598 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Stomata of Lycopodium aunotinum.* — J. Borodine publishes a note 

 on the remarkable distribution of the stomata on the leaves of Lycopo- 

 dium annotinum. Each annual shoot exhibits a regularized variability 

 in the relation between the number of stomata on the upper and under 

 surfaces of the leaves. The 1-4 basal leaves have stomata on the upper 

 surface only ; in the successive leaves stomata are found on the under 

 surface, and their number on the under surface becomes larger and larger. 

 They first appear near the basal margin and gradually cover the whole 

 surface except the costa. On the upper leaves they rapidly diminish to 

 zero. Also most of the leaves formed in summer possess stomata on the 

 under surface only. But towards the end of the season the last formed 

 nearly erect leaves produce more and more stomata above and fewer and 

 fewer beneath. Borodine shows also that this tendency to produce a 

 considerable number of leaves destitute of stomata on their upper surface 

 undergoes certain variations. 



Sagenopteris and Hydropterangium.f — T. G. Halle writes on the 

 Swedish species of Sagenopteris Presl and on Hydropterangium, a new 

 genus. He thinks it probable that the Marsilia-like fossil leaves called 

 Sagenopteris belong to the Hydropterideae, though their stomata occur 

 on the upper surface only. This position of the stomata prevented 

 Schirnper from placing Sagenopteris in Hydropterideas. Halle also de- 

 scribes under Hydropterangium marsilioides some sporocarp-like bodies 

 which are frequently found with Sagenopteris, and suggests that they 

 may be closely related to one another. No spores were found, but the 

 structure of Hydropterangium recalls Marsilia. Halle figures a series of 

 leaves of S. undulata and S. Nilssoniana, in order to show the great 

 variation that they present under each species. 



K. Yasui % describes the life-history of Salvinia nutans, treating first 

 of the microspore-formation and of the male prothallium, and then of 

 the megaspore-formation, the female prothallium, fertilization, and em- 

 bryo. The text is in Japanese. Some 93 highly magnified figures of 

 the development of the various parts are given on the two folding plates. 



Cones of Selaginella.§ — M. G. Sykes and W. Stiles describe four 

 main types of sporophyll in SeJaginella. 1. In S.pumila, S. rupestris, and 

 other species, the sporophyll has a well developed dorsal flap extending 

 freely downwards and protecting the young sporangium immediately 

 below it. Two of the species have radially arranged leaves and are 

 presumably among the more primitive members of the genus. '2. In 

 S. spinosa, the only other radial species examined, there is nothing which 

 can certainly be compared with this free dorsal flap. A slight dorsal 

 swelling is present, occupied by an air-cavity ; it is possible that this 

 may represent the reduced remains of such a flap. In this species the 

 sporophyll is flat and the sporangium exposed. 3. In S. helvetica, one 

 of the dorsiventral species, there is a well-developed dorsal projection, 

 which is, however, not free but decurrent. It is especially prominent 



* Ann. Jard. Bot. Buitenzorg, 3« Suppl. (1910) pp. 447-52. 

 t K. Svensk. Vet. Akad. HandL, xlv. No. 7 (1910) 16 pp. (3 pis.). See also 

 Bot. Zeifc., lxviii. (1910) pp. 165-6. 



J Tokyo Bot. Mag., xxiv. (1910) pp. 81-91, 123-37. 

 § Ann. Bot., xxiv. (1910) pp. 523-36 (pi.). 



