[Illustration: FLOWER OF HELIANTHUS ARGOPHYLLUS.]
The genus Helianthus is almost entirely North-American, and for the
distinction and limitation of its species we are indebted to the labor of
Dr. Asa Gray, now universally recognized as the highest authority on North
American plants. In the recently published second part of his "Synoptical
Flora of North America" he has described thirty-nine species, six of which
are annual. The synonyms and cross-naming adopted by previous authors have
led to much confusion, which probably will not now be altogether cleared
up, for Dr. Gray warns us that the characters of some of the species are
variable, especially in cultivation. It may be added that some at least of
the species readily form hybrids. There is always more or less difficulty
with a variable genus in making garden plants fit wild specific types, but
in the following notes I have described no kinds which I have not myself
cultivated, selecting the best forms and giving them the names assigned
severally by Dr. Gray to the species to which our garden plants seem to
come nearest.
[Illustration: HELIANTHUS ARGOPHYLLUS, SHOWING HABIT OF GROWTH.]
_Helianthus multiflorus_, or, according to Asa Gray, speaking botanically,
H. decapetalus hort. var. multiflorus, is mentioned first, because it is
the subject of the colored illustration. The name multiflorus is
established by long usage, and perhaps was originally given in contrast to
the few-flowered habit of H. annuus, for the type of the species is more
floriferous than the variety of which Asa Gray says that it is "known only
in cultivation from early times, must have been derived from
decapetalus," a statement which gardeners would hardly have accepted on
less indisputable authority, as they will all think the habit and
appearance of the two plants widely different. The variety multiflorus has
several forms; the commonest form is double, the disk being filled with
ligules much shorter than those of the ray flowers, after the form of many
daisy-like composites. In this double form the day flowers are often
wanting. It is common also on old plants in poor soils to see double and
single flowers from the same root. In the single forms the size of the
flowers varies, the difference being due to cultivation as often as to
kind. I have obtained by far the finest flowers by the following
treatment: In early spring, when the young shoots are about an inch high,
cut some off, each with a portion of young root, and plant them singly in
deep rich soil, and a sheltered but not shaded situation. By August each
will have made a large bush, branching out from one stalk at the base,
with from thirty to forty flowers open at a time, each 5 inches across.
The same plants if well dressed produce good flowers the second season,
but after that the stalks become crowded, and the flowers degenerate. The
same treatment suits most of the perennial sunflowers. The following kinds
are mentioned in the order in which they occur in Asa Gray's book:
[Illustration: HELIANTHUS MULTIFLORUS, SHOWING HABIT OF GROWTH.]