perfectly wholesome.

The wild spikenard (_Aralia_) (Fig. 110, _F_), ginseng, and the true
ivy (_Hedera_) are examples of the _Araliaceae_, and the various
species of dogwood (_Cornus_) (Fig. 110, _J-N_) represent the dogwood
family (_Corneae_).

The second order (_Saxifraginae_) contains eight families, including a
number of common wild and cultivated plants. The true saxifrages are
represented by several wild and cultivated species of _Saxifraga_, the
little bishop's cap or mitre-wort (_Mitella_) (Fig. 111, _D_), and
others. The wild hydrangea (Fig. 111, _F_) and the showy garden
species represent the family _Hydrangeae_. In these some of the flowers
are large and showy, but with neither stamens nor pistils (neutral),
while the small, inconspicuous flowers of the central part of the
inflorescence are perfect. In the garden varieties, all of the flowers
are changed, by selection, into the showy, neutral ones. The syringa
or mock orange (_Philadelphus_) (Fig. 111, _I_), the gooseberry, and
currants (_Ribes_) (Fig. 111, _A_), and the stonecrop (_Sedum_)
(Fig. 111, _E_) are types of the families _Philadelpheae_, _Ribesieae_,
and _Crassulaceae_.

[Illustration: FIG. 111.--_Calyciflorae_ (_Saxifraginae_): _A_, flowers
and leaves of wild gooseberry, _Ribes_ (_Ribesieae_), x 1. _B_,
vertical section of the flower, x 2. _C_, diagram of the flower. _D_,
flower of bishop's-cap, _Mitella_ (_Saxifragaceae_), x 3. _E_, flower
of stonecrop, _Sedum_ (_Crassulaceae_), x 2. _F_, flowers and leaves of
hydrangea (_Hydrangeae_), x 1/2. _n_, neutral flower. _G_, unopened
flower, x 2. _H_, the same, after the petals have fallen away. _I_,
flower of syringa, _Philadelphus_ (_Philadelpheae_), x 1. _J_, diagram
of the flower.]

The third order (_Opuntieae_) has but a single family, the cacti
(_Cactaceae_). These are strictly American in their distribution, and
inhabit especially the dry plains of the southwest, where they reach
an extraordinary development. They are nearly or quite leafless, and
the fleshy, cylindrical, or flattened stems are usually beset with
stout spines. The flowers (Fig. 112, _A_) are often very showy, so
that many species are cultivated for ornament and are familiar to
every one. The beautiful night-blooming cereus, of which there are
several species, is one of these. A few species of prickly-pear
(_Opuntia_) occur as far north as New York, but most are confined to
the hot, dry plains of the south and southwest.