ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 273 



of cells containing little plasma and no chlorophyll enclosed in an 

 epidermis containing abundant chlorophyll and serving as assimilatory 

 tisssue. An interesting feature is the intercalary growth connected 

 with the meristematic bases of the terminal pointed emergences ; by 

 this means both the leaves and the individual pinnae increase in length. 

 The stem is short, of irregular form, attaining a thickness of 1 ■ 5 cm. in 

 large plants. It has no distinct upper and lower surface, and it is 

 impossible to distinguish between root and stem, except at those places 

 where the remains of the old primary root are still visible. The tissues 

 are simple, without any distinct epidermis, and foreign bodies, e.g. 

 diatoms, are often embedded in it. Calcium oxalate glands are frequently 

 present. The structure of the primary root is at present unknown. 

 The functional roots are adventitious, with a smooth surface and a true 

 root-cap. Crystal glands are absent in the root itself, but abundant in 

 the root-cap. Chlorophyll is not present, so that these roots differ in 

 this respect from those of the Podosteniaceas, where the roots function 

 as assimilatory organs. 



CRYPTOGAMS. 



Pteridophyta 

 (By A. Gepp, M.A. F.L.S.) 



Embryo of Hehninthostachys.* — W. H. Lang publishes a study of 

 Hdminthostachys. 1. The embryo extends down into the prothallus 

 before segmentation takes place. The first two walls are transverse. 

 Of the row of three cells thus formed, the one next the archegonial neck 

 becomes the upper tier of the suspensor, and may become further divided 

 or not. The next cell forms the second tier of the suspensor, and becomes 

 further divided up. The terminal cell of the row forms the embryo proper. 

 2. This latter is at first straight, in a line with the suspensor. It becomes 

 differentiated into a hypobasal half giving rise to the foot, and an epibasal 

 half giving rise to the stem-apex, first leaf, and probably the first root. 

 The apex originates near the centre of the epibasal tier. 3. With 

 further growth the shoot becomes vertical and the axis of the embryo 

 curved ; and later this gives rise to the hypocotyl bearing the first .leaf 

 and stem-apex. The shoot is at first vertical, though dorsiventral in 

 construction, but later its apex bends over and growth proceeds horizon- 

 tally. 4. The author compares the Ma^attiaceEe, Ophioglossaceaj, and 

 seed-plants with reference to embryology, and suggests that the sus- 

 pensor represents the last trace of the filamentous juvenile stage in plant 

 history. 



Apical Growth and Branching in Selag'inella.f — A. Wand writes 

 on the apical growth and on the branching of Selaginella. He studied 

 six species, and finds that the apex of the main shoot is hemispherical, or 

 at any rate approximately so. That of the lateral shoots is parabolic. 



* Ann. of Bot., xxviii. (1914) pp. 19-37 (1 pi. and figs.), 

 t Flora, vi. (1914) pp. 237-63 (figs.). 



