56 SUMMARY OF CURRENT RESEARCHES RELATING TO 



balance of evidence is in favour of a heterosporous condition for 

 Platyzoma. Should a homosporous condition be demonstrated at a later 

 date, the anomalous condition of this remarkable fern will be further 

 accentuated. A. G. 



Anatomy and Affinity of Stromatopteris moniliformis Mett. — 

 John McLean Thompson {Trans. Roy. Soc. Edinburgh, 1918, 52, 

 133-56, 4 pis. and figs.). An account of the anatomy and affinity of 

 Stromatopteris, proposed in 1861 by Mettenius as a genus distinct from 

 Gleichenia, but united with Gleichenia by most authors. The present 

 paper is based on a careful re-examination of herbarium material, and 

 gives details regarding the external form, the dermal appendages, the 

 anatomy of stem and leaf, soral constructions, sporangial form, and 

 spore-output of Stromatopteris, thus rendering possible a clearer view 

 of its near affinities. And it is found that structurally Stromatopteris 

 can be ranged with Gleichenia, but that it has an individuality of form 

 unlike any Gleichenia. Possibly its peculiarities are due to the erect 

 position assumed by the branched portions of the axis, and are accen- 

 tuated by the poverty in roots, or the extremely xerophytic life-con- 

 ditions. The transitional types of dermal appendages, however, supply 

 a peculiarly distinctive character, and while they may be expressive 

 of special adaptation in a physiological xerophyte, they tend, at the 

 same time, to indicate that Stromatopteris is distinct from Gleichenia. 

 Stromatopteris has no close kinship with Platyzoma, and indeed has little 

 in common with it save a xerophytic life ; for in Platyzoma there 

 is a sporangial advance together with a relatively primitive vegetative 

 condition, while Stromatopteris maintains the structural and sporangial 

 character typical of Gleichenia. The author holds that Stromatopteris 

 deserves recognition as a distinct monotypic genus, closely allied to 

 Gleichenia, but clearly distinguished from it by well-marked peculiarities 

 of form and construction. A. G. 



Regeneration in Phegopteris polypodioides. — Elizabeth "Wuist 

 Brown {Bull. Torrey Bot. Club, 45, 1918, 391-97, figs.). An account 

 of experiments made upon the plant. Regeneration took place near the 

 base of the petiole of a detached leaf of a young sporophyte, placed 

 upon sand moistened with Knop's solution in moist air. A cellular 

 mass, resembling a prothallium, was formed, from which rhizoids, inter- 

 mediate structures between leaves and prothallia, and true leaves 

 developed. At first true leaves resembling those of normal young 

 sporophytes were formed ; then leaves of a much simpler type developed. 



A. G. 



New Cases of Apogamy in Ferns. — W. N. Steil {Science, 1915, 

 41, 293-4). Cultures of Aspidium tsus-simense, Pellsea adiantoides and 

 Lasirea chrysoloba were kept under observation. The developing embryo 

 of the first species produces no foot ; and the primary leaf usually 

 precedes the primary root, the stem appearing later. Numerous scales 

 are developed upon the petiole of the primary leaf, even in the very 

 young embryo, and resemble the characteristic scabs of the mature 

 plant. In Pellsea adiantoides the prothallia produce embryos apoga- 



