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■ (SPEC) Iris dichotoma Pallas

1773, botanical author Pallas

Iris dichotoma Pallas (aka Pardanthopsis dichotoma(Pallas) Lenz). (Peter Pallas, 1773, N. China); Pard-S1M; Inch diameter flowers of blue, rarely white, cream-yellow, or pink, lasting only one day but on multi-branched stems with sometimes hundreds of flowers See below:

dichotoma- 4flowers Christy HenslerChristy Hensler photoChristy Hensler photodichotoma 600Christy Hensler photoBiodiversity Heritage LibraryChristy Hensler photoDichotoma in bulletin 1934Pries photoChristy Hensler photoChristy Hensler photoI. dicotoma: yellow variationI. dicotomaChristy Hensler photoChristy Hensler photoChristy Hensler photoChristy Hensler photoFrom Dykes The Genus IrisPhoto by Joe Pye WeedPhoto by Joe Pye WeedI. dicotoma: pink variation


Reise 3: 712. tab. a, fig. 2. 1773;
Dickson 1794;
Flora Of China 35. Iris dichotoma Pallas, Reise Russ. Reich. 3: 712. 1776.
野鸢尾 ye yuan wei
Pardanthopsis dichotoma (Pallas) Lenz.
Rhizomes erect, brown, very short, stout. Roots long, thick. Leaves in basal fans and alternate on flowering stems proximally, grayish green, sword-shaped, slightly curved, 15--35 × 1.5--3 cm, midvein absent. Flowering stems dichotomously branched, 40--60 cm, leafy; spathes 4 or 5, green, lanceolate, 1.5--2.3 cm, 3- or 4-flowered, apex obtuse. Flowers violet, pale blue, or cream with purplish brown markings, 4--4.5 cm in diam., spiralling after anthesis; pedicel exserted from spathes, 2--3.5 cm, stiff, persistent. Perianth tube extremely short; outer segments broadly oblanceolate, 3--3.5 × ca. 1 cm, claw striped with yellowish brown, limb with darker spots on a central, pale patch; inner segments narrowly obovate, ca. 2.5 cm × 6--8 mm, apex retuse. Stamens 1.6--1.8 cm. Ovary green, ca. 1 cm. Style branches flat, ca. 2.5 cm. Capsule yellowish green, cylindric, 3.5--5 × 1--1.2 cm. Seeds dark brown, elliptic, with small wings. Fl. Jul--Aug, fr. Aug--Sep. 2 n = 32*.
Quercus forests, sandy grasslands, dry sunny areas; 200--2300 m. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Yunnan [Korea, Mongolia, Russia].
This species was treated by Goldblatt et al. (in Kubitzki, Fam. Gen. Vasc. Pl. 3: 326. 1998) under Pardanthopsis (Hance) Lenz, a monospecific genus between Iris and Belamcanda.
Botanical Register, volume 3, 1816 "The rarest species of its genus in our collections, and marked by more than one striking anomaly. Its foliage and stem partake considerably of the habit of those in Pardanthus chinensis, or China-Ixia, though they differ in verdure; the stem is proportionally the slenderest in the genus; the flower the smallest, never expand until after mid-day, and collapse before night by a twofold inflexion, rolling inwards at the limb or upper portion, and twisting spirally together at the ungues or lower. The laminae of the inner segments are two-lobed, and the lobes of the outer lip of the stigmas villous at the upper surface. We did not perceive pubescence of any kind on the ungues of the outer segments, though these are said by Pallas to exhibit a few fine scarcely perceptible villi.
Native of Dauria, where it is called Cheitschi (Scissors) in the Mogol dialect, from the form of the fork produced by the two branches; the lower of which however is not always elongated to the length of the other, and then the appellation does not apply. Stated to have been introduced by Mr. John Bell in 1784, but we suspect that the plant from which the drawing was made is only one now in this country. This had been raised from seed received under the name of Iris pomeridiana, by Messrs. Whitley and Co. of the Fulham nursery, where it flowered in August Last; and was found to do very well in the open ground on a warm sheltered border.
Rootstock horizontal. Leaves about 7, equitant, clasping the lower part of the stem, lanceolate, 6 inches or more in length, scarcely one broad. Stem 1 ½ to 2 feet high or higher, round, slender, generally dichotomous; branches long and generally equal, leafless, simple, with a small leaf at their base. Flowers with long peduncles, of a violet-purplish colour, scentless, of short duration. Corolla six-parted to the base, entirely or nearly beardless, 1 inch and ¼ deep; segments cuneately oblong; ungues from upright, spreading; the laminae of the 3 outer nearly twice shorter than the white and purple figured ungues; 3 inner but little longer than the ungues of the outer ones, with a very short lamina divided into two lobes with intermediate teeth. The lobes of the inner lip of the stigmas lanceolate contiguous at the inner edges and rolled back at the outer; the outer lip bifid, lobes villous on the inside."
JACQUES, Nouvelles, Iris Dichotome, Annales de Flore et De Pomone, 1838, pp. 63-64.
