35] Phylogenetische Anatomie. 829 



126. Compton, R. H. Theories of tlie anatomical tiansitiou 

 froiu root to stein. (New Phytologist XI, 1912, p. 13 — 25, mit 1 Textfig.) 



Es wird ein historischer und kritischer Bericht gegeben über die ver- 

 schiedenen Theorien, die mit der Keimlingsanatomie in Verbindung stehen. 

 Die Ansichten von van Thieghem, Gerard, Bonnier, Sterckx, Miss Thomas, 

 Chauveaud und anderer werden diskutiert und die verschiedenen Methoden 

 zur Veranschaulichung der Prozesse, die mit dem ,, Übergang" in Verbindung 

 stehen, werden mittelst vergleichender Diagramme demonstriert. 



127. Compton, R. H. An Investigation of the Seedling Struc- 

 ture in the Leguminosae. (Journ. Linn. Soc. Bot. XLI, 1912, p. 1 — 122, 

 9 Taf.) 



Die umfangreiche Arbeit nimmt zu der vielfach erörterten Frage, inwie- 

 weit die innere und äussere Struktur der Keimlinge für phyllogenetische 

 Schlüsse von Wichtigkeit sind, in kritischer Weise Stellung. In dem speziellen 

 Teil werden zahlreiche Vertreter der meisten Tribus behandelt, so dass man 

 ein Bild der Keimlingsentwicklung der ganzen Familie bekommt. Die Haupt- 

 ergebnisse werden folgendermassen zusammengefasst : 



,,1. The stable tetrarch type of symmetry is found typically in seed- 

 lings of large size. 2. The production of large seeds and seedlings is correlated 

 W'th the treehabit. 3. The arboreal habit is in all probability primitive in the 

 Legniminosae as in Angiosperms generally, the herbaceous habit derived. 

 4. The stable type of tetrarchy is therefore probably fundamental and primitive 

 for the whole family. 5. Reduction in the size of the seedling has given rise 

 to an unstable type of tetrarchy, in which the intercotyledonary xylems, 

 though cotyledonary in nature stand in an intim ate Supplement ary relation 

 to the early plumular traces. 6. Triarchy and diarcby are closelj associated 

 with this unstable form of tetrarchy. The whole group of types of symmetry 

 is in a highly variable condition, all three forms co-existing within Single 

 tribes, genera, species, and even individuals. 7. Diarchy is the final term in 

 this reduction-series; and wlien attained it is offen extremely stable. 8. The 

 whole series given above applies mainly to epigeal types. In cases of hypogeal 

 germination, in which the plumule develops fast, the epicotyledonary traces 

 may be directly represented by primary xylem in the root. 9. In particidar 

 the hypogeal Vicieae exhibit a very constant triarch structure, in which two 

 xylems are cotyledonary the third plumular. This type has no connection 

 with the epigeae form of triarchy. 10. Other types of structure found in the 

 family are derivable from the stable form of tetrachy. 11. The anatomical 

 transitions from root-to stem -structure are classified into three main and 

 two subsidiary grades according to the level at which they take place. Low 

 transitions are characteristic of massive, high transitions of slender, hypo- 

 cotyls; while intermediate transitions are found in hypocotyls of intermediate 

 diameter. 12. The diameter of the axis is the raost important factor in deter- 

 mining the level of transition; length of hypocotyl has a subordinate, and 

 largely physiological, effect. 13. Since both the type of symmetry and the 

 level of transition are so closely related to the size of the seedling, it appears 

 that these anatomical characters are not likely to be of more value in solving 

 phylogenetic problems than the size-characters themselves. 14. Within nar- 

 rowly restricted groups, however, it seems that a type of symmetry, or a cer- 

 tain arrangement of bundles or vascular elements, or even in isolated instances 

 a tendency towards a particular level of transition, may be presen^ed here- 



