368 MR. C. B. PLOWRIGHT ON THE REPRODUCTION 



F\<*. 7. Flattened expansion produced by cultivation from an arrested sporan- 

 gium ; growth, with a wedge-shaped apical cell, appears to be pro- 

 gressing at more than one point. X 130. 



Plate XII. 



Fig. 8. Part of a pinnule of Athyrium F.-f. clarissima, with vascular bundles 

 (vb) and one sorus. Cultivation for five weeks has resulted in the 

 development of prothalli from some of the arrested sporangia ; these 

 prothalli bear antheridia and archegonia, but are still attached to the 

 pinnule which bore them. X 40. 



Tolystichum annulare, var. pulcherrimum. 



Fig. 9. Apex of a pinnule which has grown out into a flattened expansion one 

 layer of cells in thickness ; this has not, however, as yet the distinc- 

 tive characters of a protliallus. X 20. 



Fig. 10. Apex of another pinnule, which has grown out into a flattened expan- 

 sion of considerable size ; this expansion has the characteristic struc- 

 ture of a prothallus, with marginal glandular hairs and thickened 

 cushion ; the latter bears on its under surface organs which proved, on 

 cutting sections of the prothallus, to be mature antheridia and young 

 archegonia. X 20. 



Fig. 11. One mature antheridium from a section of the prothallus shown in 

 fig. 10; it has not yet ruptured. x325. 



Fig. 12. One archegonium from a section of another specimen; it has passed 

 the period of maturity without the neck having ruptured ; the egg-cell 

 has become disorganized, x 325. 



Remarks on the Reproduction of the Hetersecious Uredines. 

 By Charles B. Plowhight. (Communicated by W. T. 

 Thiselton Dyer, C.M.G., M.A., F.R.S., F.L.S.) 



[Head 6th November, 1884.] 



The object of the present note is to draw attention to a point 

 concerning the reproduction of the Hetenecious Uredines when 

 this takes place without the intervention of the fficidiospores, 

 which has apparently hitherto escaped notice. This simply is 

 that, when the heteraecious species reproduce themselves without 

 passing through the secidial stage, the resulting uredospores are 

 far more abundant than in the case when they arise from the 

 implantation upon the host -plant of the Jecidiospores. 



My attention was first drawn to this in the summer of 1883, 

 by some specimens of wheat received from two districts in 



