39] Phylogenetische Physiologie. 1079 



Verf. an gut konserviertem Material einige neue Feststellungen gemacht, die 

 wir in seiner Zusammenfassung wiedergeben: 



1. The paper deals with field material of adult stems of Dioon spimilosum, 

 D. edule, Ceratozamia mexicana, and Zamia floridana, particular attention 

 being given to Dioon spimdosum. 



2. In Dioon spinulosum the xjlem zone in a plant 6 meters in height 

 reaches a width of 10 cm, far exceeding the extent of ,anj xylem zone 

 previously described for any cycad. 



3. Dioon spinulosum, and D. edule have growth rings, which in D. sjmm- 

 losum correspond to the periods of activity which result in the for- 

 mation of crowns or cones, but which in D. edule do not correspond 

 to such periods. No growth rings wäre found in Ceratozamia mexicana 

 or Zamia floridana. 



4. Cone domes in the pith wäre studied in the four species. 



5. The histological character of the adult stem was studied in Dioon 

 spinulosum. The protoxylem consists of scalariform tracheids, from 

 which there is a gradual transition of the tracheids with multiseriate 

 bordered pits constituting the principal part of the wood. There are 

 also cells with the same origin as the pitted tracheids, but with trans- 

 verse walls which may remain thin-walled and contain starch or may 

 become lignified. Besides the leaf trace bundles, scalariform tracheids 

 are found in the large medullary rays. 



6. Both in the general appearance of transverse section and in histological 

 characters the adult trunc of Dioon spinulosum resembles that of 

 Cycadeoidea- 



146. Sinnot, E. W. Some features of the anatomy of the foliar 

 bündle. (Bot. Gaz., LI, 1911, p. 258-272, Taf. XVII.) 



Der Verf. zieht aus einer eingehenden Besprechung der betreffenden 

 Literatur und einigen neuen Beobachtungen an lebenden Cykadeen folgende 

 Schlüsse : 



„The primitive foliar bündle was a Single monarch and mesarch vascular 

 Strand. This has persisted in the leaf trace of all the Lycopsida and in the 

 blade of many of them, thus furnishing further evidence of the unity of the 

 group and of its relatively primitive position, 



This type of bündle is präsent at the base of the leaf trace in the 

 Osmundaceae and in certain of the OpJiioglossaceae, which thus seem to have 

 been early separated from the other ferns. 



The leaf bündle of the primitive palaeozoic Filicales was a diarch and 

 mesarch one. By the disapearance of its centripetal wood, this has given 

 rise to the endarch foliar Strands of living ferns, which have apparently been 

 derived from the more ancient of the Botryopterideae- 



The diarch and mesarch leaf bündle is also the primitive one for the 

 seed plants, which were developed along two main lines from forms related 

 to the early Botryopterideae, but wich had acquired the seed habit, The 

 members of the first series, including Calamopitys, Lyginodendron, and Heter- 

 angium, show the fern tendency for the protoxylem of the stele and leaf 

 trace to become continuous and in seriation with the centrifugal wood, and 

 for an ultimately endarch condition to result. The other series which includes 

 all remaining gymnosperms, and probably the angiosperms, shows in its 