Curtis's Botanical Magazine 105: tab. 6428. 1879, This is a very distinct species of Iris, remarkable for its much branched habit, short spathes and fugacious, rather small bright purple flowers, which expand in the evening, one after another in the same cluster on successive days, after the fashion of Tigridia or Pardanthus. It is a native of the Eastern half of Siberia, and has long been known in cultivation, but it has always been very rare, and it has not yet appeared in the Botanical Magazine. The drawing was made from a plant that flowered at Kew last September, raised, I believe, originally from seeds sent by Dr. Hance.
>Descr. Rhizome short-creeping, with the tufts of leaves crowded upon it. Produced leaves six or eight in a distichous tuft, the base of which exfends over the lowest half-foot of the stem, ensiform, pale green, the largest about a foot long and an inch broad. Flowering-stems three or four feet high, much more branched than in any other species of the genus. Flowers four or six in a cluster, scentless, bright violet-purple. Spathe-valves under an inch long, subequal, the outer ones oblong green and firm in texture, the inner membranous. Pedicels just as long as the spathe, articulated at the tip. Ovary clavate, half an inch long; perianth-tube obsolete above the ovary; outer segments of the limb oblanceolate-spathulate, an inch and a half long, the reflexing roundish violet-purple limb not more than half as long as the permanently suberect claw, which has a beardless pale green keel, from which lines of bright purple on a paler ground radiate transversely; inner segments of the perianth similar in shape to the outer, but rather shorter, plain purple, deeply emarginate at the tip. Petaloid branches of the style oblanceoiate — oblong, nearly white; crests lanceolate, very acute. Anthers linear-oblong, equalling in length the free filaments. — J. G. B.
Robert Sweet in The British Flower Garden vol. 1, 1st., Series, table 96, (1823-25),
Dykes, The Genus Iris 1914;
This curious Iris was first discovered by Pallas and since that time it has been introduced and reintroduced into cultivation at intervals. It has often been confused with Pardanthus (Belamcanda) chinensis and the growth of the two plants is certainly very similar. The flowers, however, are very different, for the segments of those of the Pardanthus are all approximately equal while the standards of I . dichotoma are noticeably smaller than the falls. The seeds too are very different, those of the Pardanthus being relatively large and spherical, with glossy black iridescent coats, and thus easily distinguished from those of I. dichotoma (see Plate XLVIII, Fig. II}. This Iris probably produces more flowers on each stem than any other Iris. The stem is much branched and even the branches often issue in pairs at the same point. Moreover from each spathe as many as five or even more flowers are produced in succession. Each flower, unfortunately, lasts only a few hours and often only opens in the afternoon-a character which gained for the plant the synonym of I. vespertina. However, such is the profusion of flowers that there are usually four or six to be found open at once on each plant.
Another peculiarity of this Iris lies in the fact that it does not begin to bloom until about the middle of August and then continues in flower for about three weeks or a month. Each flower as it dies twists up in a curious spiral and often falls off together with the ovary between which and the pedicel there is an articulation. In all the other known Irises, if the withered flower falls very easily, it always snaps off above the ovary, except perhaps in the case of I. japonica.
Iris dichotoma appears to be variable in colour (cf. Franchet, Pl. David. I. p. 298), although at present only a dull greenish white form mottled with brown purple, seems to be in cultivation. The Botanical Magazine figure represents a purple flowered form, and Foster had in flower in August 1905 a similar plant that he raised from seeds sent from Mukden, which he described as having falls of a reddish lurid purple with a dead white signal patch and standards of a somewhat faint red purple.
It is not a difficult Iris to cultivate especially if it is raised from seed. The young growths suffer occasionally from late frosts in spring but in a warm sheltered corner it does well and seedling plants will flower in little more than a year from the time of germination. Seed is unfortunately not very readily obtained in England even with artificial pollination. In Southern Europe, however, seed is set readily.
I. dichotoma does not appear to be exacting as to soil but the individual plant is probably short-lived, and so much of its energy seems to go into the flowering stem that no lateral shoots are formed, with the result that the whole plant not infrequently dies after flowering. With all its defects, however, I. dichotoma is not to be despised, for it provides us with Iris flowers at a season when few other species can be depended upon to bloom.
