40 KEY TO BRITISH RUBI. 
position (fig. 5). All degrees of this change may be met with, the 
most remarkable perhaps being one illustrated by Mr. Worthington 
Smith in the Gardeners’ Chronicle for Feb. 24, 1887, in a species of 
Russula, where three adventi- 
tious pilei sprang from the top 
of the normal one; of these, 
two were reversed, whilst the 
third had the gills turned down- 
ward in the ordinary manner. 
See also Mr. Smith’s article in 
Gard. Chron., July 26, 1873. 
t will thus be seen that 
these cases of inversion are 
numerous, and cannot be at- 
Fig. 5.—Mushroom with a second one outgrowths from an already 
owing from its pi i i : 
ero foom its pllens in am icolatod  commpleted structure, the diffe 
natural position. rentiation of the tissues often 
takes place in an inverted 
direction, and furnishes additional evidence in support of the 
that there is no fundamental difference between caulome 
and phyllome. 
In other cases the inverted position seems to be due to a 
reversion to a primordial or even to an aucesiral state of things, 
but what brings about this sudden resumption of pristine ways is 
an utter mystery. 
AN ESSAY AT A KEY TO BRITISH RUBI. 
By tHe Rev. W. Movie Rogers, F.L.S. 
(Concluded from p. 10.) 
. R. coryirrotrus Sm. — Near R. dumetorum, but with st. 
while in the typical plant (R. sublustris Lees) the term. lt. is con- 
spicuously different in outline. Pan. somewhat irregular, more or 
less corymbose, often with 2 or 8 long axillary branches; rachis 
and ped. grey-felted, sometimes quite eglandular, and seldom having 
more than a few sunken or very shortly stalked glands (chiefly at the 
