indehiscent capsules, while M. tripartita forms septi-loculicidal capsules, since the dehiscence, even so passive, occurs in the dorsal regions and in the direction to septa.

Fruit structure and systematics of Monimiaceae s.s. (Laurales)

Fruit structure (anatomy) was studied in 27 species of 15 genera of Monimiaceae s.s . Almost all have apocarpous gynoecia, with the carpels more or less surrounded by a floral cup. The fruitlets are presented on the opened floral cup, which, depending on its pre- and post-floral development, differentially contributes to the attractive part of the mature fruit. Morphologically similar fruits may differ conspicuously in anatomical structure. Based on anatomical characters two different fruit forms were found: drupe(let)s (with compact sclerenchymatic endocarp forming a stone: putamen) and berry(let)s (with parenchymatic endocarp, and mesocarp parenchyma containing isolated sclereid nests). Four types of drupelets differing by the endocarp structure were tentatively distinguished: (1) the Monimia - type has a many-cell-layered putamen of large isodiametric sclereids, interrupted on the ventral side by few radial rows of small sclereids; (2) the Hortonia -type has a few-cell-layered putamen of isodiametric, especially thick-walled sclereids - it may be composed of two lateral halves, i.e. with the sclerenchyma partially interrupted on the ventral and dorsal sides (but without rows of small sclereids); (3) the Mollinedia -type has a few-cell-layered putamen, with more or less radially elongate sclereids with wavy cell walls; and (4) the Hedycarya -type has a one-cell-layered puta- men of pronouncedly radially elongate sclereids with wavy cell walls. Drupelets of some taxa with a single-cell- layered endocarp with only weakly thickened cell walls may represent a transition from drupelets to berrylets. The fruit structure supports three major clades recognized earlier by morphological studies and by molecular phylo- genetic analyses: (1) Monimioideae ( Monimia -type drupelets), (2) Hortonieae of Mollinedioideae ( Hortonia -type drupelets), and (3) the remainder of Mollinedioideae ( Hedycarya - and Mollinedia -types) and berrylets. Fruit structure also supports the close relationship of Monimiaceae and Lauraceae. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 265-285. ADDITIONAL KEYWORDS: berry(let) - comparative carpology - drupe(let) - fruit evolution - pericarp anatomy - phylogeny - putamen.