[ 801.) 
2 
XVI. On Apospory and allied Phenomena. By Prof. Е. О. Вотев, F.L.S. 
(Plates LVII.-LIX.) 
Read 16th December, 1886. 
THE term “ spore " has been, and still is, used in so different senses by different writers 
that it will be necessary, in treating a subject such as the present, to define clearly which 
of its various senses will be adopted in this paper. The choice lies between two definitions 
given by two eminent botanists, Sachs and De Bary ; the former, in his Textbook *, defines 
the spore, іп a restricted sense, as “either a direct product of fertilization (zygospore, 
оовроге) or the product of a vegetative act induced by fertilization ;” that is, starting from 
the Mosses and Ferns, he applies the term exclusively to those reproductive cells which are 
homologous with the spores of those plants, while to others which are not homologous he 
applies other terms. De Bary, on the other hand, gives a wider significance to the term, 
and applies it quite generally to “any cell which, as a single cell, becomes free, and is 
capable of direct development into a new organism (Bion), without reference to its origin 
and homology’’+. Since, іп the description of the phenomena to be detailed below, it is 
of importance to avoid any confusion of view by the introduction of discussions as to the 
homology of the various reproductive cells of the Thallophytes with the spores of the 
Archegoniatz, the narrower definition of the term, given by Sachs, will be adopted in this 
paper; but this is done rather with the object of clearing the ground of unwieldy discus- 
sion than as any expression of opinion as to the relative merits of the two definitions for 
purposes of general description. Accordingly, in discussing the phenomena of apospory, 
it will be understood that those cases only are taken into account in which the homology 
of the spores with those of the Mosses and Ferns is generally accepted 1. 
It is just ten years since Pringsheim § and Stahl || found, independently of one another, 
that it is possible, by cultivation under abnormal circumstances, to induce a formation of 
protonema by direct vegetative growth from Ше sporogonium of certain Mosses. In such 
cases there is an excision of the spore from the cycle of Ше“. Writing іп 1878, 
* 4 Aufl. p. 287. 
t Morph. und Biol. der Pilze, 1884, p. 139. 
+ Cf. De Bary, Morph. und Biol. der Pilze, pp. 130, 131. Compare also McNab, Proceedings of the Royal Dublin 
Society, n. s. vol. iv. part 9, p. 466 «с. е ; 
§ Monatsb. 4. К. Akad. Wiss. zu Berlin, 10 July, 1876; also Jahrb. fir wiss. Bot. Bd. xi. 1877, p. 1. 
| Bot. Zeitg. 1876, p. 689. Е 22 
«ГА peculiar abnormality is mentioned by Masters (Veg. Terat. р. 173). It was recorded as occurring in the 
Moss Encamptodon ( Weissia) perichetialis by Dr. Montagne (Ann. Sci. Nat. 1845, pp. 119 and 366, plate 14). In 
SECOND SERIES.—BOTANY, VOL. II. 97 
