CHAPTER V,—COMPARATIVE REVIEW.—ASCOMYCETES. 253 
It may be affirmed of the majority of the species which have just been con- 
sidered, that they are imperfectly known, because no attempt has been made to 
ascertain the entire course of their development. But some among them have not 
only been observed in the mature state or occasionally grown from the spores, but 
have been repeatedly submitted to long and careful observation and cultivation; and 
yet they are only known to produce the same supposed gonidial forms, and there 
is no sign of ascocarps or of any other member of the development, which 
the analogy of very similar forms in well-known species would have led us to expect 
from them. The large species, Aspergillus clavatus? for instance, has never been 
known to produce anything but gonidiophores; the sporocarps like those of Eurotium 
and Penicillium, which were to be expected from the structure of the gonidiophores 
and of the mycelium, never made their appearance either in Wilhelm’s many experi- 
ments in the artificial cultivation of the plant, which were made for the purpose 
of determining this point and were conducted under a variety of conditions, nor in 
many others which I have myself often repeated in the course of years. Botrytis 
Bassii? is a very common insect-destroying Fungus, which in the character of its 
vegetation is very like Cordyceps militaris, but resembles another Pyrenomycete, 
Hypocrea rufa*, in the way in which it forms its exposed gonidia; hundreds of 
cultivated specimens of the plant have produced only the same organs bearing 
gonidia, never a sign of perithecia ; my conjecture *, which has become an assertion 
in Brefeld *, with regard to the latter has proved therefore to be incorrect. The same 
must be said now of another insect-killing form which agrees very closely with 
Cordyceps militaris in the mode also of forming its gonidia, and which I have 
described under the name of Isaria strigosa®. Another instance which may be 
noticed here is the universally distributed and repeatedly cultivated Oidium lactis; 
this plant never produces anything but the mycelium with cylindrical serially abjointed 
gonidia’. ‘The common Cladosporium herbarum, Lk. also should not be forgotten 
in this connection. Further instances of this kind have been discovered in the course 
of the investigations which have been made into the pycnidia. I refer to Zopf’s 
account of Fumago of which a resume has just been given. Brefeld® cultivated a 
pycnidia-bearing form, a not uncommon parasite on the sclerotia of Sclerotinia, 
under very varied conditions through more than a hundred successive generations, 
without ever obtaining anything but the pycnidium-form. Similar results are 
recorded for other species in Bauke’s work on pycnidia; Ehrenberg’s Cicinnobolus, a 
parasite on Erysipheae*, may also be quoted here, and it may be added that the 
pycnidial forms mentioned here are so like others which undoubtedly belong to 
typical Ascomycetes, that they may be readily mistaken for them. 
In view of these facts of experience the question again arises which was 
discussed above in connection with the Mucorini and Peronosporeae whether we 
have before us species which are only imperfectly known to us, and which under 

1 Desmaziéres in Ann. d. sc. nat. ser. 2 (1834), II, tab. II. Fig. 4.—K. Wilhelm, Dissert. p. 62. 
2 See Bot. Ztg. 1867. ® Bot. Ztg. 1869, p. 590. 
° See Tulasne, Carpol. III. ' See above at p. 67. 
* Bot. Ztg. 1869, p. 590. ® Schimmelpilze, IV, 122. 
5 Schimmelpilze, IV, p. 136. ® Beitr. III, and above, Fig. 119. 
