480 SUMMARY OF CURRENT RESEARCHES RELATING TO 



West Indian Florideae.* — F. Borgesen continues to publish notes on 

 new or little known AVest Indian Florideae. The new species described 

 are Chantransia bispora and Chrysymmia pyriformis, and a new genus 

 C&larthrum is founded on Chylocladia Albertisii Piccone. The author 

 finds that the glands of Chrysymmia are of different form and arranged 

 differently in each species, thus forming a good specific distinction. 

 Several other species are discussed in detail. 



Secondary Attachment in Florideae. t — J. Menz has made a care- 

 ful study of the secondary attachment which is found in certain Florideae. 

 She considers that the principal points to be worked out are : 1. What 

 elements of the thallus take part in secondary attachment ? 2. Under 

 what circumstances does the substratum remain passive ? 3. Does the 

 substratum influence the manner of the attachment ? 4. Does the 

 occurrence of secondary attachment depend at all on the nature of the 

 substratum ? These questions are all satisfactorily and clearly answered, 

 as the result of the author's work. She describes her investigation of 

 Nitophyllum punctatum, Rhodymenia ligulata, and Hypnea musci/ormis, 

 and finally gives full answers to all her questions. 1. In species which 

 have a thallus of one layer only, that layer, of course, produces the 

 attachment-hyphse, and in parts where the thallus is more than one 

 layer thick, only the outermost cell-layers, which are turned towards the 

 substratum, take part in the work. Where there is a definite cortical 

 layer, the cortical cells grow out into hyphse, as in Rhodymenia, Poly- 

 siphonia, Hypnea, and Spyridia. 2. The substratum only takes an active 

 part in the attachment when two portions of the same plant, or of the 

 same species, adhere. In all other cases the substratum remains quite 

 passive, merely acting as support to the epiphyte, and not even under- 

 going any modification. The epiphyte may form " stempel "-shaped 

 rhizoids {Ceramium on Rhodymenia), or the individual hyphaj may 

 coalesce to form a disk-shaped attachment {Hypnea on Sargassum). 

 Similar growths are formed by a more or less active increase of the 

 cortical cells, as in Rhodymenia, which retain, however, their original 

 form. 3. The manner of the attachment is not varied, according to the 

 substratum. 4. On the other hand an influence of the substratum on 

 the formation of the organs of attachment may be observed, since not 

 every substratum seems adapted in the same way to produce growth at 

 the points of contact. Such an instance is found in Colpomenia sinuosa 

 bearing as epiphyte a species of Nitophyllum. In the parts where 

 Nitophyllum touches the chromatophore-bearing cells of the Colpomenia 

 cortex it grows out in the usual way to form hyplne of attachment ; but 

 where the Nitophyllum thallus comes into contact with the hairs of 

 Colpomenia, the Nitophyllum cells remain quite passive, or nearly so, and 

 merely grow intermingled with the Colpomenia hairs. A section through 

 such a connection is figured. 



Symbiosis between Algae and Sponges.! — A. Weber van Bosse 

 describes two new species of Thamnoclonium which live in symbiosis 



* Bot. Tidsskr., xxx. (1910) pp. 177-207. 



t Oesterr. Bot. Zeitschr., lx. (1910) pp. 103-12, 13G-40 (figs, in text). 



t Ann. Jard. Bot. Buitenzorg, ser. 2, supp. iii. (1910) pp. 587-94 (2 pis.). 



