564 THE AMERICAN NATURALIST. [Voı. XXXIX. 
illustrations of apogamy. Since Farlow’s discovery in 1874 of 
an asexual sporophytic growth from the prothallus of Pteris 
cretica the list of apogamous pteridophytes has steadily increased 
until now the phenomenon is known in perhaps 25 forms. Far- 
low's investigation was followed by an extended study of De 
Bary (78) on a large number of forms in the Polypodiaceze and 
resulted in the establishment of similar sporophytic outgrowths 
in Aspidium falcatum and Aspidium filix-mas cristatum. De 
Bary proposed the term apogamy (78, p. 479) for the general 
phenomenon and distinguished two forms, apandry the suppres- 
sion of the male sexual organs which results in a parthenoge- 
netic development of the egg, and apogyny for the suppression 
of the female. Sadebeck in the following year reported apog- 
amy in Todea one of the Osmundaceze (Schenk’s Handbuch der 
Botanik, vol. 1, p. 231, 1879) thus extending the phenomenon 
to another family. And later apogamy was found in 77icho- 
manes alatum one of the Hymenophyllaceze (Bower, '88) and 
in Selaginella rupestris (Lyon, :04, p. 287). 
The most important recent contribution on apogamy in ferns 
is by Lang ('98, abstract in Annals of Bot., vol. 12, p. 251). 
This paper presents an able discussion of the phenomenon in 
its relation to alternation of generations and adds the very 
interesting discovery of sporangia borne directly on prothalli that 
were grown from spores. These sporangia were found in clus- 
ters on a thickened lobe or process from the prothalli of Sco/o- 
pendrium vulgare ramulosissimum and Nephrodium dilatum 
cristatum gracile. The sporangia were perfectly normal in 
structure and they matured spores. It is probable that the. 
process is itself sporophytic in character, z. ¢., made up of cells 
with double the number of chromosomes of the true gametophy- 
tic portion of the prothallus, but cytological details are not 
known. Lang’s study of the apogamous development of sporo- 
phytic buds on several forms of the Polypodiacez is the most 
detailed work on apogamy in the pteridophytes yet published. 
The apogamous growths appeared as the result of cultures which 
were watered entirely from below and exposed to direct sun- 
light, important departures from normal conditions surrounding 
fern prothalli In all cases the prothalli developed normal 
