72 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the methods of preparing samples for examination, the origin of peat, 
structure in coal, microscopic examination of coal, the microscopic 
components in detail — namely, humic matter, resinous matter, spore 
exines, rodlets (some of which are traced to the mucilage canals of the 
Medullosae), fungi — and, finally, a comparison of the structures of the 
coals. A. Gepp. 
Branching of the Zygopteridean Leaf and its Relation to the 
Probable “ Pinna ” Nature of Gyropteris sinuosa Goeppert. — B. Sahni 
(Annals of Botany , 1918, 32, 369-79, 3 figs. ; see also Bot. Gmtralbl ., 
1919, 140, 165). The author’s view of the branching of the 
Zygopteridean leaf is opposed to those put forward by P. Bertrand and 
by Kidston and Gwynne-Yaughan. In all Zygopteridem there are but 
two rows of pinnas (secondary raches), one on each side of the leaf. 
The supposed secondary raches of Stauropteris, Metaclepsydropsis, 
Diplolabis , Dineuron and Elapteris are really tertiary (pinnules), and the 
result of the forking of the true secondary raches. The latter are 
completely fused to the primary rachis, but their strands are distinct. 
It is probable that Gyropteris sinuosa is a secondary rachis of a form 
like Metaclepsydropsis or Diplolabis with an acquired cortical sheath 
independent of the primary rachis. The mode of branching of the 
Stauropteris leaf conforms to the rectangular system. The laminated 
portions of the Zygopterid leaf were probably expanded more or less 
horizontally, with all the segments in the same place. Clepsydropsis 
Unger (1856) is extended so as to include Ankyropteris P. Bertrand 
(1909), but contains two sections named after the two original genera 
respectively. The Zygopterideae are divided into two sub-families, 
Clepsydrodeae and Dineuroideae, on the basis of the vascular structure. 
And a table is given which shows the relations of the genera with a 
modification of P. Bertrand’s latest scheme. A. G. 
Polypodium vulgare as an Epiphyte.— Duncan S. Johnson (Bot. 
Gaz ., 1921, 72, 237-44, figs.). A number of examples of this species 
growing as an epiphyte high up on the north side of unbranched trunks 
of Quercus Prinus near Baltimore, in Maryland. Apart from their 
smaller size they apparently differed in no way from terrestrial examples. 
The author discusses the food of epiphytes, and the origin of temperate 
zone epiphytes — a tropical origin according to Schimper ; and claims that 
Polypodium vulgare is an endemic epiphyte of the temperate zone, a 
facultative epiphyte, a hardy plant with thick-cuticled fronds capable 
of rolling up in dry weather and so checking transpiration. A. G. 
Vegetative Reproduction and Aposporous Growths from the 
Young Sporophyte of Polypodium irioides. — W. NT. Steil (Bull. Torrey 
Bot. Club , 1921, 48, 203-5, figs.). An account of the sporophytic 
and gametophytic outgrowths obtained from young sporophytes which 
had developed from prothallia cultivated on nutrient solution under 
laboratory conditions. A. G. 
Some Remarks on Native Ferns. — G. von Beck ( Oesterreich . bot. 
Zeitschr., 1918, 67, 52-63, 113-123 ; see also Bot. Centralbl., 1919, 
140, 184). This paper brings together a quantity of morphological 
