Notes. 
343 
Aspergillus niger (Nat. Coll. Type Cultures No. 594). No change in branch 
intervals in 7^ hours ; hypha grew 250 g. 
Penicillium expansum (Washington 4189 ; Nat. Coll. Type Cultures No. 593). No 
change in branch intervals in 47 hours ; four hyphae observed, of which one 
grew 719 /A, in g\ hours. 
Pyronema confluens (Birkbeck : Nat. Coll. Type Cultures No. 1245). No change 
in segments in 24 hours; two hyphae observed; mean length of segments, 
39-7 [x ; mean length from tip to nearest septum, 136*9 /a; one hypha grew 
1,001 /x. 
Rhizoctonia solani (Jersey potato; Nat. Coll. Type Cultures No. 1007). No 
change in segments in 56 hours; two hyphae and five branches measured ; 
mean length segments, 151-7 /a; mean length tip to nearest septum, 179*6 /a; 
one hypha grew 979 /a. 
Rhizopus nigricans (Roth. No. 13). No change in identifiable portions of hypha in 
44 hours ; hypha grew 4,149 /a. 
Botrytis cinerea. No change in segments in io-| hours; mean length segments 
(ten hyphae), 51*6 /a ; tip to nearest septum, 133 g ; one hypha grew 1,710 /a. 
With this organism the growth of aerial hyphae was also investigated, growth 
occurring also only at the apex. 
Fusarium (three species). 
1. No. 10 a a 4. No change in segments in 5 hours (two hyphae); mean 
length segments, 31*1 /a; tip to nearest septum, 138*5 /a; one hypha 
grew 176 /a. 
2. No. 13 c b b. No change in segments in 6-J hours; mean length segments, 
65*7 /a; tip to nearest septum, 179 /a; one hypha grew 1,288 /a. 
3. No. 18. No change in segments in 24 hours; mean length segments, 
58*8 /a; tip to nearest septum, 191-5 /a. 
Summary. 
These fungi ar^ representatives of widely separated genera, and in all it 
is found that the growth in length is purely apical, no appreciable elongation 
occurring in any part of the hypha other than the tip. This then would seem to be 
the general rule for fungi, though exceptions may perhaps occur. It may be con¬ 
trasted with what occurs in filamentous bacteria, where each of the segments expands 
equally at the same rate (Marshall Ward (2)), and in algae, where both types of growth 
occur, the purely apical and the intercalary (West ( 3 )). 
J. HENDERSON SMITH. 
Mycological Department, 
Rothamsted Experimental Station. 
References. 
1. Gwynne-Vaughan : Fungi. Cambridge, 1922. 
2 . Marshall Ward : Proc. Roy. Soc., 1895, vol. lviii. 
3 . West, G. S. : Algae. Cambridge, 1916. 
