408 
DODECANDRIA DODECAGYNIA. 
Class XI. 
6835 globiferum W. 
6836 montanum JV. 
6837 arachnoideum W. 
6838 monanthos W. 
globiferous 
mountain 
cobweb 
one-flowered 
Bot. mag. 507 
Plant, grass. 105 
Bot. mag. 
Bot. mag. 
History, Use, Propagation, Culture, 
curious. S. tectorum, common on the roofs of buildings, is used by country people as an application to burns, 
inflammations, and ulcers, alone, in a bruised state, or mixed with cream. Linnaeus informs us, that house- 
Class XII. — ICOSANDRIA. Stamens many, perigynous, or inserted into the Calyx. 
To gardeners this is one of the most interesting of the Linnean classes, containing a greater proportion than 
any other of objects which come within their observation and management. It also consists of genera for the 
most part naturally allied ; and comprises not only the most remarkable portion of Ficoideae, all Cacti, and the 
chief of the Myrtaceee, but almost every genus of the beautiful and hardy tribes of Rosacea. Its characters 
are well defined, and depend upon the insertion of a number of distinct stamens, exceeding twenty, into the 
inner surface of the calyx ; modifications of which organ are here found to be of more than ordinary import- 
ance in characterising the genera. 
The genera are extremely natural, and have been all studied with unusual attention. Some difference of 
opinion exists among botanists as to the limits which ought to be assigned to them, and great diversity of no- 
menclature has thence arisen. " But," as has been observed by a modern author, " in a class so strictly 
natural as this is, greater difficulty is always to be expected in finding characters for genera, than in those of 
which our knowledge is more imperfect, and whose series of individuals may therefore be considered less com- 
plete." In the apple and pear tribe, Pomaceee, where the greatest difficulty is thought to exist, we adopt 
Mr. Lindley's arrangement, as published in the Transactions of the Linnean Society, which we find admitted 
by all botanists of authority. 
But if it is difficult to ascertain the definite limits of the genera of Icosandria, it is yet more perplexing to arrive 
at a satisfactory conclusion respecting the species of which the genera are constituted. Having all been, as long 
as gardens have existed, the objects of cultivation, it has happened that many individuals have, under the 
action of domestication, wandered so far from their original types, as to have acquired new characters for them- 
selves, of so peculiar a kind as to have rendered it impossible at the present day to refer them with certainty to 
the source from which they originally sprung. To remedy this confusion, which has been thus increasing for 
ages, some persons have thought it necessary to distinguish the species by such artificial characters as they are 
now found to possess, without reference to any changes the genera may have undergone ; but it has been found 
that no facilities of discrimination have been gained by multiplying distinctions in consideration of differences 
which are neither permanent or remarkable, nor connected with natural habit, but purely artificial. To others 
it has appeared proper to endeavour to reduce the aberrant forms which now exist to those from which, upon 
mature consideration, they may be presumed to have been derived, and to simplify the arrangement and dis- 
crimination of the species by confining them within their primitive limits. As we think the latter to be the 
most simple principles of arrangement, and as they are certainly the most philosophical, we shall here follow 
those authors who have adopted them. 
It is usual in this class to distinguish the orders with two and three styles from that with five : but the dif- 
ferent species vary so much in the same genus in this respect, that we have only separated the genera into those 
with one style, Monogynia ; with two, three, or five styles, Di-Pentagynia ; and with many styles, Polygynia. 
Order 1. MONOGYNIA. Many perigynous Stamens. 1 Style. 
§ 1. Ovary inferior. 
1111. Cactus. Cal. imbricated. Petals numerous, in many rows : the mner the largest. Stigma many-cleft. 
Berry many-seeded. 
1112. Rhipsalis. Cal. 3-4-parted, very short. Teeth acuminate, membranous, very fine. Berry 1-celled, pel- 
lucid. Seeds 12, in the centre. 
1113. Bartonia. Cal. 5-cleft. Petals many. Caps, cylindrical, 1-celled at the end with 3-5 lid-like valves. 
Placentas 3-5, parietal, bearing seeds in a double row. 
