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  • 1
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    In:  Blumea - Biodiversity, Evolution and Biogeography of Plants (0006-5196) vol.20 (1972) nr.1 p.157
    Publication Date: 2015-03-06
    Description: Recently a review on the Angiosperm ovule has been published by the well-known Indian botanist V. Puri (1970). In this review the author stressed the differences between Angiospermous and Gymnospermous ovules, and he refused to accept their comparability or common descent. In this respect Puri comes close to Eames (1961). Both authors tend to regard the ovules as complex emergences. Apart from the main theme, there is a striking passage in this review dealing with the Hugo de Vries Laboratory at Amsterdam. According to Puri in that laboratory facts are sacrificed for hypotheses (p. 10). In the following we would like to start with the facts concerned and present them in a more convincing way, and then ask some simple questions on the structure of the ovules in order to show just how little precise information is available. This lack of information has had the effect of producing many different hypotheses. Boesewinkel and Bouman (1967) reinvestigated the initiation of the single integument in some Juglandaceous ovules. In a histogenetic study they showed that the development starts with subdermal and is followed by dermal periclinal divisions. They also stated that the integument arises as two halves, or valves, which are free above but become fused below especially in later stages. Unfortunately, however, they failed to give an unequivocal demonstration of this paired development by means of some good photographs. It was this lack of proof that led Puri to reject the evidence. However, it should be reported that earlier Shuhart (1932) and Leroy (1954) had published the paired initiation of the integument lobes (in Carya spec. and Platycarya strobilacea resp.), and had given photographs of microscopic slides showing cross-sections of the distal part of the nucellus flanked by two opposite tips of the young single integument. In the present paper we present two similar photographs, one of Pterocarya fraxinifolia, the other of Engelhardia spicata. In addition two other ‘true to nature’ photographs are given, showing two developing ovules of Pterocarya fraxinifolia, as they can be observed directly under a stereo dissecting microscope at low magnification, after the young pistil wall is carefully removed. There is no escape from the fact that the integument in these plants grows like two fusing lobes. The hypotheses are a different matter.
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
    Format: application/pdf
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  • 2
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    In:  Blumea - Biodiversity, Evolution and Biogeography of Plants (0006-5196) vol.36 (1992) nr.2 p.501
    Publication Date: 2016-11-24
    Description: Stemona and Pentastemona differ clearly in the size and structure of their ovules and seeds. Especially the development, shape, and cell wall thickenings of the endotestal cells, and by consequence the origin of the seed ridges, show marked differences. The embryological and seed anatomical characters support the proposal to give Pentastemona a family status.
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 3
    Publication Date: 2013-07-11
    Description: Recent phylogenetic analyses based on molecular markers have resulted in a solid phylogeny of Viburnum with 12 well-defined clades. This has allowed us to focus on character evolution, endocarp and seed characters in particular. Members of Viburnum bear drupes that differ considerably between clades. Characters such as pyrene shape and grooving, number of fibrous layers, seed coat anatomy, and seed rumination are phylogenetically highly valuable. Our results largely agree with the results based on molecular data and provide several additional insights. The position of V. clemensae as sister to the rest of Viburnum is supported by several characters. The early diversification of V. clemensae might explain its highly derived features. Furthermore, our results give an indication of the possible paraphyly of the Megalotinus clade, confirm the paraphyly of Hara’s section Solenotinus, and support the split of Hara’s section Odontotinus into four well-defined clades. Endocarp and seed characters are mainly useful at the level of individual clades. Several characters, however, are useful at higher taxonomic levels. The presence of small, amorphous crystals in the endosperm, for example, is most likely to be apomorphic for Viburnum within the order Dipsacales.
    Keywords: Viburnum ; Adoxaceae ; endocarp ; seed ; evolution ; phylogeny ; 42.43, 42.58
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 4
    ISSN: 1432-2048
    Keywords: Cell elongation ; Cell wall ; Glucan ; Phaseolus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hypocotyls of dark-grown 6-day-old seedlings of Phaseolus vulgaris L. proved to be sufficiently homogeneous to permit studies relating the rate of cell elongation to the composition of the primary cell walls. Whereas the levels of cellulose and uronic acids remained practically constant during and after cell extension, all other components showed major or minor changes. Cell-wall protein, as such, decreased by more than 50%, but indications are that hydroxyproline-rich glycoprotein increased with a decreasing rate of cell elongation, concomitant with a rise in the degree of arabinosylation of wall-bound hydroxyproline. As cell elongation slowed down, non-cellulosic glucose accumulated, presumably in the form of a β-(1–4)glucan closely associated with cellulose. These findings confirm the notion that the primary cell wall is a highly dynamic structure.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 205 (1997), S. 195-204 
    ISSN: 1615-6110
    Keywords: Dirachmaceae ; Dirachma socotrana ; Geraniales ; Rhamnaceae ; Ovule ; seed ; fruit ; taxonomic relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dirachma has a bitegmic, crassinucellate and anatropous ovule with a single median provascular tegumentary bundle. The seed coat is characterized by an exotesta and an endotegmic pigment layer. Although the fruit ofDirachma superficially resembles that of theGeraniaceae s. str., the characters of ovule and seed do not support a relationship with that family. Also a relationship withBarbeyaceae, as suggested by recentrbcL studies, is not supported by seed anatomical characters. The true relationships ofDirachma are difficult to assess on the basis of ovule and seed characters alone. TheRhamnaceae may be a closer relative.
    Type of Medium: Electronic Resource
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  • 6
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    Washington : Periodicals Archive Online (PAO)
    Middle East Journal. 31:1 (1977:Winter) 63 
    ISSN: 0026-3141
    Topics: Ethnic Sciences , History , Political Science , Sociology , Economics
    Notes: AGRICULTURAL REVIEW
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  • 7
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    Chicago : Periodicals Archive Online (PAO)
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Plant systematics and evolution 193 (1994), S. 187-212 
    ISSN: 1615-6110
    Keywords: Rafflesiaceae ; Ovule ; seed structure ; seed dispersal ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genera of theRafflesiaceae show a marked diversity in the structure of their ovules and seeds. Evolutionary trends are recognizable in ovule orientation and number of integuments. A change from anatropous ovules inApodantheae andMitrastemoideae towards incomplete anatropy inRafflesieae and orthotropy inCytineae occurs, next to a change from bitegmic ovules inApodantheae towards unitegmy with rudimentary outer integuments inRafflesieae andCytineae and full unitegmy inMitrastemoideae.—The differences in ovule structure are clearly reflected in the seeds. The seeds are essentially exotegmic, have very small embryos and an oily endosperm.—Seed structure strongly confirms the existing subfamilial classification and supports additional arguments for the generic status ofApodanthes. It does not support a separate status of the genusBerlinianche. InRafflesiaceae, seed micromorphology is only of limited use at the species level. As far as known seed dispersal is endo- or exozoochorous in all genera.
    Type of Medium: Electronic Resource
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