208 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is very feeble. Injections are conducted mainly through the xylem, less 

 through the phloem, and to a limited extent through other tissues. The 

 rate of conduction varies according to the concentration of the injection, 

 the solution of least concentration travelling at the slowest rate. A few 

 fungi were able to conduct injections, but the algffi scarcely conduct any 

 of them, although a certain amount of diffusion may take place. It is 

 possible to trace the course of vascular bundles by means of injection. 



CRYPTOGAMS. 



Pteridophyta 

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



Phylogeny of the Pteroideae."' — F. 0. Bower, continuing his studies 

 in the phylogeny of the Filicales, discusses the Pteroidese. In summa- 

 rizing his results, he states that : 1. The gtelar ontogeny of Scldzaea and 

 Anemia starts from protostely {Lygodium), and shows successive steps 

 of stelar advance, namely, medullated monostele {S. pusilla and S. 

 rupestris) ; ectophloic siphonostely (-S. fl?ic^o/o/na) ; amphiphloicsiphono- 

 stely or solenostely {Anemiorrhiza) ; dictyostely {En-anemia and Mohria). 

 In Schizsea rupestris and S. digitata the sporangia are of marginal origin ; 

 and the later-formed indusium originates superficially below the spor- 

 angia. 2. Within the Fterideae of Prantl are two probably distinct 

 lines of phylesis — the first called " Pteridese bi-indusintae," the second 

 '' Pteridese uni-indusiatse." With the latter (Cheilanthoid) series the 

 present paper is not concerned ; the former (Pterid) series includes 

 Lindsaya, Psesia, Pferidium, Lonchitis, Histiopteris, Anopteris, Pteris, 

 Acrostichum, and is traceable from a two-lipped Dicksonioid origin. 

 3. Lindsaya has a primitive type of stele, and also has a fusion-sorus 

 which is actually marginal ; and the indusial flaps originate superficially 

 below it ; and the sporangia, at first gradate, later become mixed. In 

 Dictyoxiphium the fusion-sorus differs in the absence of the upper 

 (adasial) indusium. 4. The fusion-sorus of Pteridium is marginal in 

 origin, with two indusial flaps ; the gradate sporangia soon assume a 

 mixed condition. 5. Paesia has a, typical solenostele ; the marginal 

 sorus is usually two-lipped, but shows inconstancy of the inner (abaxial) 

 indusium. 6. Lonchitis is intermediate between the bi-indusiate types 

 and the genus Pteris. 7. Pteris {Histiopteris) incisa closely resembles 

 Pteridium in habit ; it is advanced as regards scales and venation, but 

 less complex in stelar condition. Its fusion-sorus fluctuates from 

 exact marginal origin, and the inner indusium is absent. The sporangia, 

 at first basipetal, become mixed. 8. Pteris (excluding Doryoptens) has 

 scales as well as hairs, is more or less solenostelic, has a single or double 

 strap leaf -trace, and reticulate venation. The fusion-sorus is superficial 

 in origin ; and the inner (abaxial) indusium is absent. The succession 

 of sporangia is mixed. In all these characters there is an advance 

 from the Lindsaya- Psesia type. 9. Acrostichum praestantissimum and 



* Ann. Bot., xxxii. (1918) pp. 1-68 (43 figs.). 



