ZOOLOaY AND BOTANY, MICROSCOPY, ETC, 493 



according to the author, closed conducting cells rather than vessels. 

 The sieve-cells contain, as in all ferns, a clear watery fluid, with a 

 small quantity of fine-grained protoplasm on their walls. The struc- 

 ture of other parts of the sporophore is also described in detail. 



Pteris aquilina presents the same phenomena of continuity of 

 protoplasm as Struthiopteris ; and the contents of the sieve-cells are 

 also similar. 



Third Coat in the Spores of the Genus Onoclea.* — Mr. D. H. 



Campbell has detected the presence of a third coat in the spores of 

 the ferns Onoclea Struthiopteris and 0. sensibilis. After the detach- 

 ment of the exospore the spore is apparently covered only with a thin 

 transparent membrane, which, at the commencement of active growth 

 splits along one side, the true endospore protrudes in the form of a 

 root-hair at one end and the basal cell of the prothallium at the other • 

 the latter becomes again divided, and at this stage with a little care 

 the two lobes of the second covering can be clearly seen. These 

 lobes follow so nearly the lobes of the exospore, in those cases where 

 it remains attached, that it is then impossible to detect them. The 

 accessory covering was not detected in any other genera examined 

 but as in all cases the exospore adhered so firmly to the spore as to in- 

 terfere seriously with observations it is not impossible that it does 

 exist. 



Fructificatioii of Sigillaria-t — M. E. Zeiller describes the struc- 

 ture of the "cones" of several species of fossil Sigillaria and 

 Sigillariostrohus from the " terrain houillier." He comes to the 

 conclusion that the SigillaricB must be considered as belonging to the 

 Lycopodinese, and as forming a group intermediate between the 

 Lepidodendre^ properly so-called and the Isoetese. They present on 

 the one hand an affinity with Isoetes in the disposition of the 

 sporangia, and probably in the mode of dissemination of the spores ; 

 on the other hand with Lepidodendron in the constitution of the foliar 

 cicatrices, and in the anatomical structure of the stem. 



Muscinese. 



Movemeiit of Water in Mosses.l— Herr F. Oltmanns points out 

 that, in the case of those mosses which have no trace of vascular 

 bundles, as Hylocomium and Dicranum, the capillary rise of water 

 does not take place in the interior of the stem, although there may be 

 an osmotic current from cell to cell, but in the external capillary 

 apparatus formed by the stem and leaves ; there is also a complete 

 absence of transpiration. In Sphagnum the same purpose is also 

 answered by the large empty cells. In those mosses, on the other 

 hand, which possess a rudimentary vascular bundle, as Mnium and 

 Polytrichum, there is a limited amount of conduction of water in the 

 stem itself, as well as a feeble transpiration. It follows that mosses 

 have no power of extracting water from the soil, while they absorb 



* Bull. Torrey Bot. Club, xil. (1885) pp. 8-9 (5 figs.), 

 t Ann. Sci. Nat.— Bot., xix. (1884) pp. 256-80 (2 pis.). 

 J Oohn's Beltr. Biol. Pflanzen, iv. (1884) pp. 1-49 (2 pis.). 



