656 SUMMARY OF CURRENT RESK ARCHES RELATING TO 



ultimate number of cells in the anthoridium varios a good deal oven 

 in the same species. Each of tho cells formed from the central 

 cells contains a nucleus, and tho antherozoids are formed directly 

 from the nuclei. The nucleus becomos indistinct, but does not 

 actually disappear ; as soon as it is again distinctly visible, it has 

 increased in size and has becomo curved ; not only these curved 

 nuclei, but the sperm-cells themselves, increase so greatly in size that 

 the parietal cells are almost obliterated. The antherozoids escape 

 by tho dissolution of the division-walls. Thoy remain for a few 

 moments after their escape enclosed in the remains of tho wall of 

 the mother-cell, but this is soon raptured, and the antherozoid swims 

 rapidly away, dragging after it the remains of the contents of tho 

 mother-cell as a very delicate vesicle. 



Muscineee. 



Assimilating System of the Sporogonium of Mosses.*— Dr. G. 

 Ilaborlandt points out that in most Bryinere the sporogonium has a 

 moro or less perfect assimilating system, situated generally in the 

 innermost layer of the wall of the capsule, and the peripheral paren- 

 chymatous layers of its neck, especially in the latter when well 

 developed. Examples are furnished by Phascomitrium pyriforme, 

 Funaria hygrometrica, Bryum argenteum, Weber a elongata, Meesia 

 longiseta, and Tayloria serrata. The same function is performed by 

 the apophysis of most species of Splachnim as long as it is still 

 green. The assimilating tissue is a palisade- or spongy pai*enchyma. 

 It is marked by the presence of stomata, which are absent where this 

 tissue is wanting, as in the Sphagnaceae and Andrereacea?. The 

 amount of chlorophyll contained in this tissue is very considerable. 



Formation of Pits in Mosses.f — Herr K. G. Limpricht states, that 

 in all the European Sphagnacere there are simple pits in the wood- 

 cells and medullary cells of the stem and branches, and that they are 

 especially abundant at the spot from which springs a tuft of branches ; 

 they are found also in the septa of the swollen cells at the base of 

 the leaves. Septa with sieve-like thin spots, rudimentary sieve- 

 plates, occur in the stem and branches of Sphagnum, in the transverse 

 section of many species, as S. contortum and squarrosum, both in the 

 spongy outer cortex and in the woody and medullary layers. These 

 thin spots are often ranged irregularly, in other cases in radial 

 rows. 



In the true mosses, simple pits are a widely spread phenomenon, 

 not only in the axis, but also in the leaves ; in the thin-walled cells 

 of the conducting bundles they appear to be wanting. The author 

 finds them in great abundance in the stem of Andresea, Dicranum, 

 Grimmia, Bacomitrium, Bryum, Philonotis, Breutelia, Webera, Mnium, 

 Bartramia, Hypnum, &c. In the mid-rib of the leaves they are 



* Flora, lxix. (1886) pp. 45-7. 



t JB. Sclilos. CJesell. Vaterl. Cultiir, lxii. (1885) pp. 289-90. 



