igoS] CURRENT LITER.iTVRE 67 



deficiencies of soils by determining how much soil is required to give normal Azoto- 

 bacter formation. — F. L. Stevt^JS. 



Fossil Osmundaceae.— KiDSlON and GwYXXE-VACGH.iN" describe the struc- 

 ture of two osmundaceous stems from the Jurassic of New Zealand. On account 

 of the difficulty of distinguishing anatomically between Osmunda and Todea, 

 they put these stems under the provisional genus Osmundites. One of the stems, 

 O. Dunlopi, is characterized by an extremely small central cylinder, comparable 

 with that found in the filmy Todeas of the present day. In this species the foUar 

 gaps are much reduced and are said by the authors even to be absent sometimes. 

 The other new species, O. gibbiana, has a better developed stele and its foliar gaps 

 are very similar to those of living species of Osmunda. The authors add something 

 to our knowledge of the Osmundites skidegatensis of Penh.^llow, from the Lower 

 Cretaceous of Western Canada. In this species they describe well-developed 

 internal phloem. The medullary tissues clearly become continuous with those of 

 the cortex through the very broad foliar gaps. Concerning this species the authors 

 sav: "At first sight (it) appears to provide something very like the dictyostelic 

 ancestor postulated by Jeffrey's theor5^" They conclude, however, with Boodle 

 and the majority of other British anatomists, since there is an absence of internal 

 phloem in the young plant of living species of Osmunda, that on the hypothesis 

 of recapitulation internal phloem and the accompanying structures must have 

 been absent m the ancestors of the Osmundaceae. This argument, Iio^'e^", 

 is quite fallacious. It would apparently be just as reasonable to assume that the 

 mesarch foliar and peduncular bundles of the Cycadales are not an ancestni! 

 feature, as is generally admitted. especiaUy in Great Britain, because forsooth 

 they have not been shown to occur in the stem of cycadean seedlings. Mor«)ver, 

 those who hold with Gw-y-nne-Vaughan, Worsdell, and others, that the cond.twn 

 without internal phloem is ancestral in the case of the tubular central Ota^" « 

 the stem in the Filicales, find likewise no ontogenetic support whatever for their 



amon 



adult is siphonostelic with internal phloem. Ontogeny at PJ^"^*^ 

 whatever on the subject of the presence or absence of interna! phloem 



tive tubular central cylinder of the fern series. Argument accordn 



. !„.,., .^^ fK -it K*»ma the case there 



good reason 



mesarch 



as ancestral for leaf and shoot in the cycadean series. The authors foltowb 

 in .garding the Botry-opterideae Z'^on.^lTJZT ^n<i^ 



group 



There is apparency no better reason for regardm 



ustral 



dUes Dunlopi and O. gibbiana as primitive Osmundaceae thari the ^^T^J 

 types, Agatks and Araucaria, as primitive aiaucanan comfeis.-E. C Je«rbt 



-ITi^OK. R,, and Gw™-V...CHAK. D. T.. On .he fossfl Osmundaceae. 

 Trans. Rov. Soc. Edinburg': 45:759-78°- ^- '-°- '9°7- 



