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SCIENCE 



[N. S. Vol. XLVII. No. 1206 



forinly scalariform instead of pitted as in the 

 Cycads. Dr. Stopes then takes issue with the 

 opinion expressed in the well-known test-book 

 of Scott to the effect that [in Cycadeoids] 

 the histological details of both wood and hast 

 agree precisely with the corresponding structures 

 in a recent cycad. 



It is even stated that no plants agree with 

 the Cycadeoids. In the case of long-known 

 structures represented by such profuse mate- 

 rial as the groups referred to, botanists should 

 be able to agree more closely as to the facts. 



The point involved is that while these 

 groups agree in their general structures and 

 present many points of histologic contact, 

 neither is without singularities of its own. 

 Chamberlain makes essentially the same state- 

 ment as Dr. Scott. And I see no final reason 

 for disagreement. The old cryptogamic wood 

 is in the Cycads as completely lost as in the 

 later Cordaiteans, but next the pith both the 

 existing and fossil Cycads are in very essential 

 agreement; and in both the passage from 

 scalariform to pitted wood is the same. Per- 

 haps the two groups might be considered di- 

 vergent histologically were it not for the fact 

 that Stangeria like the Cycadeoids is an essen- 

 tially scalariform type and thus forms a con- 

 necting link on the one hand; while on the 

 other, Cycadeoidea micromyela has pitted 

 wood near the cambium layer. 



The differences observed are therefore not 

 so great as they at first sight appear. And 

 such differences are found moreover in exist- 

 ing dicotyls. Thus in Trochodendron, which 

 has pronounced growth rings, the spring wood 

 presents the same scalariform type as the wood 

 of the Cycadeoids; while in the related Drimys 

 with rather suppressed growth rings the main 

 body of wood is as strikingly pitted as in Cy- 

 cads or Araucaria. The explanation is obvious 

 when the seedling of Drimys is studied. 

 There is the same transition from the scalari- 

 form to the pitted wood as in the existing and 

 fossil Cycads. It may be remarked inciden- 

 tally that were the stems of Trochodendron 

 and Drimys, as well as other Magnoliacese, 

 divested of their radial storage tissue the agree- 

 ment with both the Cycads and Cycadeoids 



would be a striking one indeed. It is easy, 

 however, to look upon this storage tissue as a 

 comparatively modern structure. There is a 

 definite suggestion that medullar reduction 

 and profuse branching are in some way corre- 

 lated with the development of thick-walled 

 storage tissue by dicotyls. It is not necessary 

 to enter further upon this topic at this time; 

 but it is evident that the facts fully sustain 

 Scott's simple form of statement as to the 

 agreement histologically of the Cycad and 

 Cycadeoid woods as based partly on the study 

 of Solms and myself. 



G. K. WlELAND 



Tale Universitt 



the relation between age and area in 

 the distribution of plants 



In a discussion of the " Age and Area " hy- 

 pothesis of Professor Willis, by E. W. Sin- 

 nott, in Science for November 9, 1917, the 

 author very justly sets out with the conten- 

 tion that " other factors than age share in 

 the area occupied by a species." Factors in- 

 herent in the plant itself, he tells us, such as 

 hardiness, adaptability, growth habit and the 

 like, play a very important part in determin- 

 ing distribution. 



As a notable illustration in support of this 

 statement, I would call attention to the rapid 

 dispersion of a comparatively recent immi- 

 grant, the Japan honeysuckle (Lonicera 

 Japonica) which now occupies a wider area 

 in our southeastern states than the longleaf 

 pine, and others of our " oldest inhabitants." 

 My first recollection of this plant goes back 

 to that now almost prehistoric time, vaguely 

 recorded in the popular mind as " before the 

 (civil) war," when it was known only as a 

 garden plant. It continued in favor as an 

 ornamental vine for piazzas and pergolas for 

 a decade or so later, until it began to " run 

 wild " at such a rate that it fell into disre- 

 pute for ornamental purposes, and is now the 

 most aggressive and indomitable enemy with 

 which our native plant population has to con- 

 tend. Unlike the common herbaceous weeds of 

 cultivation, it does not confine itself to road- 

 sides and waste places, but invades the most 

 secluded haunts of the wild flowers, strangling 



