The Double Leaf Trace

1908 ◽  
Vol 45 (4) ◽  
pp. 285-286
Keyword(s):  
Leaf Trace

scholarly journals Specialised emission pattern of leaf trace in a late Permian (253 million-years old) conifer

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Hai-Bo Wei ◽  
Zhuo Feng ◽  
Ji-Yuan Yang ◽  
Yu-Xuan Chen ◽  
Jia-Jia Shen ◽  
...  
Keyword(s):  
Leaf Trace ◽  
Late Permian ◽  
Emission Pattern

scholarly journals Domain pattern in the cambium of young Platanus stems

2015 ◽  
Vol 42 (4) ◽  
pp. 637-648 ◽  
Author(s):  
J. Krawczyszyn
Keyword(s):  
Annual Ring ◽  
Vascular Cambium ◽  
Leaf Trace ◽  
Domain Pattern ◽  
Size And Shape ◽  
Middle Leaf ◽  
The Right

In the vascular cambium of Platanus Z and S domains appear in the course of formation of the first annual ring. Their arrangement is connected with the division of the stem into nodes and internodes. In each node a domain of Z and of S type occurs. The longitudinal boundaries between them run along the middle leaf trace and on its opposite side, and the transverse boundaries lie in the nodes. Z-type domains are found on the right below the base of the nearest upper leaf, and S-type domains on the left. As the young cambium forms further rings, the size and shape of the domains changes.

scholarly journals XXVI.—The Anatomy and Affinity of Deparia Moorei, Hook.

1916 ◽  
Vol 50 (4) ◽  
pp. 837-856
Author(s):  
John M'Lean Thompson
Keyword(s):  
Vascular System ◽  
Leaf Trace ◽  
Cultural Conditions ◽  
Marked Variability

Summary and ConclusionsI have no information regarding the gametophyte, nor have I examined the structure of axis and leaf in young plants. It must therefore remain to be seen what light such data may throw upon the problem of the phyletic place of Deparia Moorei. The nature of the stele, the leaf-trace, and the venation, in very young plants, would also present points of value. But it will be at least evident that the vascular system of the axis is, in mature plants, of an advanced type, and it may reasonably be affirmed that the marked variability in the degree of dictyostely is an index of an inherent plasticity. It seems reasonable to suggest that the reductions in size, and simplification of structure in the direction of solenostely shown in fig. 40, is related to the cultural conditions. The plant from which the material was derived had lost ground both in size and healthiness of its leaves.

Xylary union between elongating lateral branches and the main stem in Populus deltoides

1983 ◽  
Vol 61 (4) ◽  
pp. 1040-1051 ◽  
Author(s):  
Philip R. Larson ◽  
David G. Fisher
Keyword(s):  
Populus Deltoides ◽  
Secondary Xylem ◽  
Cambial Activity ◽  
Main Axis ◽  
Main Stem ◽  
Leaf Trace ◽  
Primary Xylem ◽  
Lateral Bud ◽  
Lateral Branches ◽  
Secondary Vessels

The vasculature of elongating lateral branches was examined to determine how vessels produced in the branch unite with those produced in the main stem axis to form a continuous transport system. In a previous study it was found that differentiation of both primary and secondary xylem in a lateral bud or branch is independent of that in the main axis; i.e., xylem does not differentiate into the bud or branch from the main axis. When serial sections of the nodal region are followed downward, the bud vascular cylinder merges with that of the main axis and the adaxially situated bud traces (those nearest the stem) enter the bud gap margin first. The primary vessels of these bud traces differentiate in an oblique downward path along the margins of the bud gap, and they form radial files of primary vessels that lie adjacent to primary xylem of leaf traces in the stem. Traces situated more abaxially in the bud (those farther from the stem) contribute to other radial files of primary vessels, each of which lies progressively closer to the bud gap. Secondary xylem is initiated in the stem before it is in the branch. Consequently, the last-formed metaxylem vessels of the bud traces are continuous with secondary vessels of the stem. These latter vessels lie in the stem secondary xylem immediately external to primary xylem from the bud. Secondary xylem in the branch is initiated when foliage leaves and internodes mature. Secondary vessels formed in the branch traces are continuous with secondary vessels in the stem; these vessels are embedded in a matrix of fibers. Because cambial activity is more vigorous in the stem than in the branch, two vessels that are radially adjacent in the branch may be widely separated by fibers in the stem. The central trace of the axillant leaf enters the gap immediately below the last branch traces; at this level in the stem the leaf trace vasculature is entirely primary. The stem secondary xylem that overlies the leaf trace is continuous with that in the axillary branch.

scholarly journals XI.—The Pinna-Trace in the Ferns

1915 ◽  
Vol 50 (2) ◽  
pp. 349-378 ◽  
Author(s):  
R. C. Davie
Keyword(s):  
Vascular System ◽  
Leaf Trace ◽  
The Past ◽  
Different Types

The relation of the leaf-trace to the vascular system of the stem in the Ferns has been exhaustively investigated during the past fifteen years by various workers, especially by Gwynne-Vaughan and Boodle in this country and by Jeffrey and his pupils in America. The interpretations of the numerous types of Fern stele and leaf-trace have caused much discussion. And the discovery of a wonderful series of fossil Ferns has not settled the discussion of the evolution of the Filicinean vascular system, but has carried the battle on to another field.The fossils have recently yielded up the structure of their pinna-traces (Kidston, '08; Bertrand, '09; Gordon, '11). Simultaneously an attack has been made on the pinna-traces of living Ferns. Various pinna-traces were described in curious mathematical formulæ, but no comparisons were made of the different types, by Bertrand and Cornaille ('02) in their Étude sur quelques caractéristiques de la structure des Filicinées actuelles.

scholarly journals I.—On the Leaf-Trace in some Pinnate Leaves

1918 ◽  
Vol 52 (1) ◽  
pp. 1-36
Author(s):  
R. C. Davie
Keyword(s):  
The Other ◽  
Leaf Trace ◽  
Tabular Form ◽  
General Survey ◽  
The One

In a general survey of the pinna-traces of Ferns (Davie, '14), the results of which have been summarised in tabular form (loc. cit., p. 354), two main types of pinnatrace were described and contrasted. In the one—the “extramarginal”—the pinnatrace leaves the back of the hook formed by the incurved edge of the leaf-trace; in the other—the “marginal”—the outwardly directed margin of the leaf-trace is simply nipped off as the pinna-trace. The more primitive Ferns in the evolutionary scale, and the first leaves of both primitive and advanced Ferns, exhibit the marginal type of pinna-trace; the extramarginal type of pinna-trace is found in those Ferns which stand midway between the extreme types in the system of classification, and in some advanced forms.

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