Brier ley .— The ‘ Endoconidia 9 of Thielavia basicola, Zopf. 491 
In only two or three cases has the mode of spore formation been 
developmentally observed, and then in but a cursory manner. On the 
other hand, in practically all, an endogenous origin of the spores by free cell- 
division within the ‘ endoconidial cell ’ has been assumed. 
The more accurately these Fungi have been investigated the more 
irreconcilable are the facts with any hypothesis having a true and continuous 
endogeny as its basis, and the more exactly do they accord with the inter¬ 
pretation I have given of the process of spore formation in Thielavia. This 
latter is not one of endospory or endogeny, and the terms ‘ endoconidium 
‘ endoconidial cell ’, and ‘ endoconidiophore ’ are misnomers. The formation 
of conidia is a process of acrogenous abjunction (‘ acrogene Abgliederung ’ x ), 
and it is only in the mechanism of their liberation that the peculiar character 
of these Fungi is seen . 2 
Summary. 
The conidia of Thielavia basicola are not endospores formed by free cell- 
division within an endoconidial cell. They are acrogenously abjointed from 
the conidiophore. 
The first conidium is liberated by the differentiation of its walls into an 
inner wall and a sheath, and by the rupture of the latter at its apex. 
The later conidia grow out through the sheath of the first, and are freed 
by the splitting of their basal walls. 
The formation of the transverse walls is by the ingrowth of a ring 
of cell-wall substance which finally closes in the centre. 
The process of conidial development seen in Thielavia is probably 
that of all 4 endoconidia 5 in Fungi. 
1 de Bary, A.: Comp. Morph, and Biol, of the Fungi, &c., 1887, p. 61. 
2 It is interesting to note that neither de Bary (loc. cit.) nor Zalewski (Ueber Sporenabschnii- 
rung und Sporenabfallen bei den Pilzen, Flora, 1883) mentioned these forms, although certain of 
them were well known at the time. 
Additional Literature. 
1. Bainier : Bull. Soc. myc. France, t. xjtiii, 1907. 
2. Berkeley, M. J. : Introd. Crypt. Bot., p. 327. 
8. Berkeley, M. J., and Broome, C. E.: Ann. and Mag. Nat. Hist., 1850. 
4. - 
5 
-: Ibid., 1854. 
- • Thirl 18*70 T 
6. 
• lUlUt j -L w / W JL • 
-: Gard. Chron., 1845, p. 540. 
7. Bomm et Rouss: Flor. Myc. Belg., p. 287. 
8. Boudier, E. : leones Mycol., t. iii, PI. 588, 589, 1905-10. 
9. Brefeld, O.: Mykologie, Bd. x, p. 188, Taf. v, 1891. 
