i 
[Crown Copyright Reserved. 
ROYAL BOTANIC GARDENS, KEW. 
BULLETIN 
OF 
MISCELLANEOUS INFORMATION. 
No. 2] | [1917 
VI.—THE BRITISH SPECIES OF PHOMOPSIS. 
W. B. Grove. 
(With Plates.) 
Saccardo, in his Sylloge, 1884, vol. ili, p. 66, suggested that 
one of the sections into which the vast genus Phoma could con- 
veniently be subdivided might be called Phomopsis— perithecio 
subastomo depresso, basidiis demum uncinatis’’—and added that 
the species of this section were probably all spermogonia of the 
ascophorous genus Diaporthe. At that time the real basis of 
this subdivision was imperfectly understood; it has since been 
worked out more fully, especially by. Diedicke (Annal. Mycol., 
1911, ix. 8), and it is now seen that, so far from being a section 
of Phoma separated by only slight differences, Phomopsis is in 
fact a very distinct genus with well-marked characters. 
The typical pyenidium of Phoma is somewhat globose or lens- 
shaped, thin-walled, formed of rather loose olivaceous-brown or 
blackish pseudoparenchymatous tissue, which is only one or two 
cells thick and surrounds the pyenidial cavity similarly on all 
sides. It has a more or less marke ti be or pore, often 
papillate, through which, when placed in water, the mature 
spores issue in those long curling strings with which all micro- 
mycologists are familiar, while the sporophores are very short, 
oftentimes barely perceptible or in age totally obsolete. 
The typical Phomopsis, on the contrary, is rarely or never 
globose, when mature, and has the internal cavity enclosed by 
a heterogeneous wall; for it is floored below by a “‘ proliferous 
stratum ’’ several cells thick, composed of very minute faintly- 
coloured cells, while the upper half, in its perfect state, is roofed 
a dense layer, also many cells thick, of very dark minute 
closely-packed cells, pierced usually about the summit by an 
ostiolar passage, often wide and irregular, which does not allow 
the spores to issue forth in curling tendrils with the same regu- 
larity as in Phoma. The sporophores which line the interior 
are long, flexuous, subulate, -acicular, or cylindrical, densely 
crowded and much more permanent than those of Phoma; many 
of them, in fact, can always be seen under the microscope with 
the single apical spore still attached. The spores are lanceo- 
late- or oblong-fusoid, more or less acute at the ends, hyaline, 
(4978.) Wt. 152—699. 1,125. 7/17. J.T. &S., Ltd. G14 Sch. 12. 
