Foliar Venation — Pray 
13 
Fig. 21. Illustrating the general nature in paradermal 
section of the ground meristem and procambial reticu- 
lum at a median phase of leaf development, X 600. 
Secondary at extreme upper left. 
SUMMARY 
Standing of variation in foliar venation and the 
significance of such variation in systematics. 
The foliar venation of Bobea elatior has been 
described. The distinctive feature of the vena- 
tion pattern is a minor vein system composed 
of elongate, similarly oriented areoles, usually 
lacking vein endings. Thus the minor veins 
produce in some areas of the lamina a line- 
olate effect. An ontogenetic investigation of 
the lamina showed that the elongate areoles 
making up the minor venation are derived by 
a fairly precise differentiation process from a 
plate-meristem of markedly elongate cells, 
whose arrangement clearly foreshadows the 
vein pattern of the mature leaf A comparison 
is made between the development of the vena- 
tion of Bohea and that of other known types. 
REFERENCES 
Esau, Katherine. 1953. Blant Anatomy. 
xiid-735 pp., 85 pis. John Wiley and Sons, 
New York. 
Ettinghausen, C. 1861. Die Blatt-Skelete der 
Dicotyledonen mit hesonderer Kuckskht anf die 
Untersuchung und Bestimmung der fossilen 
Pflanzenreste. xlvi+308 pp., 276 figs., 95 
pls.-.Wien. 
Foster, A. S. 1945. The foliar sclereids of 
Trochodendron aralioides Sieb and Zucc. 
Arnold Arboretum Jour. 26: 155-162, 4 pis. 
1950. Morphology and venation of 
the leaf in Quiina acutangida Ducke. A?ner. 
Jour. Bot. 37(2): 159-171, 18 figs. 
1952. Foliar venation in angiosperms 
from an ontogenetic standpoint. Amer. 
Jour. Bot. 39(10): 752-766, 14 figs. 
Metcalfe, C. R., and L. Chalk. 1950. Anat- 
07ny of the Dicotyledons. 2 vols., lxiv+1500 
pp., 317 figs. Oxford, Clarendon Press. 
Pray, T. R. 1953. "Morphological and histo- 
genetic studies on the foliar venation of 
certain angiosperms." 270 pp., 150 figs. 
Ph.D. dissertation. University of California, 
Berkeley. 
1954. Foliar venation of angiosperms. 
I. Mature venation of Liriodendron. Amer. 
Jour. Bot. 41(8): 663-670, 12 figs. 
1955^. Foliar venation of angio- 
sperms. IE Histogenesis of the venation of 
Liriodendron. Amer. Jour. Bot. 42(1): 18-27, 
16 figs. 
1955<^. Eoliar venation of angio- 
sperms. III. Pattern and histology of the 
venation of Hosta. Amer. Jour. Bot. 42(7): 
611-618, 11 figs. 
1955c. Eoliar venation of angiosperms. 
IV. Histogenesis of the venation of Hosta. 
Amer. Jour. Bot. 42(8): 698-706, 9 figs. 
Solereder, H. 1908. Syste?natic Anatomy of 
the Dicotyledons. 2 vols., xii+1183 pp., 189 
figs. Oxford, Clarendon Press. 
