Diánthus. Some of the species of this genus are the most prominent of the Flower-garden, not only for their beauty, but also their fragrance, which is peculiarly grateful, especially in the well known and celebrated pink and carnation, with the Sweet-william, which was esteemed, in the days of old, "for its beauty to deck up the bosoms of the beautiful, and garlands and crowns for pleasure." The finest species are D. barbàtus, and D. barbàtus plèno, Sweet-william; D. discolor D. chinènsis; D. alpínus, D. supérbus; D. caryophyllus, from which have originated the Picotee and the Carnation; D. plumàrius, from which originated the Double Pink; D. fràgrans and D. supérbus. Several of these, although they will stand the severest cold, have to be protected in frames during winter, to have them in the perfection of beauty. For the character of a Pink and Carnation, see May.
Dictámnus. Two species of this genus, D. fraxinélla and D. álbus, have been cultivated and esteemed upwards of two hundred and forty years. A plant of the first of these species, when gently rubbed, emits an odour like that of lemon-peel; and when bruised emits a balsamic scent, which is strongest in the pedicles of the flowers. They have glands of a rusty colour, that exude a viscid juice, or resin, which exhales in vapour, and in a dark place may be seen to take fire. Its flowers are red, those of the other white, in loose terminale spikes; the flower has five petals, clawed and unequal, with glandular dots; in bloom from May to July; delights in sandy loam.
Dodecàtheon. This is a native genus, and commonly called American cowslip. The generic term, a name of the Romans, signifying twelve gods or divinities, is applied with great absurdity to a plant, a native of a world the Romans never saw nor had any idea of, neither resembling, in any particular, the poetical fancy of their writers. The most admired species is D. mèdia; the flowers are in umbels, on a pedicle, from six to twelve inches high; the corolla is rotata reflexa, colour light purple, bottom of petals lake and yellow; blooming in May. The white variety is very much esteemed, and surpasses the preceding. The ground is pure white, the bottom of the petals the same as the other. There is also a spotted variety found on the banks of the Missouri. They delight in brown loam, a half shady situation, inclining to moisture. The foliage soon decays after flowering.
Digitàlis, Fox-glove, about forty species of annuals and herbaceous plants. A few are cultivated in the flower borders, and are very showy. These are D. leucophæa, D. ferrugínea, D. ochroleùca, large yellow; and D. purpuráscens; and are good species. D. purpúrea and D. álba, are very conspicuous biennials; the flowers are solitary, and in long spikes; the corolla of D. purpúrea is campanulate, ventricose, and ringent; the interior is spotted, and is considered the finest of the genus. Delights in poor soil, with a little shade.
Eupatóriums. These generally are native plants, not worthy of notice here, except for two species. E. cœlestínum has syngenesious flowers in flattened panicles, colour fine light blue, blooming from September to November, desirable for its beauty at that season. E. aromàticum may be cultivated for its spicy odour; flowers white, in loose terminale panicles; blooming from August to October. Either of them will grow in common soil.
Gentiánas, a genus of very showy plants, and flower in great abundance. The flowers are tubular and inflated; colour generally blue. A few species are yellow, and some white; flowers in whorls, terminale, or solitary. They grow best in a light rich soil. G. lútea, G. purpúrea, G. septémfida. G. acaúlis is a pretty dwarf growing species, and often used as edgings in flower compartments; the flower dark and light blue; interior of the corolla spotted; has a succession of flower from April to June. We have no doubt of it succeeding in our gardens, but not being plentiful, it has not been perfectly tried. A few years will exhibit it in abundance. G. imbricàta and G. conférta. They are all fine exotics, but many of them may give place to our native species, such as G. Catesbæí; G. ochroleúca; G. incarnàta; with several others, and G. crinàta, which is a biennial, and finely fringed; colour light blue.
Gèum. There are only two species that are worth cultivation, viz. G. quéllyon, once G. coccíneum; and G. hybridum. G. urbànum is sometimes cultivated for its roots, which, when chewed, sweeten the breath. They are all of easy culture. G. quéllyon flowers from May to October, and is a very desirable small plant for the borders, and much esteemed in Europe.
Hemerocállis, Day Lily; two species, H. fúlva and H. gramínea, flower well, and are remarkable among the border flowers for their large yellow or copper coloured corollas, some of them about six inches diameter; bloom from May to July, and will grow in almost any soil. There is a plant known in our gardens as H. cærùlea, which is Fúnkia cærùlea, and has a campanulate corolla, with a cylindrical tube; flowers in spikes; leaves ovate, accuminate.
Hibíscus. There are several herbaceous species very showy and handsome, H. palústris; H. ròseus; H. militàris; H. speciòsus; H. grandiflòrus; and H. púngens. They grow best in moist situations, and where these are not to be had, give them plenty of water, and plant in sandy soil enriched with decayed leaves. The flowers are about six inches in diameter, flowering up the stem, either solitary or in small bunches. H. speciòsus is the most splendid, and deserves a situation in every garden. The roots in winter ought to be covered by litter, tan, or saw dust; but a better method is to lift them, and put them in the cellar, covered with dry earth, and kept from the frost. All the above mentioned species are improved by being protected during winter.
Iris, Flower-de-luce, has many fine species of various shades and colours, I. subiflòra, I. nepalénsis, I. Pallàsii, I. pállida, I. cristàta, I. arenària, I. furcàta, I. germánica, I. florentìna, I. vérna, and I. susiàna. The last is the finest of the herbaceous species; the flowers are striped, blue, brown, and spotted; but we are not certain if it will stand the severity of our winters. The roots of I. florentìna is the orrice root of the druggists. They are all of easy culture in any loamy soil inclining to moisture. The bulbous species will be treated of in September or October. Corolla six-petaled, three erect, and three reclined alternately; proceeding from spathes or sheaths with flowers in succession.