PORTULACEX, AND THEIR ALLIES. 63 
Linnean character of 5 instead of 10 stamens is said not to be 
quite constant; but I have always found 5 only in the few speci- 
mens I have examined. 
Acanthophyllum and Drypis, with a general affinity to Sapo- 
naria, are closely connected with each other in their prickly 
foliage, bracts and calyx-teeth, in their ovary and fruit. The 
ovules are few ; and of these few, seldom more than one attains 
maturity. The capsule has been described as circumsciss, but in 
most cases that dehiscence has appeared to me to have arisen from 
the manner in which the specimens had been dried. In many 
. Sileneæ the upper portion of the capsule assumes a more cartila- 
ginous and stiffer consistence than the lower part; in these two 
genera it is particularly thick, and opens in valves only very late 
or not at all, whilst the lower portion, especially if gathered before 
it is quite ripe, remains thin and herbaceous, so as to break from 
it with very little force, but I have never seen the upper portion 
fall off naturally. The characters by which the two genera are 
distinguished are more artificial. Acanthophyllum, containing 
about a dozen species, has a 5-angled or 5-ribbed calyx, either 
without any lateral nerves, or one faint one to each sepal, on each 
side of the midrib; the stamens are usually 10, and the styles 2. 
In Drypis, still limited to the old Linnean species, the calyx has 
many ribs, with those of adjoining sepals usually free from 
each other as in Dianthex, not united as in Silene and Lychnis ; 
the stamens are usually 5, and the styles 3, although I have not 
unfrequently observed 2 or5 styles. Jordania of Boissier appears 
to have the general characters of Acanthophyllum, without sufti- 
cient difference in habit to maintain it as a distinct genus on 
account of the capsule more readily splitting into 4 valves. 
Gypsophila and Saponaria, again, are too closely blended with 
each other to suffer any positive line of distinction to be drawn 
between them, a few of the smaller-flowered species being almost 
equally referable to the one or to the other; yet, as old-established 
and rather numerous groups with a great majority of well-charac- 
terized species, they may still be maintained as separate genera. 
With the seeds, the 10 stamens, and other general characters of 
Silene and Lychnis, they are readily known by the calyx, in which 
the lateral nerves of adjoining sepals, if present, never amalgamate, 
and by the styles, which are almost if not quite always two only. 
They differ from each other chiefly in the calyx, which in Gypso- 
Phila is usually turbinate or campanulate, not contracted at the 
top, with 5 usually broad nerves, and is more or less membranous 
