658 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the majority new to science, and very nearly all collected by himself 

 between 1849 and 1862. Of these species, 283 are Jubulcre, 274 

 Jungermannicrc, and 22 Marchantierc. They are arranged under 

 51 genera, of which 8 are new, viz. Myriocolea, Clisetocolea, Arach- 

 niojisis, Mytihpsis, Anomoclada, Clasmatocolea, Syzygiella, and Sym- 

 phyomilra. Of Lejemiahe describes 234 species, which he distributes 

 among 35 sections. 



Algae. 



Development of Tissue-systems in Algae.* — LTcrr N. Willo has 

 examined the structure and development of eleven genera of Floridcae, 

 which he divides into two groups : — those with a single apical cell, 

 and those with an apical mass of cells with peripheral growth. The 

 first of these groups arc again divided into four, and the second into 

 two types. 



1. Delesseria-type. (Hydrolapathum sanguincum, Delesseria alata, 

 D. sinuosa, Odonthalia dentata). Growth always takes place by a 

 single apical cell. The transverse walls which separate the primary 

 segments are at first straight, but afterwards become curved convexly 

 below. The primary segments are divided by two vertical walls 

 into a smaller middle, and two larger marginal cells. 



2. Khodophyllis-type. (Bhodophyllis bifidus.} Here there is a 

 three-edged apical cell, from which segments capable of division are 

 separated alternately on the two sides. The thallus is afterwards 

 divided by walls parallel to the surface, and consists therefore of 

 two outer layers which have endochrome only on their outer walls 

 and form the assimilating system, and of one or more inner layers 

 which constitute the conducting system. 



3. Ceramium-type. (Ptilota elegans, Bonnemaisonia asparagoides.} 

 Tho apical growth in this group has already been fully described by 

 others. 



4. Lomentaria-type. (Lomentaria kaliformis.') The apical cell is 

 conical, and divides in several directions, some parallel to the base, 

 others nearly vertical to the surface, by which segments are separated 

 laterally. These last cells again divide rapidly into an outer large 

 and an inner small cell, the former further dividing into two. 



5. Chondrus - type. (Phyllophora Brodisei, P. membranifolia, 

 P. rubens, Chondrus crispus.) Growth in length takes place by dicho- 

 tomously branched rows of cells, the outermost of which divide by 

 anticlinal and periclinal walls. No conducting hyphre nor reserve- 

 system. The cells in the interior part of the thallus are greatly 

 elongated and united by pores, and form a conducting system. 



6. Sarcophyllis-type. {Sarcophjllis edulis, Fur cellar ia fastigiata.) 

 The mode of growth is the same as in the last type. Both conducting 

 and reserve-hyphae occur. The assimilating system consists of dicho- 

 tomously branched rows of cells, each of which is connected with one 

 or each side by a pore. 



* SB. Bot. Sallsk. Stockholm, Sept. 23, 18S5. See Bot. Centralbl., xxvi. 

 (1886) p. 86. Cf. this Journal, v. (1885) pp. 684, 841 ; ante, p. 109. 



