162 ALPINE PLANTS 
the zinc should be bent in a hoop with the ends just 
meeting, and that the lower edge must touch soil all round. 
His theory was that observance of these two points 
ensured the setting up of a galvanic or electrical current 
which prevents slugs crawling over the zinc. I am not 
prepared to vouch for the validity of that claim, but when 
putting down the zinc fence it is easy to be exact in these 
two details, and whatever the real reason I can certainly 
say I have found this little appliance quite an effective 
safeguard against slugs. 
OMPHALODES NITIDA is another choice kind that should 
also be included in the choicest collections either for the 
rockery or the alpine house. The flowers are sky blue, 
borne in spikes of good length. Cuttings of young growth 
may be rooted, but require closely watching in regard 
to watering. 
OnosMA.—Ranking among the choicest of alpine plants, 
Onosma echioides, or, as it is perhaps more frequently 
called, Onosma tauricum, is an altogether lovely plant. 
Its inflated bell-shaped flowers, borne in clusters on arching 
stems, are of a rich yellow, “Golden Drop” being an 
appropriate common name for the plant. It is hardy, 
despite the fact that it is not invariably a success, but 
failure will generally be traceable to the choice of a posi- 
tion where moisture and shelter combine to produce a 
soft, sappy growth. The Onosmas must have a _ thor- 
oughly well-drained soil, and a fully-exposed position 
where sun and wind will ripen every stem before winter 
sets in. There are several species besides O. echioides, 
O. albo-roseum being one that is of very easy culture. 
