64 
3 
petiole which .properly belongs to it. The latter is always the smallest 
petiole of any developed on the plant. 
The prickles of the Robinia have been explained as stipules, but 
never, so far as I remember, have those oi Xanthoxylum Aviericanuni. 
There are two prickles, one on either side of the 
petiole-scar, and, as a general thing, somewhat 
above the latter. Occasionally the thorns are 
scarcely developed, so that they can be traced 
only by the fibres belonging Xo them in the bark. 
These fibres, whether belonging to a developed or 
to a latent prickle, always run into the wood^ show- 
ing them to be not a mere product of the bark; 
and their situation would define them as stipules. 
Prickles or tliorns tlierefore may represent four 
different parts of a plant — the stem or a branch, 
the leaf or its ribs, mere emergences of the bark, 
and stipules. In Fig. A,;) is a node,^ is a branch, 
and ss are stipular prickles. Fig. B represents the 
bark removed to show the entrance to the vascu- 
lar fibres into the wood. 
DESCRirTiON OF FIGURES. — Fig. I. Flowering stem. 
Fig. 2. Non-flovveiing stem. Fig, 3. Abnormally divided 
root-stock Fig. 4. Leaf sheathing at c. Fig. 5. Section of 
sheathin'T base, 
A 
--t) 
v9 
P 
'V." 
Fig. 6. Vertical section. Fig, 7. The 
bud (^.) formerly sheathed by a leaf. Fig. 8. The sheathed bud developing for sev- 
eral years, a. Axillary bud. a. Developed axillary bud or branch, b. Terminal 
bud. 
Dayton, Ohio. 
Aug. F. Foerste. 
^Cidium Bellidis.— In a note upon this fungus in the Bulle- 
tin for March, 1884, p. ^2., I stated that I had produced it from the 
teleutospores of Piiccinia obsciira. Tliis Pucciuia^ however, occurs 
in the United States, specimens of it having been sent to me by Pro- 
fessor Farlow, who also informs me that the host-plant of the JScidi- 
nor cultivated in gardens, except very 
um IS 
neither indigenous 
rarely. It has been assumed by many persons, notably by some of 
those who write books upon botany, that the jecidial stage is abso- 
lutely necessary to the perpetuation of those species of uredines 
which possess it. This, however, is by no means true. Witness not 
only the presence, but profusion of the wheat-mildew {Puccinia 
gramtnis) \x\ districts where the barberry is very scarce, as in the fen 
country of Norfolk and Lincolnshire in England. The same is even 
more strikingly shown by the ravages of this fungus upon the wheat 
crops in Australia, where none of the barberries is indigenous. Im- 
pressed by these facts, I have given this matter some special atten- 
tion, for, living as I do upon the borders of the fen district it has been 
thought 
that a 
constantly brought under my notice. It has been 
single barberry bush could produce. ?ecidiospores enough to infect 
half a county, all that was necessary being a few stiff breezes to 
waft .the spores from the bush to the corn, miles away, in the same 
manner in which wx have been taught to believe the spores of P^' 
ronospora infestans were blown from one end of Europe to the other 
