Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 65. (Budapest 1973)

Kováts, D.: Anatomical investigations on the vegetative system of Lithospermum purpureo-coeruleum L.

unstable development; however, METCALFE & CHALK referred in this regard, as obvious from the examles given, principally to tropical species of tree height. In the course of my investigations heretofore I found no medullary rays in the shoots of Lithospermum purpureo-coeruleum L. According to literature data, the medullary rays are absent from some herbaceous genera of the family Boraginaceae ; e. g. SCHIEBLER found none in the genus Borago itself (METCALFE & CHALK 1965). SOLEREDER (1899:627) stated, as generally holding for the entire family, that the elements of the xylem parenchyma have bordered-pittedly or simply pittedly thickened walls, and some pages later (p. 634) dedefinitely states, among others also for the genus Lithospermum, that the cell waUs of the xylem prosenchymatous elements are bordered-pittedly thickened. This statement probably refers to the fibre-tracheids. I have hitherto found no typical xylem fibres in the shoots of Lithospermum purpureo-coeruleum L. If they do in fact exist, they occur presumably very rarely, and the fibre-tracheids do in fact have bordered-pittedly thickened cell walls (Plate III, Fig. 2; Plate IV, Fig 1). METCALFE & CHALK'S (1965:953) statement that the cell walls of fibres are spirally thickened in the genus Lithospermum stems probably from a misunderstanding, when referring to SOLEREDER'S work published in English in Oxford, 1908 (Systematic anatomy of the dicotyledons ; English edition, translated by L. A. BOODLE and F. E. FRITSCH, Oxford, 2 vols. pp. 1183, cit. METCALFE & CHALK). I found hitherto no crystals in the xylem. METCALFE & CHALK'S (1965) assertion that cluster and other crystals are widely present in the xylem also probably refer to the xylem of the arboriform tropical species. Rhizomes multiannual, their xylem with annual rings (Plate II, Fig. 4; Plate III, Fig. 1). Incomplete annual rings frequently occuring one or two rings not closed in every year, or in some cases one side of rhizome cross-section without annual rings, but other side with 5-6 rings (Plate II, Fig. 4). Vessels with large lumina belong mostly to the early tract, vessels of the later tracts having smaller lumina (Plate II, Fig. 4; Plate III, Fig. 1). Annual rings usually 100-300 p wide; innermost (first year) ring usually widest of all, in general 600-700 p wide (Plate II, Fig. 4). Stele structure of rhizomes agreeing in other respects with epigeous shoots (sine the former are also shoots, but subterranean ones). Xylem elementx in regularly arranged parts of rhizome largely ordered into radial rows (Plate II, Fig. 4 ; Plate III, Fig. 1), in all other levels, at bifurcations or rootbrachings, of greatly disturbed structure. At a cross-section level, both cross- and longitudinal sections of xylem elements discernible concomitantly (Plate IV, Fig. 2). Phloem Primary phloem elements of a fascicular structure (similarly to xylem elements) in all young shoots, thus also in hypocotyl and epicotyl of seedling plants (KOVÁTS 1971). By an early formation of cambium also secondary elements appearing soon, thus in older shoots an increase of pholem elements and the appearance of secondary phloem elements effecting an increase also in the number of fascicles, joining by their adjacent sides and thus forming a contiguous phloem ring (Plate I, Figs. 3-4; Plate II, Figs. 1 -3). — According to JODIN (1903), already the primary phloem elements seemingly form a contiguous phloem ring in the genus Lithospermum.