74 SUMMARY OF CURRENT RESEARCHES RELATING TO 



modifications occurring in other members of the same genus are also 

 described. In Lonicera tatarica the network is complete, but in L. xylo- 

 steum and L. nigra it is interrupted here and there, especially opposite 

 the woody bundles. In Symphoricarpus the network is remarkable on 

 account of the doubling back of the bands on the external face of the 

 cells. 



In conclusion, the author states that of the nino genera of Capri- 

 foliaceao ho has examined, six arc provided with a super-cndodermal 

 network, and three are destitute of that structure. The structure in 

 Caprifoliacese agrees with that found in Conifer® and Kosaccfe, but it 

 differs from the Crucifene in that, in the latter case, the meshes are 

 reticulated. 



Arrangement of the Fibro-vascular Bundles in Pinguicula.* — 

 MM. P. A. Dangeard and Barbe describe the structure of the fibro- 

 vascular bundles found in Pinguicula vulgaris. According to MM. van 

 Tieghem and Douliot,f the conducting bundles may be arranged in three 

 different ways. They may be grouped in a circle, or in several con- 

 centric circles, round the axis forming a central cylinder surrounded by 

 endoderm and cortex ; or they may be grouped in several circles, round 

 several different axes, forming as many distinct central cylinders ; or 

 lastly, they may be isolated, and not united into a central cylinder. In 

 the stem of Pinguicula the authors state that the second of these arrange- 

 ments is found, and that this has only been observed in two other genera 

 of Phanerogams, namely, in Auricula and Gunnera. 



Distribution of Fibro-vascular Bundles in the Petiole .% — M. L. 

 Petit states that, if a transverse section be made at the caulinary end of 

 the petiole of Juglans regia, the fibro-vascular bundles will be found 

 arranged in three circles. These fuse together, and form a single 

 triangular bundle. The arrangement in the other Juglandeaa is some- 

 what similar, with the exception of the distribution of the accessory 

 bundles situated .above this bundle. In Liquidambar imberbe the fibro- 

 vascular system is arranged in three arcs of a circle, which form three 

 bundles. These subsequently fuse together, forming a single bundle. 

 In Bauhinia racemosa the lateral bundles have their xylem inter- 

 nally, their phloem externally ; in the median bundles the phloem 

 faces the median plane, and the xylem is opposite to that of the external 

 bundles. 



Vascular Bundles in the Rhizome of Monocotyledons.§ — Herr W. 

 Laux describes what he terms the " perixylematic " concentric bundles 

 in the rhizome of Acorus, the Juncaceas, and Cyperacea3, as contrasted 

 with the " periphloematic " concentric bundles of Ferns, the phloem 

 being, in the former, completely surrounded by a layer of xylem. There 

 is no other difference between these concentric bundles of the rhizome 

 and the collateral bundles of the aerial stem and leaves, except in the 

 relative position of the xylem and phloem. Transitions are exhibited 

 from one form to the other in the gradual collection of the xylem round 

 the phloem ; and perixylematic bundles are to be found in the nodes of 



* Bull. Soc. Bot. France, xxxiv. (1887) pp. 307-9. 

 t See this Journal, 1887, p. 260. 

 J Bull. Soc. Bot. France, xxxiv. (1887) pp. 301-3. 



§ Laux, W., ' Ein Beitr. z. Kenntn. d. Leitbiindel im Ehizom monocotyler 

 Pflauzen,' 49 pp. and 2 pis., Berlin, 1887. See Bot. Ztg., xlv. (1887) p. 611. 



