Mabch 20, 1903.J 



SCIENCE. 



465 



maximum temperatures for eytohydrolytic 

 action; (/) relative activity in the presence 

 of varying amounts of sodium hydrate 

 and of each of the following acids : hydro- 

 chloric, acetic, oxalic, formic, citric, malic, 

 tartaric; (g) relative activity in the pres- 

 ence of the juices of the host plants of 

 this bacillus (carrot, tomato, etc.) ; (7i) 

 relative activity in the presence of the 

 products of growth of the organism. Prac- 

 tically no diastatic action occurred. 

 The full paper will soon be published. 



A New Key to the Phylogeny of the Mono- 

 cotyledons: Professor E. C. Jeffrey, 

 Harvard University. 

 Recent extensive investigations of the 

 anatomy of the higher plants, living and 

 fossil, have established beyond question 

 that anatomical features, especially in the 

 case of the larger groups, are even more 

 constant than those presented by the re- 

 productive and floral organs. This being 

 the ease, it is not surprising that they 

 should be used to an increasing extent in 

 the elucidation of phylogeny. The inten- 

 tion of the present abstract is to call at- 

 tention to the fact that there are certain 

 anatomical features of the Monocotyledons 

 which appear to be of considerable phylo- 

 genetic value. 



It has long been known that the bundles 

 of the aerial stem of the various mono- 

 cotyledonous orders are of the closed col- 

 lateral type, while those of rhizomes often 

 present a curious concentric condition, in 

 which the phloem, exactly reversing the 

 arrangement found in the vascular crypto- 

 gams, is surrounded completely by xylem. 

 The latter type of bundle has been called 

 by Strasburger amphivasal, to distinguish 

 it from the amphicribral concentric bundle, 

 which is characteristic of the vascular 

 cryptogams. 



The author has found that the amphi- 

 vasal type of concentric bundle is present 



not only in monocotyledonous rhizomes, 

 but in the nodal regions of the repro- 

 ductive axis as well. The amphivasal con- 

 centric bundles of the reproductive axis 

 make their appearance at a varying dis- 

 tance below the' nodes, and usually disap- 

 pear entirely from the stem after the leaf- 

 traces have passed off. The reproductive 

 axis is consequently divided into a number 

 of distinct phytomeres, which are charac- 

 terized at their upper ends by the presence 

 of the amphivasal concentric bundles just 

 described. Sometimes in the extreme up- 

 per part of the floral axis, where the inter- 

 nodes become shortened, the amphivasal 

 nodal segments of the axis are fused, so 

 that the flbr.ovascular tissue becomes con- 

 tinuously concentric, just as is ordinarily 

 the case in monocotyledonous rhizomes. 



The occurrence of concentric bundles at 

 the nodes of the reproductive axis has been 

 made out by the author, in the GramincEe 

 (Zizania, Phleum, Coix, Zea, Calamogros- 

 tis, Elymiis, etc.), Cyperaces {Scirpus, 

 Eriophoron, Cladium, Carex, etc.), Junea- 

 ceae and certain of the lower Liliaceas. He 

 believes that these facts furnish a vahiable 

 additional clue to the phylogeny of the 

 Monocotyledons. 



It is a well-established general principle, 

 resulting from the study of the compara- 

 tive anatomy of living and fossil gymno- 

 sperms, equi«!etales, etc., that ancestral 

 anatomical conditions are extremely apt 

 to persist in the reproductive axis. The 

 occurrence of concentric bundles at the 

 nodes of the reproductive stem in the above 

 groups is consequently, in all probability, 

 to be regarded as an ancestral feature. 

 This view gains force from the fact that 

 in Potmnogeton, etc., and many grasses, 

 the concentric bundles occur throughout 

 the stem, but only at the nodes. Moreover, 

 in the higher Liliacese, the Iridacese, the 

 Orchidaceffi, the aroids, the palms and the 

 Scitaraineas, etc., concentric bundles have 



