SOME MINOR GENERA 315 
North Africa, and Western Asia, one British. Several of them are of 
stately habit, whilst others are dwarfs. Of the former, two or three are 
occasionally grown where there is plenty of room to show them off. Our 
native Onopordon Acanthiwm is one of the best.. Its branched woolly 
stem is 4 or 5 feet high, and the oblong spiny leaves are covered on both 
sides with white woolly hairs. The flower-heads are about 2 inches 
across, contracted at the mouth and very cobwebby ; the flowers pale 
purple; July to September. This is a perennial. A larger species (of 
biennial duration) is 0. arabicum, which reaches a height of 8 feet, with 
woolly leaves and stem, and purple heads. It is a native of South 
Europe, and was introduced in 1686. Another fine biennial from South 
Europe, introduced 1640, is O. illyricwm, of similar appearance to 0. 
Acanthium, but with stiffer, more branching stem (6 feet high), and more 
deeply cut and spiny leaves, flowering in July. These plants succeed in 
almost any garden soil, and may be effectively grown in the rougher, 
drier parts of a garden, on the edge of a plantation or shrubbery, or to 
form bold clumps near a lawn. Seeds should be sown in pots in spring, 
and planted out later. 
Sitysum (Greek, sillybon, the name for a white-spotted Thistle). 
Milk Thistle. A genus consisting of one species, Silybum Marianum, 
the Blessed, Holy, or Our Lady’s Milk Thistle, a South European plant, 
long naturalised in this country. The stems are not winged like those of 
Silybum, but grooved, and varying from 1 to 4 feet inheight. The leaves 
are large with stout spines, and white nerves. The globose, purple heads 
are from 1 to 2 inches across, the bracts broad, leathery and spiny ; July 
to September. The white veins of the leaves gave rise to the legend— 
preserved in the name Marianwm—that a drop of the Virgin Mary’s 
milk fell upon this plant and stained it. Its presence as a wild plant in 
Britain is accounted for by the fact that it was formerly cultivated for 
culinary purposes, the roots and stems being boiled and eaten, the head 
treated as an Artichoke, and the leaves used in spring salads. Any 
garden soil will suit it, and it may be grown as recommended for 
Onopordon. 
GRINDELIA (named in honour of David H. Grindel, German botanist, 
1766-1836). A genus of about twenty species of shrubby and herbaceous 
perennials and biennials, natives of North and South America. They 
have alternate, stalkless or somewhat stem-clasping leaves, and large 
yellow flower-heads, borne solitarily at the ends of the branches, an 
inch to 2 inches across. Several species are suitable for garden purposes, 
though they do not appear to be widely known. Grindelia glutinosa is 
