| Gard. & For. 10: 95. 10 Mar. 1897; Iris Hartwegii, Baker.FREQUENT inquiries about this pretty Iris show that it is a favorite, and lead me to put on record what I know about the species.Iris Hartwegii occurs in California at elevations of from 1,300 to 4,500 feet, in a belt almost exactly coinciding with that occupied by Pinus Lambertiana. Like this Pine, it does far better on cool, protected northerly slopes than on shallow-soiled hot slopes facing south. The fact that its large clumps die out if the surrounding Pines and shrubs are cleared off, proves that this Iris prefers the shelter, and it does well even when the needles from the Pines smother almost everything else on the ground. The tufts may be small or as much as twenty-four inches in diameter. I have seen whole slopes covered with them. The tender India-yellow color fades in the hot sun very rapidly, but a field of these flags, lit up by the rays of the sun falling through the stand of Pines, is a beautiful sight. The stems range from twelve to eighteen inches at the lowest limit of the plants, to but six or eight inches at its highest range. The size of the flowers varies but slightly, though the falls and standards are somewhat reduced in the highest altitudes. The climatic conditions under which it grows are naturally varied when so wide a range suits this species. The lowest temperature at the height where it begins to appear was 22 degrees, Fahrenheit, in eight years of observation, the highest 112 degrees. Although the seeds from which most trees of the Sugar Pine (Pinus Lambertiana) are raised have been gathered at altitudes between 3,000 and 4,000 feet, it must not be expected that Iris gathered from low limits would do equally well in eastern gardens. The dwarfed plants at 4,500 feet altitude are exposed to very severe winters, tempered only by the heavy snows which fall in those regions. At Panther Creek, Amador County, I have known snowfalls ten feet in depth, while one winter in about five may not know snow deeper than ten inches. Good drainage seems essential to the growth of this Iris, and, above all, a period of rest during the whole summer. In our Sierras, at the altitude of 1,300 feet, no rain falls after the middle of May, unless there happens to be a shower about the Fourth of July, until in fall when the advance showers of winter set in about the middle of September. The mean rainfall at 1,300 feet elevation is about thirty-five inches, most of which falls during December, January and February.Applying these observations to eastern conditions, I would say Iris Hartwegii should have the most sunny place in the garden, unless your summer equals the extreme heat I have recorded. It should be well up on a slope, above a rock wall, or in a similar position, and kept from freezing too deep in the ground. While there are far more gorgeous Irises to be found, and most of them are more easy of cultivation, it is the charm of succeeding with what seems refractory which will add greatly to the pleasure of cultivating Iris Hartwegii. _ TT Berkeley, Calif. George Hansen
| Dykes, The Genus Iris tab. 10, 40. 1913, Rootstock , a slender, hard, wiry, short creeping rhizome. Leaves , linear, somewhat thick and firm, yellowish green, finely veined, 8-12 in. long by ¼ to ¼ in. broad. Stem , slender, wiry, 6-10 in. to the base of the spathes, usually bearing a sheathing leaf. Spathe valves , firm, green, keeled, lanceolate, 1½-4 in. long, one valve being often set an inch or more below the other on the stem ; usually 2-flowered. Pedicel , 1-3 in. long. Ovary , 6-ribbed, almost cylindrical. Tube , very short, of a yellowish green colour. Falls , obovate cuneate, emarginate, narrowing abruptly at the base, of a pale creamy yellow colour with a raised yellow central ridge and veins of a deeper tone. Round the end of the central ridge the surface of the blade is covered with minute papillae, scarcely visible to the naked eye. Standards , oblanceolate cuneate, slightly longer than the falls, of a creamy pale yellow, veined with a deeper shade. Styles , of a pale straw colour. Crests , quadrate, overlapping. Stigma , a triangular tongue. Filaments , pale yellow, ciliate. Anthers , creamy, reaching the stigma. Pollen , creamy. Capsule , about an inch long, nearly cylindrical, but slightly 6-ribbed. Seeds , cubical or nearly so, with coarsely wrinkled yellowish brown coats, the latter being firmly attached to the seeds proper, not loose as in I. spuria.Observations.When this iris was first discovered by Hartweg in 1848 in the mountains of Sacramento in California, it was recognised as coming very near to I. tenax Dougl. It was not until Baker worked at the genus that it was separated as a distinct species. Even then no clear distinction was drawn between the two. In fact, the differentiae are hard to find. The most obvious difference lies in the colour of the flowers, which in I. Hartwegii are always of a pale straw colour, and yet, though seedlings have shown no variation, no great importance can be attached to mere colour as a specific character. Moreover, I. Hartwegii agrees with I. tenax in one remarkable characteristic, namely in the arrangement of the inflorescence, which is of a type not often found in other species. In both, when two flowers are present, the lower spathe valve is set some distance below the other outer valve and the pedicel of the first flower is very short, while that of the second, which emerges from between the two inner valves, is much longer ( see Plate IX).On the whole, we are perhaps almost justified in regarding I. tenax and I. Hartwegii as subspecies or as local forms of one species, especially as such specimens as Davidson's from the San Bernardino Mountains (W) have purple flowers and are therefore indistinguishable from I. tenax, at any rate as herbarium specimens.I. Hartwegii is not common in cultivation in this country, partly because it can rarely be transplanted with success except when growth is active in spring or early summer and partly, no doubt, because it is at best a weak-growing and rather insignificant species. It is best propagated from seeds, which germinate freely and which should be sown where the plants are to remain. In its native home in California it grows in very loose soil, either red volcanic debris or granitic sand, in dry pine woods, where it seldom gets really wet. We must not, however, infer from this fact that it will prosper in the shade in England, for the dankness of shady places in our gardens must be very different from the shade of pine trees under the hot Californian sun. Experience of its cultivation has shown that it does well in light sandy non-calcareous soil in a sunny, well-drained position. The plants that I have had in cultivation were raised from seeds, which I owed to the kindness of Mr Carl Purdy.N. B. Since the above was written I have received a letter from Mr S. B. . Parish containing a description of his I. Hartwegii var. australis. This is the plant which Foster was inclined to name I. Parishii, without, however, ever proceeding to the actual publication of the name. Unfortunately Mr Parish does not say how his plant, which grows in open coniferous forests at an elevation of from 5000-6000 feet, is to be distinguished either from I. Hartwegii or from I. tenax.The colour of the flowers is light blue with darker veins and I take the expression "bracts distant" to mean that the spathe valves are set at some distance apart on the stem,-a feature that has already been mentioned as characteristic of both I. Hartwegii and I. tenax. On the whole, I am inclined to think that there is no specific difference between I. Hartwegii and I. tenax, but that this is only one more instance of a Californian species, which varies in colour in different localities. I hope shortly to obtain seeds of the San Bernardino plant and thus to be able to compare it with I. tenax from Oregon and Washington.