1922-1923 Plant Introductions; OFFICE OF FOREIGN SEED AND PLANT INTRODUCTION, BUREAU OF PLANT INDUSTRY, UNITED STATES DEPARTMENT OF AGRICULTURE, "49907. IRIS DICHOTOMA. Iris. From China. Seeds presented by N. H. Cowdry. This attractive small iris is distinct from those commonly grown for decorative purposes in the continued paired branching of its flower stalk, its late flowering, and in the fact that it opens its attractive purple flowers only in the afternoon, The species should prove of especial interest to iris fanciers."
Bulletin of the American Iris Society, vol 52, p.77, 1934; illustrated
Iris dichotoma Pallas
Many years have elapsed since the first flowering of the Vesper Iris in my garden but only this season have.I managed to get flowers. to the photographer for its portrait. The first seeds carne to me from Peiping, sent by a Chinese doctor who accompanied me on a visit to the Western tombs and who seemed somewhat amused by my eagerness over this slender plant that bloomed in the grassy meadows thereabouts. The plants from that seed gave only the familiar creamy white flowers variously dotted and blotched with dull lavender, except in one case which was pure white with yellow hafts and no darker reticulations..
Since then other seed has produced the lavender form illustrated but no particular mention has been made of the fact that this lavender varies somewhat in hue and the falls vary somewhat in the amount of their markings. Sometime perhaps we shall have selected strains of this iris to add interest to the summer borders. Notes have already been given in the BULLETIN as to its usefulness in various parts of the country and possibly all members know that it occupies a separate division among all irises. The roots are thick and fleshy, springing from an irregular somewhat knotty crown that sends up each year a strong stalk, with wide leaves arranged somewhat like those of the blackberry lily (Belemcanda chinensis) and ending in a widely branching stalk. Each tip carries a sheath from which many flowers are produced. The flowers, natural size in our picture, are not large and open only in the afternoon, here usually about two-thirty, and close after sundown. Whether or not it is common elsewhere, it has been noticed that here they are visited by wasps as well as bees and flies. Thanks to these many insect visitors, the flowering is usually followed by a good crop of seed. This, if planted early will produce small plants flowering late the first autumn, but the best effects come the second and following years.
Iris dichotoma
Plants were set as young seedlings, in a semi-stiff micaceous loam, in Fairfax County, Va., in back of low growing foundation planting of shrubs, having a southeastern exposure. Well drained. They lived and increased in size of plant· and beauty of flower each season for three perhaps four years, and then suddenly passed away. Their passing however occurred in the terrible drouth year of 1930 when water in the suburbs was at a premium and could not be used for the garden. The cooling effect of the surrounding shrubs seemed to be an aid in their well 'being until that drouth year. As they developed in leafage, so they increased in beauty of flower, the plants a veritable fountain of bloom. The mature heads of bloom showed so many buds, that though each flower lasts less than a day, each day for nearly a week, the fountain endured and 'was showy enough to attract attention of visitors.
Forms of dichotorna
Iris dichotoma, native of Eastern Asia, is a decidedly interesting Iris species. It blooms at a time when most Iris are long through, season generally August and early September. The flowers are born on stems in surprising numbers. Individual bloom lasts but a day. Its habit of flowering in the afternoon explains the application of the name Vesper Iris, which it truly is. Because of its novel features, I decided to experiment with seedlings and watch for variants in colorings. This year, out of several hundred seedlings of a cross of a form from Manchuria with a form from China, I obtained three rather marked variations from the common coloring. The type I have in abundance.
is a lavender self. In these new seedlings I found a very pale form, practically a self white. Another marked form was a very intensely colored type. Two specimens of this -coloring occurred. And thirdly, a form with a snow-white signal patch (that area where the beard is on the bearded iris) with ordinary coloring. Many seedlings had a slight marking of white but this form was very noticeable because of its extra large size rendering it notable at once.
I have selfed these three forms and have seed pods on them practically ripe. It will be highly interesting to see just what they yield. Perhaps color and size improvements. will bring this iris into more gardens. The study of wildlings and exotics is an engaging pastime. Perhaps others have had some experiences with this iris that would be interesting to readers.
Perry 1938; Tingle 1938; Starker 1938;
Waddick & Zhao, Iris of China, 1992, illustrated in color.


