G8 SUMMARY OF CURRENT RESEARCHES RELATING TO 



development in Halopteris scoparia, but he lias not described the process 

 in detail. In the present paper he describes and figures all the stages 

 of growth of H. scoparia, in which species the process of development is 

 quite different from that of Cladostephus. In Halopteris the successive 

 filaments, instead of appearing independently from one another, grow 

 one on the other. This is described in detail. He finds that plantlets 

 arising from rhizoids which are given off by gemmae are themselves a 

 kind of gemma;, and resemble a fragment detached from the plant- 

 mother. On the other hand, the plantlets which result from germina- 

 tion possess an indirect development, which represents probably the 

 the different phylogenetic stages. 



The author has further made a special study of Sphacelaria radicans, 

 in which he finds that the ramification is exclusively adventive and of 

 pericystic origin. He considers that 8. radicans probably figures 

 among the ancestors of Halopteris, but is separated from them by inter- 

 mediates which have disappeared or of which we know nothing. The 

 pericystic origin of the rhizoids and of the adventive shoots, the 

 presence of certain holoblastic branches, and the germination of 

 the hairs, indicate a closer connection between 8. radicans and the 

 Holoblastea) than between it and the Sphacelariae, which are purely 

 Hemiblastete. At the same time, there is a vast difference between the 

 disposition of the sporangia of 8. radicans and those of Halopteris. 

 The author then discusses other alliances of 8. radicans. 



Colpomenia sinuosa.* — C. Sauvageau adds a further note to his 

 information concerning this alga. During a stay at the village of 

 St. Denis on the He d'Oleron he found specimens of G. sinuosa, growing 

 principally on Halopithys. Its presence there constitutes a danger to 

 the oyster-culture of the Marennes. In a footnote the author comments 

 on the various hosts on which the species has been found growing. 



Mucilage-glands of Undaria.f — K. Yendo has discovered a mucilage- 

 gland on the blade of Undaria pinnatifida var. distans, and has made a 

 minute study of its structure. The glands vary in size and shape 

 according to their stage of development and position in a pinnule. 

 Very few, if any, occur in the stem of rachis, and none were detected in 

 the rhizines or sporophylls. Such glands have never been recorded in 

 members of the Laminariacea} other than Japanese, and they are only 

 now described in detail for the first time. Okamura records minute 

 dark dots which are thickly scattered over both surfaces of the lamina 

 -of Undariopsis Peterseniana Miy. and Okam., and similar bodies have 

 been seen by Prof. Miyabe in Undaria pinnatifida, and by the author of 

 the present paper in Hirome undarioides. Whether all these bodies on 

 the other species are also mucilage-glands of the same sort the author is 

 unable to say, since they were seen on dried material. After describing 

 his investigation in detail, Yendo draws up the following summary : — 



(1) Undaria has numerous glandular cells scattered in the lamina ; 



(2) as a rule, each glandular cell originates from a single cortical cell 

 which is in contact with the epidermal layer ; (8) the epidermal cell 



* C.R. Soc. Biol. Bordeaux, lxvi. (1909) pp. 80S-7. 

 t Ann. Bofc., xxiii. (1909) pp. 613-21 (1 pi.). 



