94 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the meristem of the growing-point small pale chloroplasts ; the chloro- 

 phyll-chains in the young cortical cells being formed from them by suc- 

 cessive bipartitions ; a minute portion of the colourless protoplasm 

 remains over in the form of the connecting strings. From the mode 

 of formation and position of the starch-grains, the author believes that 

 the nucleus plays an important part in their production. 



Prothallium of Lycopodium.* — Dr. M. Treub describes the pro- 

 thallium of a new species of Lycopodium, L. Sala'kense, found by him in 

 one spot only in Java, and allied to L. cernuum. Of the three types of 

 Lycopodium-TpTothaWinm, it belongs to that of L. cernuum, being inter- 

 mediate between that species and L. inundatum. 



Some days after the spores were sown in the laboratory they de- 

 veloped a number of small tubers or primary tubercles, and growth then 

 ceased for a time. After a lengthened period of rest, apparently inde- 

 pendent of external circumstances, a further development of the pro- 

 thallium took place into at first a single, and afterwards several filaments 

 consisting of several rows of cells lying side by side. The prothallium 

 of L. Sala'kense does not bear the small outgrowths found on that of 

 L. inundatum which perform the function of leaves, but in their place 

 small elevations. On the cylindrical portion near the apex are produced 

 first the antherids and later the archegones ; but the development of 

 these organs presents no special features. Ehizoids are almost or 

 entirely wanting; but the prothallium is green, and not saprophytic. 



The prothallia of L. carinatum, L. nummular if olium, and L. Hippuris 

 belong to the type of L. Phlegmaria, and the last contains also the 

 same endophyte. The prothallium of L. nummularifolium consists of 

 filaments which are not more than three cells in thickness. 



Influence of Light on the Origin of Organs in the Fern-embryo.t 



. Herr B. Heinricher confirms Leitgeb's statement that the origin of 



organs in the embryo of the Polypodiacese is influenced only by 

 its position in the prothallium, and is quite independent of gravity ; 

 and his observations lead also to the additional conclusion that 

 it is quite independent of light. The experiments were made on the 

 prothallium of Geratopteris thalictroides, but the author has no doubt 

 the results apply equally to the whole of the Polypodiacese. The first 

 root originates in all cases from the octant in the embryo which faces 

 the neck of the archegone. This first root exhibits extraordinarily 

 vigorous negative heliotropism ; when the light falls on the embryo 

 from below, the root rises vertically erect from the nutrient fluid, 

 unaffected by gravity. Temperature has also a very powerful influence 

 on the development of the embryo. The position of the archegones on 

 the underside of the prothallium, which is determined by light, insures 

 that the root shall be formed on the shaded, the first shoot on the 

 illuminated side. 



Muscineae. 



Acutifolium-Section of Sphagnum. J — Herr C. Warnstorf gives a 

 critical review of this group of European bog-mosses, which he further 



♦ Ann. Jard. Bot. Buitenzorg, -vii. (1888) pp. 141-50. See Bot. Contralbl., xxxvi. 

 (1888) p. 101. Cf. this Journal, 1888, p. 262. 



t MT. Bot. Inst. Graz, i. (1888) pp. 237-53 (3 figs.). 



X Verhandl. Bot. Ver. Prov. Brandenburg, 1888, pp. 79-127 (2 pis.). See Bot. 

 Ceutralbl., xxxvi. (1888) p. 69. 