Iris Dichotome; Vesper Iris; Afternoon Iris; Iris dichotoma; Evansia dichotoma; and Vespertina, descaisne; Pardanthus dicotomus, Ledeb.; Iris pomeridiana, Fischer, ex Ledeb.

Chromosome counts

2n=32, Doronkin & Krasnikov, 1984; 2n=32, Sha et al., 1995; 2n=32, Yan et al., 1995 Doronkin, V. M. & A. A. Krasnikov. 1984. Cytotaxonomic studies in some Siberian species of the genus Iris (Iridaceae). Bot. Zhurn. SSSR 65(5): 683–685. (In Russian). Sha, W., L. h. Wang, X. j. Yang, X. l. Qi, G. h. Ma & D. y. Zhao. 1995. Chromosome numbers of 20 species from northeast China. J. Wuhan Bot. Res. 32(2): 180–182. Yan, G. x., S. z. Zheng, F. h. Xue, J. f. Yun, L. y. Wang & X. q. Fu. 1995. The chromosome numbers of 35 forage species and their geographical distribution. Grassl. China 1995(1): 16–20.


Iris dichotoma cultivars: 'Dichotoma Alba', 'Shilka'.
4 flowers of unnamed variations of Iris dichotoma


Iris dichotoma crosses: 'Ai Hua', 'Aurural Sail., 'Azure Pinwheel, 'Blazing Sunflower', Bountiful Blush', 'Bright Smile'. 'Butterfly Magic', 'Candy Lilies', 'Cherry Pie', 'Chic Leopard', 'Chocolate Knight', 'Colorful Stellfroid', 'Dancing Woman', 'Daybreak Sail' 'Dazzler Series', 'Fiery Rhapsody, 'Fire Leaf', 'Happy Yan Yan', 'Heart Of Darkness', 'Jungle Colors', 'Kiba Giants' 'Laced Lavender', 'Lost Bar', 'Mandarin Lady', 'Norrisii', 'Moonlit Hairpin', 'Orange Diamond', 'Pastel Parfait', 'Pink Leopard', 'Romantic Celebration', 'Rosy Brocade', 'Sangria', 'Seiya Hui', 'Sharp Shine', 'Sheng Ni', 'Shining Butterfly', 'Slight Smile', 'Sparkling Fire', 'Star Eyes','Spooky World', 'Spotted Dog Hui', 'Starlit Shell', 'Starry Bodhi', 'Summer Candy', 'Summer Snow', 'Sunset Tones'. 'Sweet Princess', 'Wedding Dress',

Distribution and Cultivation

Distribution: Region---

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Dichotoma_in_bulletin_1934.jpgjpg Dichotoma_in_bulletin_1934.jpg manage 62 K 12 Jul 2016 - 16:40 BobPries  
Dykes_plate_XLVIII_dichotoma.jpgjpg Dykes_plate_XLVIII_dichotoma.jpg manage 49 K 04 Jan 2011 - 15:56 BobPries From Dykes The Genus Iris
dichotoma-_4flowers_Christy_Hensler.jpgjpg dichotoma-_4flowers_Christy_Hensler.jpg manage 59 K 23 Dec 2014 - 20:19 BobPries  
dichotoma-flowers_Christy_Hensler.jpgjpg dichotoma-flowers_Christy_Hensler.jpg manage 35 K 24 Dec 2014 - 13:09 BobPries Christy Hensler photo
dichotoma-pink_hensler.jpgjpg dichotoma-pink_hensler.jpg manage 93 K 24 Dec 2014 - 12:57 BobPries Christy Hensler photo
dichotoma_600.jpgjpg dichotoma_600.jpg manage 36 K 29 Sep 2010 - 16:04 BobPries  
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dichotoma_seed_pries.jpgjpg dichotoma_seed_pries.jpg manage 227 K 24 Dec 2014 - 12:54 BobPries Pries photo
dichotoma_white_Hensler.jpgjpg dichotoma_white_Hensler.jpg manage 27 K 24 Dec 2014 - 12:56 BobPries Christy Hensler photo
dichotoma_yellow__hensler2.jpgjpg dichotoma_yellow__hensler2.jpg manage 37 K 24 Dec 2014 - 12:58 BobPries Christy Hensler photo
dico_ylo.jpgjpg dico_ylo.jpg manage 29 K 16 Jan 2010 - 19:35 Main.shanatse I. dicotoma: yellow variation
dicotoma.jpgjpg dicotoma.jpg manage 33 K 16 Jan 2010 - 19:33 Main.shanatse I. dicotoma
dicotoma_pods_hensler.jpgjpg dicotoma_pods_hensler.jpg manage 211 K 24 Dec 2014 - 13:01 BobPries Christy Hensler photo
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idico01.JPGJPG idico01.JPG manage 70 K 23 Oct 2014 - 16:00 TerryLaurin Photo by Joe Pye Weed's Garden
idico02.JPGJPG idico02.JPG manage 92 K 23 Oct 2014 - 16:02 TerryLaurin Photo by Joe Pye Weed's Garden
rose-dico.jpgjpg rose-dico.jpg manage 29 K 16 Jan 2010 - 19:35 Main.shanatse I. dicotoma: pink variation
Topic revision: r29 - 23 Aug 2021, BobPries
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