19 1 2] CURRENT LITERATURE 



349 



able phyletic sequence of families, therefore is as follows: " Gleicheniaceae, 

 Cyatheaceae (with minor groups, e.g., Woodsieae, etc.), Aspidieae." 



Miss Hume 



Marsili 



folia. The xylem has long received intensive study on account of its service 

 in conclusions concerning phytogeny; but there are symptoms that the phloem 

 is now beginning to come into its own. The stock contrasts between the sieve 



Miss 



lining 



gent granules. 



Not only does 



callus appear, as Russow showed, but the author shows that the pores are not 

 closed. "The outstanding differences are in shape and contents; the sieve 



tr cryptogams are larger and thicker walled and contain refrin- 

 nr " * * ' alls are thought to be associated 



with the fact that the sieve tubes of pteridophytes (on account of the absence 

 of secondary thickening) have to function for a long time, in some cases for as 

 much as 20 years, while in some dicotyledons and gymnosperms they are 

 renewed each year. The time is at hand when the sieve tubes can be linked 

 up in phyletic sequences as the xylem elements have been. 



Thomas 26 has discovered in the Jurassic of Yorkshire sporangia of Coniop- 

 teris hymenophylloides Brongn. and Todites Williamsoni Brongn., which support 

 the view that the former species is closely related to the modern Cyatheaceae, 

 and which furnish for the latter species additional points of resemblance to the 



modern Todea. 



Ifol 



which justifies its removal from the form-genus and its provisional placing in a 

 new genus Eboracia, related in sori and spores to Conioptcris, but very distinct 

 in the form of the fertile fronds.— J. M. C. 



American cecidology.— All students of the biological sciences will 

 be interested in the increased attention which cecidology is receiving in America, 

 and also in the fact that it is being studied by both entomologists and botanists. 

 Felt presents four papers. In the first 27 he gives a very complete list of 

 plants on which the cecidia of our American gall midges are known to occur 

 and the names of the gall-makers. Our knowledge of this group of gall-makers 

 is very indefinite, and therefore the very brief one-line descriptions may appear 

 unsatisfactory 



-„ to many who are unfamiliar with the subject. However, the 

 list^ will prove of very great value to the student of plant pathology and 

 cecidology. In a second paper 28 Felt describes 17 new species of gall midges, 



_ 2S Hume, E. M. Margaret, The history ol the sieve tubes of PUridium aqnilinum. 

 with some notes on Marsilia quadrifolia and Lygodium dichotomum. Ann. Botany 

 26: 573-587. ph. 54y 55 . i 9 i 2 . 



26 Thomas, H. Hamshaw, On the spores of some Jurassic ferns. Proc. Cambridge 

 Phil. Soc. 16:384-388. pl. 3 . 1911. 



37 Felt, E. P., Hosts and galls of American midges. Jour. Econ. Entomology 

 4-451-475- 1911. 



2* 



•, New species of gall midges. 7^.4:476-484. 1911 



