Anomalous Secondary Thickening in Stegnosperma (Phytolaccaceae)

E., Horak, Karl

doi:10.2307/2484898

Cited by 29 publications

(26 citation statements)

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“…His materials were probably stems of insufficient diameter to show successive cambia. Successive cambia were since reported in Monococcus (Jansen, Ronse Decraene & Smets, 2000) and in Stegnosperma (Horak, 1981), based on specimens of larger diameter. If one compares presence of successive cambia to diameter of stem or root, however, the correlation within Caryophyllales is too weak to support either of the two hypotheses for origin of (or loss of) this feature.…”

Section: Resultsmentioning

confidence: 96%

Caryophyllales: a key group for understanding wood anatomy character states and their evolution

Carlquist

2010

Botanical Journal of the Linnean Society

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Definitions of character states in woods are softer than generally assumed, and more complex for workers to interpret. Only by a constant effort to transcend the limitations of glossaries can a more than partial understanding of wood anatomy and its evolution be achieved. The need for such an effort is most evident in a major group with sufficient wood diversity to demonstrate numerous problems in wood anatomical features. Caryophyllales s.l., with approximately 12 000 species, are such a group. Paradoxically, Caryophyllales offer many more interpretive problems than other 'typically woody' eudicot clades of comparable size: a wider range of wood structural patterns is represented in the order. An account of character expression diversity is presented for major wood characters of Caryophyllales. These characters include successive cambia (more extensively represented in Caryophyllales than elsewhere in angiosperms); vessel element perforation plates (non-bordered and bordered, with and without constrictions); lateral wall pitting of vessels (notably pseudoscalariform patterns); vesturing and sculpturing on vessel walls; grouping of vessels; nature of tracheids and fibre-tracheids, storying in libriform fibres, types of axial parenchyma, ray anatomy and shifts in ray ontogeny; juvenilism in rays; raylessness; occurrence of idioblasts; occurrence of a new cell type (ancistrocladan cells); correlations of raylessness with scattered bundle occurrence and other anatomical discoveries newly described and/or understood through the use of scanning electron microscopy and light microscopy. This study goes beyond summarizing or reportage and attempts interpretations in terms of shifts in degrees of juvenilism, diversification in habit, ecological occupancy strategies (with special attention to succulence) and phylogenetic change. Phylogenetic change in wood anatomy is held to be best interpreted when accompanied by an understanding of wood ontogeny, species ecology, species habit and taxonomic context. Wood anatomy of Caryophyllales demonstrates problems inherent in binary character definitions, mapping of morphological characters onto DNA-based trees and attempts to analyse wood structure without taking into account ecological and habital features. The difficulties of bridging wood anatomy with physiology and ecology are briefly reviewed.

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Section: Resultsmentioning

confidence: 96%

Caryophyllales: a key group for understanding wood anatomy character states and their evolution

Carlquist

2010

Botanical Journal of the Linnean Society

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“…Phytolacca and Stegnosperma (Fig. 3.3A-D) are examples of plants forming a normal cambium from the initial ring of primary vascular bundles, but that meristem eventually is covered by vascular tissues from supernumerary cambia which are initiated on the outer face of the phloem (Wheat 1977;Horak 1981a). Contrasting this, in Nyctaginaceae formation of supernumerary cambia occurs precociously and usually without any appreciable amount of normal cambial activity (Studholme and Philipson 1966;Esau and Cheadle 1969;Stevenson and Popham 1973).…”

Section: Occurrence Of Normal and Anomalous Typesmentioning

confidence: 99%

“…Secondary growth of Stegnosperma is noteworthy because these plants produce 5-15 mm normal cambial growth before successive cambia are established (Bedell 1980;Horak 1981a). Vessels were mostly solitary, occasionally in radial pairs or short chains.…”

Section: Phytolaccaceous Alliancementioning

confidence: 99%

“…Descriptions of phloem cell types, other than features of sieve-element plastids (see Chap. 5), have been scanty, and thorough analyses of cells in secondary xylem are available only for several families, particularly in the Cactaceae (Gibson 1973(Gibson , 1975(Gibson , 1977a(Gibson ,b, 1978b) and a few genera of special phylogenetic significance (Gibson 1978a;Bedell 1980;Horak 1981a).…”

Section: Introductionmentioning

confidence: 99%

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Vascular Tissues

Gibson¹

1994

Caryophyllales

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“…Horak (1981), Rajput and Rao (2003) and Tamaio and Brandes (2010) have comparatively analyzed the cambia and their derivative tissues of species having multiple vascular cylinders (successive cambia) and found quantitative differences between them. These either decrease (Phytolaccaceae; Horak, 1981) or increase (Menispermaceae; Rajput and Rao, 2003) to the periphery, most distinctly obvious in the length of the vessel elements (Horak, 1981). In Menispermaceae however, differences exist between different taxa (Cocculus hirsutus vs. Abuta grandifolia).…”

Section: Statistical Analysesmentioning

confidence: 99%