On the Morphology and Development of Phoma Richardiae n. sp. 
301 
moreover their walls may thicken only when cell division has ceased. 
They might therefore be regarded as abortive pycnidia. But, again, 
numerous cases are 
met with where the 
resemblance to deve¬ 
loping pycnidia is 
very slight, 
8. Changes in 
the pycnidial 
spores after ex¬ 
trusion. 
The pycnospores 
undergo various 
changes after they 
are extruded. As, 
however, the se¬ 
quence of events is 
difficult to follow in 
agar cultures owing 
to the massing of 
the spores, it will be 
convenient to des- 
crib g first tliG cbän— 
ges undergone under 4 - '• a ~ e ' Development of mycelial gemmae; 
°, 1 . , type a. — 2 — 5 : Mycelial gemmae; lype a. — 6 — 8: 
Other Circumstances. Mycelial gemmae; intermediate types. — g — 16 : Mycelial 
When a hanging gemmae; Type b. — 17 — 21 : Mycelial gemmae; Type c. 
drop of cane sugar — Development of Type c. — 24—27 : Mycelial 
solution is inoculated gemmae germinating. - (All = «*/,.) 
with a few spores, 
germination takes place readily and normal mycelium, bearing pycnidia, is 
formed. When a very large number of spores is used for inoculation 
their behaviour is very different. 
a) The majority swell up to several times their original size, and 
assume a yellow-brown colour, gradually thickening their walls. Some 
remain as large round, oval, or kidney-shaped single cells (Fig. 5, 1 — 4 ); 
a great many divide and grow further, forming small masses (Fig. 5, 
j— 12 ) or bands of cells (Fig. 5, ij — 16 ). They may push out short 
hyaline buds or tubes (Fig. 5, 6 —n). Not infrequently the products of 
two separate spores become united by short hyaline bridging tubes 
(Fig. 5, 12 ). It is convenient to designate these structures collectively as 
“spore gemmae“ 1 ). 
b) Round the edge of the drop groups of spores swell, and, remai¬ 
ning hyaline, become joined by short bridging tubes; from one of them 
chains of pear-shaped yellow-brown conidia similar to those produced on 
the aerial mycelium may arise (Fig. 5, ij, 18 ). This takes place especially 
where the spores happen to be very thickly massed around the edge. 
The chains are almost invariably directed outwards. 
1) Spores of Fitmago vagans behave somewhat similarly under the same conditions 
(vide Zopf, 1. c.). 
