672 SUMMARY OF CURRENT RESEARCHES RELATING TO 



generally localized in two distinct regions, and constituting the cyto- 

 plasm and the caryoplasm or nucleus. On contact with a foreign body 

 the cytoplasm takes on itself special characters, and becomes a dermato- 

 plasm or membranous layer. Cytodes are elements in which the 

 caryosomes are not grouped into a nucleus. The cell-membrane is 

 regarded by the author as always an intracellular derivative. 



The thallus springs from an isolated cell or spore. The body of 

 fungi is generally formed of cells reduced either to nucleus or to cell- 

 wall ; this structure is not properly non-cellular ; the author terms it 

 apocyty. A more highly organized type is the result of fecundation. 

 The elements of the embryo are differentiated from the first into an 

 epithele or epiderm and an apothelial mass. The epithelial body, 

 represented in mosses by the sporogone, is the point of departure of the 

 vascular body of the higher plants. Certain aberrant types of vascular 

 cryptogams, such as ferns, present a stage of suppressed embryo, the 

 oospbere giving rise directly to the vascular members ; this condition is 

 termed by M. Vuillemin apoemhrijoni/. 



In the portion of the work devoterl to the life of the individual, the 

 organs of fixation, support, and protection are first treated of, followed 

 by the phenomena of absorption and excretion. These two processes he 

 regards as opposites, the latter being concerned with everything which 

 the plant gives out to the environment, whether ponderable matter or 

 mechanical work. The author then deals with respiration, and the 

 functions of specific lives, which he classifies under renovation, multi- 

 plication, fusion, conservation, and dispersion. 



Under the head of the social life of plants are discussed the relations 

 between individuals of the same species, and especially the sexual 

 relations, and finally, the relations between individuals of different 

 species, including epiphytism, hybridity, grafting, parasitism, and 

 symbiosis, particularly the algo-lichen theory, and the phenomenon of 

 mycorhiza. 



B. CRYPTOGAMIA. 



Cryptogamia Vascularia. 



Psilotum and Tmesipteris.* — Dr. W. A. Haswell has carefully 

 examined the structure of Psilotum triquetrum and Tmesipteris tannensis, 



natives of New South Wales. 



Tmedpteris tannensis grows most commonly on the trunks of tree- 

 ferns, deeply buried in the fibrous coating of the stem, less often creeping 

 along the ground. The stem always branches dichotomouf^ly. It has 

 a central bundle of small scalariform and reticulated tracheides, without 

 any definite bundle-sheath ; but is surrounded by from one to four layers 

 of cells filled with a solid brown substance. In the leaf-bearing portion 

 the xylem jjortion is central, and is surrounded by phloem. The cortical 

 tissue is strongly sclerenchymatous in its outer part. The leaves 

 are oval and unsymmetrical at the base, with a single unbranched mid- 

 rib, which is produced at the extremity into a spine-like point. The 

 sporanges are borae on special lateral branches which terminate in bracts 

 similar to the ordinary leaves, but smaller. Each sporange has two 

 loculi ', the spores are oval and compressed. 



Psilotum triquetrum is shrub-like in habit, with very minute leaves. 



* Pr.jc. Liuu. Soc. N. S. Wales, ii. (1888) pp. 1025-31. 



