It is a variety of the American cocklebur, often
called sea-burdock, or the [140] hedgehog-burweed, a stout and common
weed of the western states. Its Latin name is _Xanthium canadense_ or
_X. commune_ and the form referred to is named by Mr. Cockerell, _X.
Wootoni_, in honor of Professor E.o. Wooton who described the first
collected specimens.
The burs of the common species are densely covered with long prickles,
which are slightly hooked at the apex. In the new form, which is similar
in all other respects to the common cocklebur, the burs are more slender
and the prickles much less numerous, about 25 to the bur and mostly
stouter at the base. It occurs abundantly in New Mexico, always growing
with the common species, and seems to be quite constant from seed. Mr.
Cockerell kindly sent me some burs of both forms, and from these I
raised in my garden last year a nice lot of the common, as well as of
the _Wootoni_ plants.
Spineless varieties are recorded for the bastard-acacia, the holly and
the garden gooseberry (_Ribes Grossularia_, or _R. Uva-crispa_). A
spineless sport of the prickly Broom (_Ulex europaeus_) has been seen
from time to time, but it has not been propagated.
Summarizing the foregoing facts, we have excellent evidence of varieties
being produced either by the loss of some marked peculiarity or by the
acquisition of others that are already [141] present in allied species.
Pages:
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152