348 BOTANICAL GAZETTE [ May 
had their terminal and segmental apices dilated into prothalli, which 
when layered ran the normal course, with the exception that resulting 
plants were invariably defective and depauperate. Here the sorus is 
eliminated, and the prothalli are produced altogether independently 
of the usual reproductive sites, by a modification of the tissue of the 
sporophyte. Several quite independent finds of the pudcherrimum type 
existed, and in every case apical apospory was found to be correlated 
with it, and furthermore soral apospory existed on the fertile fronds. 
The modifications of the life cycle, however, were not even yet 
exhausted, for curiously enough a sporeling of the apogamous variety 
of Lastrea above mentioned was found by the writer to bear a well 
developed prothallus at the tip of its first frond, and the second and 
third bore prothalli, even profusely, on their surfaces,a sort of pro- 
thallic rash as it were.* These produced a brood of plantlets, but one 
and all lost this aposporous character and assumed the merely crested 
type of the parent as their later fronds arose. Here as we have apogamy 
and apospory associated, the life cycle dwindles down to sporophyte, 
prothallus, sporophyte, the shortest possible cut except the bulbils on 
the fronds of viviparous ferns, which have no intermediate stage at all. 
Subsequently, the writer found both soral and apical apospory on 
another variety of Athyrium, and apical on a fimbriate form of Scolo- 
pendrium.? Curiously enough, subsequent to the discovery of the 
aposporous Lastrea, a sporeling of the same parentage originated in 
Mr. Cropper’s collection, which was and is profusely prothalliferous 
from all apices, the smallest piece of frond forming a mass of prothalli 
when layered, which creeps about Marchantia-like and yields a perennial 
crop of typical plants. Finally, in this connection, Professor Farlow 
found an aposporous (soral) type of Preris aguilina. Subsequently, 
at Professor F. O. Bower’s suggestion, Mr. W. H. Lang commenced a 
series of investigations in connection with the prothalli produced from 
spores of abnormal varieties, and thereby practically completed the 
series of abnormal modifications of the life cycle, by finding in more 
than one species prothalli bearing developed sporangia and spores,’ 
thus cutting out the sporophyte, and reducing the life cycle to spore, 
prothallus, spore, an absolute minimum. I must refer to Mr. Lang’s 
* DRuERY, C. T.: Jour. Linn. Soc. 29: 480-482. 1892. 
3 DrueEry, C. T.: Jour. Linn. Soc. 30:281-284. 1892. 
Lana, W. H.: Proc. Roy. Soc. 63:56-61. Phil. Trans. Roy. Soc. Ser. B. 190: 
ae 1898 

