318 PROF. F. 0. BOWER ON APOSPORY AND ALLIED PHENOMENA. 
example of sporal arrest, and substitution of а sporophoric bud in place of the sporangium, 
has been described by Goebel*; in these specimens of 1. lacustris and 1. echinospora, which 
grew at considerable depths in the Langemer lake, it appeared that the formation of 
sporangia was entirely arrested, and the energy of growth diverted into a different 
channel. As Goebel pointed out, this observation leads naturally on to those malforma- 
tions of the Phanerogamie ovule which are associated by Masters + under the head of 
Phyllody (Vergrünung). 
Under the third head, of Apospory, fall those cases in which the substitutionary growth 
following sporal arrest results in the formation of organs having the characteristics of 
the oophore. Starting with the Mosses, such developments have been induced from the 
sporogonium, by artificial means, by Pringsheim 1 and by Stahl$; by cutting the seta 
and capsule of certain Mosses into short lengths, and cultivating them on moist soil, they 
succeeded in inducing a formation of protonemal filaments directly from the sporogonium 
without the intervention of spores; the protonema thus produced ultimately formed 
Moss-plants in the ordinary way.  Pringsheim (2. c. p. 3) states that this protonema is 
derived from the fundamental square or endothecium (Grundquadrat), which normally 
gives rise to the archespore and columella; but Stahl (2. с. p. 692, &c.) states that in 
Ceratodon purpureus the formation is not exclusively from this part (Grundquadrat), but 
more especially from the third and fourth rows of cells from the surface of the wall of the 
capsule; it is to be noted, in connection with this, that in most cases of a similar growth 
from the sporangia of Ferns the archespore takes no part in the vegetative process. 
It was thus established by independent observations that in the Mosses exposure to 
extraordinary conditions may result in direct transition, by purely vegetative processes, 
from the sporophore to the oophore without the intervention of spores; a similar direct 
transition has now been found to occur in two of the Ferns above described, and the 
special interest attaching to the fact lies in this, that, at least in one case, the peculiarity 
has been traced in plants found wild, in districts far apart from one another; so that 
here the phenomenon is not artificially induced, but natural. A few'attempts have been 
made by laying portions of fronds of various Ferns, with immature sporangia on them, 
on moist soil, to induce apospory, as was done by Pringsheim and Stahl in the Mosses; 
hitherto these experiments have produced no result, but it is quite to be anticipated that 
if they be extended to a large number of Ferns, especially to those of a variable character, 
apospory may be induced with success in some of them. | 
It will be sufficient briefly to recapitulate the observations above detailed : in Athyrium 
F--f., var. clarissima, the substitutionary growths which accompany the arrest of spore- 
formation are restricted to the sporangium itself; by growth and division, especially in 
the superficial cells of the sporangia, irregular masses of cells are produced, which do not 
at first show the characteristic flattened form of prothalli, though the cells themselves 
are thin-walled and contain chlorophyll; these masses may attain considerable size and 
* Bot. Zeit. 1879, p. 1. T Veg. Teratology, pp. 262-271. 
t Monatsber. der Berliner Akademie der Wiss., July 10, 1876; also Pringsh. Jahrb. xi. p. 1, observed in Hyp- 
num serpens, Н. cupressiforme, and Bryum cespitosum. 
$ Bot. Zeit. (Nov. 1876), vol. xxxiv. p. 689, observed in Ceratodon purpureus, 
