94 DIVISION I. — GENERAL MORPHOLOGV. 



begins an extremely thin lamella of the wall, not previously distinguishable, suddenly 

 splits off at the apex of the ascus, and the inner lamella issuing through it lengthens 

 in a few seconds into a tube nearly three times as long and as broad as or broader 

 than die original ascus; the lower part of the tube continues to be attached to the 

 torn outer lamella (Fig. 46 A). The wall of the elongated tube is of about the same 

 thickness as that of the original ascus-wall. The eight spores follow pari passu 

 the apex of the elongating tube, keeping as nearly as possible their original grouping, 

 the uppermost one being close to the apex. ' Soon the uppermost spore is seen 

 to have moved into an aperture which has formed in the terminal point of the tube 

 and then to be ejected through it with great force. As soon as this has happened, 

 the tube shortens by about half the length of a spore, so that the second spore 

 now touches the point of the tube and is pressed into the aperture, which it stops 

 up. Then the tube elongates again to its original length and the second spore 

 is then ejected with the same force as the first.' The entry of all the remaining 

 spores into the opening and their successive ejection is accomplished in the 

 same manner. Finally the empty tube, which is open at the apex, contracts rapidly 

 to about ^ of its length while the membrane continues to swell considerably, and 

 eventually becomes disorganised without undergoing further changes. The whole 

 proceeding occupies only a space of a few minutes. It is evident that we have 

 in this case a modification of the discharging mechanism, the chief point in which must 

 be that the width of the apical aperture is too small for a simultaneous discharge of the 

 spores ; but the question requires further investigation. 



Successive ejection is at present certainly known only in a few Pyrenomycetes. 

 That it should occur also in the open hymenia of Discomycetes is not probable ; a 

 brief statement of Crouan 1 about Vibrissea can scarcely be used here, and moreover 

 needs confirmation. In the Pyrenomycetes with which we are concerned here the 

 asci, like those represented in Fig. 44, are packed close together at the bottom 

 of perithecia with a narrow canal-like orifice, and when they elongate they thrust them- 

 selves one after another through the canal without becoming detached from their 

 insertion till their upper extremities are free from the perithecium, and then ejection 

 takes place. Woronin was the first who described these proceedings correctly in 

 Sphaeria Lemaneae 2 . His account holds good also of Sphaeria Scirpi, Phyllachora 

 llini, and Cordyceps militaris. The tops of the asci may be seen emerging one after 

 another from the ripe perithecia of the latter species in a damp atmosphere, and 

 ejecting their spores. Each rises about six times its own diameter above the mouth 

 of the perithecium ; in a few minutes the slender filiform spores fly one after another 

 with the speed of an arrow from the tip of the ascus; each of these successive 

 ejections is followed by a slight but permanent shortening of the ascus, which 

 reaches the level of the orifice of the perithecium as the last spore- is eje< ted. 



The ejection of spores from the perithecia of Claviceps, which was observed 



by Tulasne 8 and may be seen with the naked eye as a puffing out of fine minute 



glistening needles, is undoubtedly produced in the same wayas in Cordyceps, and my 



lanation of it at page 145 of my first edition was in the main incorrect. It would 



appear from the accounts which we possess that the same or similar processes are 



1 Ann. d. sc. oat. ser. 4, VII, p. 176. • Beitr. HI, p. 5. 3 CaipoL I, p. 42. 



