226 SUMMARY OF CURRENT RESEARCHES RELATING TO 



by the entire tissue decreases, and the lenticels appear somewhat 

 depressed. This firm dry mass of tissue constitutes, therefore, a pro- 

 tection to that which lies beneath, and its physiological function is 

 the same as that of the lenticels in flowering plants. 



Stomata in the Leaf-stalk of Filicineae.* — H. Potonie states that 

 the arrangement of the stomata in the leaf-stalk of Filicinete has a 

 direct relation to the anatomical structure of the stem and to the 

 development of the mechanical tissue. The latter is always perijpheral, 

 and forms the cylinder of stereome or sclereuchyma ; but it may 

 either be hypodermal, or separated from the epidei-mis by a paren- 

 chymatous assimilating tissue. In the former case the stomata are 

 arranf^ed in two rows on the two sides of the leaf-stalk ; in the latter 

 case they are distributed over its surface. The former arrangement 

 occurs in Adiantum, Anemia, Cyathea, Cystopteris, Davallia, Dicksonia, 

 Gymnogr amine, Lomaria, Lygodium, Nephrodium, Nephrolepis, Onoclea, 

 Pellcea, Pohjpodium, and Fteris; also in HymenopJiyllum and Tricho- 

 manes, as far as relates to the structure of the stem. The second form 

 occurs in Alsophila, Asplenium, Marattiaceee, Marsilia, and Todea, 

 although in the last the parenchyma subsequently passes into stereome. 



The author gives the following classification of Filicineje in 

 reference to this point of structure : — 1. "Without stomata in the leaf- 

 stalks: Hymenophyllacese [Salviniaceaej. 2. Stomata arranged in 

 two rows: Polypodiacese, Cyatheacese, Schizseaceae [Gleicheniacete]. 

 3. Stomata distributed over the surface of the leaf-stalk : Osmundacese, 

 Marattiacefe, Ophioglossacese, Marsiliacese. 



Adventitious Buds on the Lamina of the Frond of Asplenium 

 bulbiferum.t — E, Heinricher has pursued his investigations on this 

 subject, especially as regards the youngest stages, for the purpose of 

 confirming his previous statement \ that these buds may originate 

 from a single superficial cell, in which triangularly segmented apical 

 cells were formed. The general result obtained may be stated as 

 follows : — These adventitious buds proceed from a single superficial 

 cell, which proceeds immediately to the formation of a three-sided 

 apical cell. This apical cell is usually the result of three divisions ; 

 but cases are depicted in which it results from two and from four 

 divisions respectively. The conclusion of the author is, therefore, 

 at variance with that of A. Zimmermann, that several epidermal cells 

 may take part in their formation. 



Anatomy and Classification of Schizaeace8B.§ — K. Prantl pub- 

 lishes a preliminary treatise, occupied chiefly with the classification of 

 this tribe of ferns. The following are the genera and subgenera 

 which he adopts: — (1) Lygodium {Palmata, Flexuosa, Voluhilia)', 

 (2) Mohria; (3) Aneimia [Trochopteris, Hemianeimia, Euaneimia, 

 Aneimiorrhiza) ; (4) Schizcea. 



* JB. K. Bot. Gart. Berlin, i. (1881) pp. 310-17. See Bot. Centialbl., viii. 

 (1881) p 70. 



t SB. K. Akad. Wiss. Wien, Ixxxiv. (1881) p. 115-20 (1 pi.). 

 X See this Journal, ii. (1879) p. 597. 

 § Englcr's Bot. Jahrb., ii. (1881) p. 297. 



