CHAPTER III.—SPORES OF FUNGI. 67 
of which those named Cladosporium herbarum, Dematium herbarum’ and Alternaria 
are the best known; to these may be added the delicate heads of Myriocephalum 
botryosporum? and many others. 
Connected with these three kinds of acrogenous 
abjunction of spores is one which is less distinctly 
marked and which may be termed the mode of cross- 
septation (Querzergliederung). In this the terminal por- 
tion of a hypha or hyphal branch grows first of all to v 
a certain length, and then ceases to elongate but is divided 
by cross septa into a number of spore-cells. 
This mode of formation is seen most distinctly in 
the sporogenous branches of strong specimens of Oidium 
lactis? which rise into the air above the substratum. 
These branches have a cylindrical form and are many 
times longer than broad. When they have ceased to 
elongate they quickly divide by formation of cross septa 
into numerous cylindrical spores which are from one to 
two times longer than broad. In small specimens this 
cross-septation may extend over the whole plant, occur- 
ting even in the branches of the mycelium in the 
substratum. The formation of cross septa appears to 
commence in stronger individuals at the free apical 
extremity and to advance basipetally; but this point 
is quite as uncertain as the question, whether the sporo- 
genous branch consists at first of a number of longer 
cells which are afterwards divided into the short members 
by repeated intercalary bipartition, or whether the latter 
are the first divisions formed either simultaneously or 
successively and in basipetal order in the branch which 54, 34 Species of Altrnariz. a 
was up to the time of their formation unicellular; on and > sxtemitics of 2 | spor! 



hypha growing obliquely into the air 
these points further examination of the branches of fom @specimen grownon a mi i 
this Oidium is to be desired. Of similar character are 
the gonidial mother-cells of Syncephalis and Piptoce- 
phalis*, which spring simultaneously from the apex of 
the capitate extremities (basidia) of the sporophores and 
form a small clustered head. They have the form of 
elongated cylinders with rounded apices, and are divided 
after they have ceased to grow in length into several 
slide, zonthe4th Aug. at midday, dsome 
23 hours later; the two rows of spores 
which are still simple in a are branched 
ind. c a young sporophore on a my- 
celial filament submerged in water. The 
membranes of the pointed ovoid spores 
are yellowish brown where they show 
partition-walls in their interior and are 
colourless only at the upper pointed 
extremities, This is the case also with 
the youngest and still small spores, the 
sporophores and the mycelium. aand 5 
Magn. about 145, c 225 times. 
short cylindrical spores by transverse septa formed either simultaneously or succes- 
sively and in basipetal order, but always very rapidly. 

1 Low in Pringsheim’s Jahrb. VI, p. 494. Penicillium cladosporioides, P. viride, P. chlorinum, all 
of Fresenius (Beitr.), and P. olivaceum, Corda, are evidently the same form. Even if Tulasne’s view 
that the plant belongs to Pleospora herbarum is not confirmed, its connection with one of the allied 
Sphaeriaceae is more than probable. ? Fresenius, Beitr. t. V. 
3 Fresenius, Beitr.—Brefeld, Ueber Gährung in Thiel’s Landw. Jahrb. V, 1876, t. II. 
* De Bary und Woronin, Beitr. II. Brefeld, Schimmelpilze, I. Van Tieghem et Le Monnier in 
Ann. d. Sc. nat. Ser. 5, XVII, p. 370. See also below, sect. XLIII, Fig. 74. 
F2 
