190 SALMON : SUPPLEMENTARY 
in the wall being somewhat rough (‘‘ alquanto verrucosa’’). The 
conidia I have seen measure about 30-35 x 12-15 4, and have a 
smooth wall, although, as is generally the case with the conidia of 
the Erysiphaceae, very old conidia, through the wrinkling of the 
cell-wall, or through incrustation, appear falsely to be rough. 
The fungicides, recommended for the “ pea mildew”’ above, 
should prove efficacious here. 
Comes (13*, p. 246) also records cases of the tomato being 
seriously affected by the present species, and remarks, ‘In 1879 
the tomato was attacked by it at Palermo. The plants presented 
grayish spots, which by degrees became black, both on the skin . 
and on the leaves. Microscopic examination showed the presence 
of an Erysiphe, very similar to the preceding [Z. Marti}, but fur- 
nished with the characters of £. communis. In 1881 it injured the 
tomatoes in the region of Salerno, and in other localities of north- 
ern and central Italy. Moreover, this disease has been known in 
the region of Palermo for twenty-five to thirty years under the 
name of male nero; it attacks the plant at all seasons, but more 
readily about the beginning of May. The cultivators think that 
it is caused by excessive dampness, since the plant, cultivated 
under dry conditions, is exempt from it. They are convinced that 
the disease is contagious, and consequently if they observe that 
the disease appears in a nursery they destroy the affected plants 
immediately. They hold that sulphuring alone is useless ; they 
are accustomed, instead, to cut back the plants, to leave them dry, 
and then to sulphur them. When the disease appears before or at 
the commencement of flowering, they prefer to destroy the affected 
plants.” Tomaro (Le due crittogame che maggiormente dan- 
neggiano i pomidori; cf. Just’s Bot. Jahresber. 1891, 2: 245, 1893), 
has also reported the occurrence of “ £. communis’’ on the tomato 
in the neighborhood of Bergamo, and states that the disease was 
induced by excessive moisture, 
Var. seructa (Ell. & Everh.) Salm. (Monograph, p. 191) 
Distrib. add: United States of America, California, 7,000" 
(A. Purpus) in herb. Jaczewski. 
