PAEASITISM IN FLOWERINa PLANTS. 
233 
siderable damage. Still more harmful in some parts of France 
is the 0. ramosa, parasitic on hemp chiefly, and the subject of 
the illustration Plate XCIX., figs. 5-9. Their habits were known 
to antiquity, as the name Orohanche {ay-)(SLv^ to strangle), which 
dates from Dioscorides, denotes. Turner, the first English botani- 
cal author, describes in 1562 his discovery of the clover species, 
thus : — He noticed an Orobanche by the side of a “ common 
claver or medow trifoly which was all weathered, and when I 
had dragged up the root of the trifoly to see what shulde be 
the cause that all other clavers or trifolies about were green 
and freshe that that trifoly should be dede, I found the rootes 
of orobanche fast clasped about the rootes of the claver, whicli 
as I did plainly perceive did draw out all the natural moisture 
from the herbe that it should have lived withall and so killed, 
it” (Herball, pt. ii. f. 71). The aspect of the various species 
is very similar ; a spike of rather showy flowers on a brown erect 
stem, with scattered scales more numerous at the base, which 
is swollen and possesses a single large sucker, attached usually 
laterally to the extremity of a rootlet of the victim. Around 
this, from the bulbous base of the axis arise numerous thickened 
fibres, which penetrate the soil and probably serve chiefly as. 
holdfasts. The germination of the minute seeds of 0. ramosa 
(fig. 7) has been investigated by Vaucher and Caspary. This 
occurs in the soil, but an adherence to the extremity of a 
young rootlet of the hemp is almost immediately effected. At 
first the little parasite puts out a number of rootlets (fig. 8), 
but before long it forms a true union with the stock. The- 
vessels of the hemp are stated to pass actually into the young^ 
Orobanche^ as represented in fig. 9, and in the adult state in 
fig. 6. Besides Lathrcea and Orobanche, there are about twenty 
other genera in the order Orobcmchacece, containing over 130 
species, the whole of which are parasitic. 
The leafy or chlorophyllous parasites may perhaps form tlie- 
subject of another communication. 
