Fan, 26, 1871] 
NATURE 
243 

We propose here to give a short account of the con- 
tents of the present number. The first paper (by Dr. J. 
Schroeter) is on the parasites of the genus Syuchytrium. 
The Syachytria form a small group of parasitic crypto- 
gams, remarkable for their peculiar mode of development 
and the absence of any mycelium. They produce small 
swellings, or “ galls,” on the plants in which they occur; 
but in comparison with other parasites cause little injury 
or distortion. The genus was established by De Bary 
and Woronin in 1863 for the reception of the plant now 
known as Syuchytrium Taraxact. Several other species 
have since been discovered, the number of those described 
by Dr. Schroeter in the present paper amounting to 
eleven. The plants were divided by Woronin into two 
groups. In the first the protoplasm of the cells is 
white, and the zoospores pass at once into the condition 
of resting spores. In the second group the protoplasm 
is reddish, and the zoospores, attaching themselves to 
living plants, produce spherical masses of zoosporangia 
until the close of the vegetative period, when they produce 
resting spores. Dr. Schroeter proposes three groups, 
which he calls Lusynchytrium, Chrysochytrium, and 
Leucochytrium. The first corresponds to Woronin’s 
second group, the second to Woronin’s first group, and 
the third comprehends certain Syuchytria which agree 
with those of Woronin’s first group except in having 
white protoplasm. Dr. Schrceter describes the species 
with great care, and in considerable detail, and the 
descriptions are for the most part illustrated by excellent 
plates. He considers the genus to be one of wide distri- 
bution. With regard to its systematic position, there has 
never been any doubt that Syzchytrium belongs to the 
Chytridiacee, but whether the latter are fungi or algz is 
not so well settled. The conclusion at which the author 
has arrived is that they should be“placed as a distinct 
family amongst those Padmellacee which produce zoo- 
spores, being nearly related to Hydrocytium, Codiolum,and 
their allied genera. 
In the second paper (“Ueber die Faule der Cactus- 
stamme ”) MM. Lebert and Cohn describe a new species of 
Peronospora, which was most destructive to a collection 
of cactuses, affecting particularly Cereus giganteus and 
Melocactus nigrotomentosus. Theepidermis of the cactus 
was not materially altered, but the cellular tissue beneath 
became entirely rotten, the decay beginning with the 
’ inter-ceilular substance : so that the parenchymatous cells 
were easily separable from one another. The contents of 
these cells became brown, and the cell-membrane almost 
entirely dissolved, the cactus thus exhibiting an internal 
state of decay similar to that seen in diseased potatoes. 
The fungus is closely allied to the potato blight, Pevono- 
spora infestans, which it resembles in having the hyphz 
only slightly ramified, not dichotomous and therefore pro- 
ducing but few conidia, as well as in its delicate my- 
celium (which has no suckers) and in the swellings under- 
neath the large, beaked conidia. The authors suspect that 
the fungus must have been imported with the cactuses 
from America. 
The third paper, by Dr. Cohn, is entitled “ Ueber eine 
neue Pilzkrankheit der Erdraupen,” and contains a detailed 
account of a fungoid disease affecting the caterpillars of 
Agrotis segetum. The skinturns black, a coal-black pig- 
ment appears in the blood, and the caterpillar becomes a 


wrinkled and brittle mummy. Upon examining the in- 
terior the whole cavity of the body, except the intestinal 
canal, is full of a black tinder-like substance, consisting 
of very large, dark brown spores, which are globular, but 
sometimes wrinkled at the surface, so as to present a 
crenate outline under the microscope. Contemporaneously 
with the colouring of the blood, cylindrical or curved 
tubes (Sch/auche) are seen, which become divided by septa, 
and form rows of cells which separate from one another 
and appear in the blood as free globular or oval cells. 
These Dr. Cohn calls gontdia. These gonidia germinate 
shortly before the death of the grub, and produce a my- 
celium which displaces the inner organs, except the 
intestinal canal and the trachez, and fills the hollow of 
the body. This mycelium produces partly new gonidia 
and partly the dark spores already mentioned. The latter 
are probably resting-spores, as it seems from Dr. Cohn’s 
observations that they do not germinate until the spring. 
The fungus (to which the author gives the name Zarz- 
chium) appears to be generically the same as Fresenius’s 
Entomophthora, and to be closely allied to Empusa. 
Dr. Cohn thinks it not improbable that Awpusa and 
Tarichium are stages of development of the same fungus ; 
that A7zfusa may be the conidial form of a fungus of 
which TYarichium represents the teleutospores. If so, 
Empusa bears the same relation to Zarichiumas Oidium 
does to Erysiphe, Uredo to Puccinta, and (perhaps) as 
the efzphytal conidia of Peronospora to the enxdophytal 
oospores. 
We have but little space to notice the two remaining 
papers. One is by Dr. Schroeter, and relates to a disease 
affecting Pandanus, which was observed many years ago 
by Sinnig, the Inspector of the Botanic Garden at Pop- 
pelsdorf, and which has since been investigated by Bouché, 
at Berlin. In the spring of the present year it attacked a 
splendid specimen of Pandanus odoratissimus, Jacq., in 
the gardens at Breslau ; the branches decayed, and it was 
found necessary to cut off the crowns, afterwards the 
branches themselves, and eventually the greater part of 
the entire plant, leaving only a portion of the stem and a 
single branch. A strict investigation afforded no ground 
for supposing that the disease had been produced by 
cold, drip, or other causes which would suggest them- 
selves to cultivators, but a fungus was discovered 
identical with one described by Leveillé as long ago as 
1845, which occurred in the Botanic Garden at Paris 
upon Pandanus, and which he called Melanconium 
Pandan (Ann. d. Sciences Nat. ser. iii. t. 3, p. 66). The 
Melanconium in the present case was accompanied by a 
Nectria, which Dr. Schroeter considers to be the Wectria 
Pandani, Tul., and conidia were also observed, the 
mycelia of which exhibited the forms of Tudercularia, Stil- 
bum, and Verticillium or Penicillium, The author con- 
siders it extremely probable that the M/e/anconium, the 
Nectria,and the conidia are produced from the same myce- 
lium, the fungus thus exhibiting the following forms of 
fruit :—1. Grey-green conidia (ze. the Melanconium fruc- 
tification). 2. Colourless conidia, the supports of which ° 
assume three different forms, viz. (a) Zudercularia, (6) 
Stzlbum, (c) the form of such moulds as Verticillium or 
Penicillium. 3. Spores in asci formed in orange-red peri- 
thecia seated ona Stroma. : 
Dr. Schroeter concludes that there can hardly bea doubt 
