232 
rOPULAE SCIENCE EEVIEIT. 
ferous ones occupying the centre, and the pistilliferous the cir- 
cumference. In both the perianth has four lobes ; the anthers 
are usually eiglit, arranged in a circle round a central column 
(fig, 8) ; the pistil is single, with a radiately-lobed stigma 
and an ovary adherent to the perianth, and imperfectly divided 
into compartments containing a great number of ovules (fig. 9). 
The sucker, or cone of attachment, is slowly developed and per- 
forates the bark of the Cistus; it possesses numerous spiral 
vessels, but no distinct vascular connexion with the stock occurs 
(figs. 6-7 ). This plant is the viroiaa-TLs of Dioscorides, in whose 
time the black juice, which contains gallic acid, was used, as it 
still is, as a styptic and astringent. 
As an example of the polystomal parasites Lathroea Squa- 
maria, a familiar British species, is figured (Plate C., figs. 1-4). 
This is to be found in early spring, on a diligent search, half 
hidden (whence its name) at the foot of hazels, elms, and other 
trees, in damp shady places. When fresh, the whole plant 
is white with a pink or purple tinge, and semi-transparent, but 
becomes perfectly black when dried.* It possesses a subterra- 
nean definite branched rhizome, from which the flower-branches, 
arise, and which is clothed with thick tooth-like scales, from 
the axils of some of which slender rootlets are given off'. The 
observations of Mr. Bowman in 1829 first showed that upon 
these rootlets were borne the absorbent tubercles (fig. 2). 
Careful washing away the soil will showthese attached to the root- 
lets of the supporting plant, and a section through both (fig. 3), 
displays a perforating cone, penetrating the bark at least, and^ 
as I am informed by ]\Ir. Stratton, actually pushing its way 
into the very wood. The singular fleshy scales of this plant, 
from which it has received its name of Toothwort, are, like the 
whole plant, very brittle ; they are of course homologous with 
leaves, and are remarkable for possessing in their interior nu- 
merous irregular cavities, on the walls of which are arranged 
stalked gland-like bodies (fig. 4). The allied genus, Clande- 
stina, possesses similar organs, the objects of which are not 
known. 
Of the genus Orohanclie^ which we may take to illustrate the 
polyrrhizal parasites, there have been described seventy or eighty 
species all having a strong family resemblance ; about ten of 
these are inhabitants of England, but their distinctions are ill- 
defined. The common 0. minor is a pest of clover-fields in some 
parts, being doubtless often sown with the crop, and doing con- 
* Immersion in spirit has the same effect, and the spirit becomes of a fine 
purple colour. Monotropa Ilypopitys behaves in the same way, and Dr. 
Lindberg suggests that the colouring matter may be indigo. See his- 
paper in ‘‘Journal of Botany,” 1873, p. 179. 
