574 Pteridophyten. — Floristik, Geographie, Systematik etc. 



Lang, W. H., Studies in the Morphology and Anatom y 

 of the Ophioglossaceae. IL On the Embryo oif Hehninthostachys. 

 (Ann. Bot. XXVIII. p. 19-37. with Plate and 9 Textfig. 1914.) 



An at early stage the embryo of Hehninthostachys consists of 

 three tiers of cells, the first and second forming the suspensor the 

 third the embryo proper. The large foot arises from the hypobasal 

 part of the latter, while the apex of the stem, the first leaf and pro- 

 bably the primary root arise from its epibasal part. Campbell states 

 that the first leaf remains rudimentary, but the author finds that 

 this may or may not be so. There appears to be some doubt as to 

 whether this first leaf originates independently of the stem or from 

 the first Segment of the latter. As the embryo developes the direc- 

 tion of its growth changes. Bower has claimed that while in the 

 Seed Plants the primary root faces the suspensor and is a continua- 

 tion of the primary axis, in the Pteridophyta it is always a lateral 

 appendage. This was not so in Hehninthostachys where the root 

 appeared to originate as a continuation of the axis, though it was 

 earlj'- displaced owing to the growth of the foot. Moreover from 

 Campbell's figures of Danaea and Lyon's figure of Botrychium 

 ohUqiiuyn the primary root here too appears to be a continuation 

 of the axis; so that there is some evidence for regarding the primary 

 root of the Filicales as potentially a main or tap root, comparable 

 in Position to that of the Seed-Plants. 



The paper contains a critical account of the embryology of the 

 Filicineae. Bower's generalization that the relation of the apex of 

 the axis to the primary segmentation of the embryo is constant and 

 that this apex occupies as nearly as possible the centre of the epi- 

 basal hemisphere is accepted. His view that the possession of a 

 suspensor is a primitive character is also accepted. But whereas 

 Bower seems to regard the suspensor as biologically useful in car- 

 rying the embryo into the bulky prothallus and believes its sup- 

 pression.. associated with the development of less bulky prothalli, 

 to be a simplification advantageous in avoiding an awkward curva- 

 ture of the developing embryo the author is mclined to believe 

 that the occurrence of a suspensor and its suppression may be 

 explained on morphological rather than on biological grounds. 

 When present it would seem to represent the last indication of a 

 row of cells often formed in the lower plants on germination. It 

 may, in fact, be a juvenile filamentous stage rapidly passed over 

 or often suppressed. If this were so we should see analogies with 

 the germination of the spores of some Algae, Bryophyta and Pte- 

 ridophyta where a filamentous stage is hurried over or suppressed 

 and with the presence of a cell at the base of the sporogonium, 

 taking no part in the development of the latter. Finally it is sug- 

 gested that the presence of a suspensor in the higher Seed-Plants 

 may be a character retained from a filicinean ancestry. 



Isabel Browne (Universit}?^ College, London). 



Baker, L., Note on accommodation in Poivgala vulgaris. (Journ. 

 Bot. p. 347—350. 2 figs. December 1913.) 



This species is recorded mainly as a constituent of dry heathy 

 or grassy Vegetation. Measurements are given of 20 to 30 specimens 

 of plants from a) garden, b) heath, c) grassland, d) bog. The bog 

 form grows with Sphagnmn, Jiinciis, Molinia, Nardus and Ulex 



