404 Morphologie, Teratologie, Befruchtung, Cytologie. 



Altensteinii and Bowenia spectabilis the abaxial System of foliar 

 Strands is clearly developed, but it is an adaxial accessory System 

 that constitutes the reinforcing System. Occasionally, however, in 

 the former species a small amount of vascular tissue is given off 

 into the pinna from the ends of the abaxial curve. It is held that 

 as generally in the Ferns, so generally in the Cycads the abaxial 

 System of foliar Strands serves to carry forward water for a long 

 leaf. The development of an adaxial reinforcing System may be 

 due to lack of space abaxially, or possibly to basipetal sequence in 

 the development of the pinnae, though such a System is not found 

 in all Cycads the pinnae of which develop basipetally. 



Thus among the Cycads the form of the foliar bündle seems 

 to be controlled by the sj^stematic position (sie) of the species, the 

 length of the leaf and the size of its pinnae and the order of deve- 

 lopment of the latter. 



Among the Monocotyledons three Palms (Cocos campesiris, 

 Mart., Phoenix dactylifera L. and Caryota urens L.) and one Aroid 

 {Philodendron Sellonm C. Koch.) were examined. In all of these the 

 petiole and rachis contain numerous scattered bundles. Those 

 nearest to the insertion of the pinnae give off a number of Strands 

 into the latter. There is thus no special restriction of supplying 

 and reinforcing duties to different parts of the vascular System. 

 Philodendron has larger pinnae than the Palms and its central 

 bundles contribute to the traces of the pinnae, whereas in the 

 Palms the central bundles appear to the unaffected by the departure 

 of the traces of the pinnae. 



- Thus in the Monocotyledons the form of the trace is apparently 

 determined by the scattered bündle System characteristic of the 

 group. Among Dicotyledons the authors considers the foliar bund- 

 les of Achülea millefolium L., Tripterodendron filieiforme Radlk., 

 Brownea coccinea Jacq., Spiraea Aruncus L., 5. sorbifolia L., 5. 

 Lindleyana Wall., 5". lobata Murray, Astilbe rivularis Harn., A. rubra 

 Hook. f. et Thoms., A. Thunbergii Miq., Potentilla anserina L., 

 Sambucus nigra L., Staphylea pinnata L., Heracleum Sphondylium 

 L. and Daucus carota L. 



In Achülea millefolium the pinna-trace originales marginally; in 

 Tripterodendron filicifolium in a manner recalling the extra-marginal 

 origin of the pinna-trace in the Ferns. Brownea coccinea possesses 

 a closed foliar vascular System in which there is a central Strand 

 acting as a reinforcement of the bundles in the outer series. In 

 Spiraea Aruncus the foliar bündle consists of a number of Strands 

 arranged in an ellipse; the ends of this ellipse are nipped off as 

 replicas of the parent System, the latter resuming its elliptical form. 

 In the leaf of S. lobata the bundles constitute a curved series 

 widely open adaxially and usually consisting of five large and 

 some smaller bundles. The large Strand nearest to the edge of 

 the series becomes horseshoe shaped and the arched part alone 

 passes into the pinna, leaving the two ends of the horseshoe behind. 

 This method resembles the extra-marginal Fern-type, but a small 

 actually marginal Strand passes out into the trace with the larger 

 one. In the genus Astilbe, of which three species were examined, 

 the strueture of the foliar bündle and the emission of the pinna- 

 trace are of the type found in Spiraea Aruncus. It is suggested 

 that the modification of the trace in 5. lobata is partly due to the 

 basipetal development of the pinnae. This, however, is not the 

 only factor. The author gives a list of 12 Dicotyledons, 8 woody 



