CACTACEAE OF THE BOUNDARY. 
CORRECTIONS. 
A voyage to Europe, since my paper has gone through the press, has afforded me the advan- 
tage not only of the personal intercourse with numerous men of science and many cultivators, 
but also of an actual examination of various large collections of living cactaceae. Some of the 
results of my investigations, as far as they bear upon the Cactaceae of the Boundary, have been 
incorporated with the list of corrections of typographical errors. 
Page 2, line 22. Sepalis petalisque. It will scarcely be necessary to inform the reader that 
the numerous foliaceous integuments of the cactus-flower do not very properly range under the 
divisions of sepals and petals. For convenience sake, however, the exterior more herbaceous 
ones are called sepals, and the interior ones, with thinner texture and brighter color, are named 
petals. The ‘‘sepals’’ usually are more numerous than the “ pefals,’’ and, in most genera, 
form a complete transition from the organs, which on the stem, represent the leaves, (usually 
with their spiny appendages) to the petals. On the ovary they usually resemble the former, 
which, among other reasons, seems to give color to the suggestion of Zuccarini mentioned in 
the note to page 39, line 29. 
Page 2, note, line 10, omit or. 
Page 2, note, line 15: after found omit ,. 
Page 4, line 12: I follow De Candolle in giving, as one of the characters of the species, the 
number of the more distinct spirals of the tubercles in Mamillariae and cylindric Opuntiae, just 
as we describe the number of ribs of Echinocacti or Cerei. It is now well known that no 
character can be deduced from the direction of the spirals to the right or left. It is also known 
that the greater or less prominence of one or the other spiral depends on the number and 
crowded state of the tubercles and the comparative thickness and elongation of the axis. The 
characters deduced therefrom are not absolute, nor are they quite scientific. It would be more 
exact to state the phyllotactic law of the arrangement of the tubercles. I would have to say ~ 
that M. micromeris has its tubercles arranged after the }} or even the 74 system. But I sup- 
pose the plan followed by me is more intelligible to most readers, and not much less clear to the 
scientific phyllotaxist. 
Page 5, line 4. M. microthele is well distinguished from our species by its much larger 
tubercles and two unusually stout and short central spines. 
Page 5, line 36. The pale yellow spines look like the fibres of raw silk, and form a silk-like 
tuft, but are not tipped by a brush. 
Page 6, line 25, for pluribusve, read alterove. 
10! 
