712 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Anatomy of Rutace.e. 



Rutaceae, Leaf-anatomy of. By Hilmar Schulze (Bcih. Bot. 

 Cent. bd. xii. ht. 1, pp. 55-98 ; 2 plates). — This is an important paper on 

 the anatomy of the leaf in Butacecs. The most important points are 

 connected with the secretion of mucilage by the inner walls of the 

 epidermis cells (of the upper surface). In the simplest cases the inner 

 wall (palisade side) has a mucilaginous layer deposited upon it ; in other 

 cases this latter becomes covered by a subsequent cellulose lamella ; 

 sometimes also a second deposit of mucilage and a second cellulose lamella 

 are laid down. Secretion glands were found in all the species in- 

 vestigated with one exception, in which only oil-cells were present. An 

 arrangement for emptying these glands was proved on the living plant in 

 the case of seven species, and in many others the anatomy pointed to some 

 similar structure. Peculiar circular groups of small cells were found on 

 the lower side of the leaves of two species of Boronia ; they are enclosed 

 by a ring of the usual epidermal cells, and are perhaps secretory in func- 

 tion. In Murray a exotica the epidermal cells are often pressed together, 

 sometimes to such an extent that the lumina vanish. Stone-cells were 

 found in the parenchyma of the main nerves in Almeidea. Idioblasts 

 were present in the mesophyll of the four species of Boronia examined, 

 and were at the extremities of the spiral vessels. Crystals of calcium 

 oxalate are found in the epidermis of Flindersia, and the walls of the 

 cells containing them are thickened. The large epidermis cells are often 

 divided into many small cells, of which each contains a crystaL 

 Hesperidin has been proved to exist in numerous other genera besides 

 Boronia. Seventy-six species, belonging to thirty-five genera, are dis- 

 cussed in this paper. — G. F. S.-E. 



Spore Development. 



Selaginella, Spore Development of {Beih. Bot. Cent. bd. xii. 

 ht. 2, pp. 182-199 ; 1 plate).— Dr. P. Denke (Krefeld) has followed the 

 development of the spores. He fixed the material in J glacial acetic and 

 | absolute alcohol, then hardened in 50-60 per cent., 70 per cent., 80 per 

 cent., 95 per cent., and absolute alcohol ; then in chloroform and 

 paraffin. The sections were 5-7*5 \x thick, and Meyer's Eiweiss glycerin 

 was employed. Stained hematoxylin and Congo red. 



The epidermal cells of the stem at a point just above the leaf divide, 

 and the sporangia are formed by them and the hypodermal tissue. The 

 author did not find that one special cell, characterised by great size,, 

 became the spore mother-cell. The macro- and microsporangia develop 

 in the same manner until the separation of the cells of the central 

 tissue in the sporangium ; this suggests that they are phylogenetically 

 of the same origin. An extranuclear spindle initiates the division of 

 both macro- and microspore mother-cells. The nucleus is drawn into 

 the spindle by fibrils passing from the spindle poles to the nuclear 

 membrane. Kxo- and mesospore of the macrospore are close together, 

 and are both formed one after the other by the protoplasm of the mother 

 cell. During this process the membrane of the mother-cell becomes 

 dissolved. After mesospore formation, there is only a small sphere of 



