■ (SPEC) Iris decora Wall.

1825, botanical author Wallich

Iris decora Wall. (Nathanael Wallich, botanical author). As Iris nepalensis D. Don in 1939 Checklist. (D. Don, 1825, W. Central Himalayas to Yunnan); Subgenus Nepalensis. Height 4-12" (10-30 cm); Flowers pale bluish lavender to deep reddish purple and whitish veined with purple on the haft of the falls, bright yellow-orange crest tipped white or purple. See below:
decora.jpgDecora root.jpgdecora seed.jpgDecoraIn Royle.jpgdecorainWallich.jpgIris-decora-2 pods walker.jpgIris-decora-3.jpgIris-decora-5.jpgIris-decora-9.jpgIris decora 3 flowersWalker.jpgIris decora  17-06-09  mini.jpgIrisdecoraKenWalkerSIGNA01.jpgnepalensesis edited-1.jpg
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References:

Iris decora Wall., Pl. Asiat. Rar. 1: 77 (1830).
Prodr. Flora of Nepal 54. 1825;
Flora Of China, 31. Iris decora Wallich, Pl. Asiat. Rar. 1: 77. 1830.

泥泊尔鸢尾 ni bo er yuan wei

Iris nepalensis D. Don; I. yunnanensis H. Léveillé; Junopsis decora (Wallich) W. Schulze.

Plants densely tufted, with small growing point. Roots swollen, fusiform, tuberous. Leaves linear, 10--35(--60) cm × 2--8 mm, veins 2 or 3, base surrounded by brown fibers. Flowering stems sometimes shortly 1-branched, 10--25 cm × 2--3 mm; spathes 3, green, lanceolate, 4.5--9.5 cm, 2-flowered. Flowers violet or pale blue, 2.5--6 cm in diam. Perianth tube 2.5--3 cm; outer segments spreading, obovate, 2.5--4 × 0.8--1.8 cm, crest central, yellow, low, undulate; inner segments erect, narrowly elliptic, 2.5--4 × 0.5--1.2 cm. Stamens 1.5--2.5 cm; anthers yellowish white. Style branches 2--3.5 cm. Capsule ellipsoid to ovoid, 2--3.5 × ca. 1 cm, apex shortly pointed. Fl. Jun, fr. Jul--Aug. 2 n = 24.

Grassy hillsides on plateaus, open stony pastures, cliffs; 2800--3100 m. Sichuan, Xizang, Yunnan [Bhutan, N India, Nepal].

White-flowered forms from Yunnan have been described as Iris decora var. leucantha X. D. Dong & Y. T. Zhao (Bull. Bot. Res., Harbin 18: 150. 1998. Much further work needs to be undertaken on the I. decora group. According to one of us (Noltie), true I. decora is a large plant probably restricted to Bhutan, Nepal, and S Xizang. The plant commonly occurring in China is much smaller and grades into I. collettii.
Royle 1839 ;
Barr 1915; Berry 1929;
Dykes, The Genus Iris, tab. 39.186.1913,

This little known Iris has been the cause of much confusion. In his original description, Don places it under the heading 'Flores barbatae' but makes no further mention of any beard. As a matter of fact there is not really a beard although the much crinkled crest is surmounted here and there by a few thread like processes.

The chief peculiarity of I. nepalensis is to be found in its rootstock, which in the resting state consists of a bundle of fleshy roots, often swollen out towards their extremities and bearing a considerable resemblance to the rootstock of a Hemerocallis (cf. Fig. 25, p. 185). These roots are attached to a small hard disc, surrounded by the fibrous remains of old leaves, from the centre of which the new growths emerge.

The exact relationship of I. Collettii to the typical plant is not yet established, although the evidence that has accumulated tends to weaken its claim to specific rank. Unfortunately I have never yet seen I. Collettii in flower, though I believe that I now possess specimens from Yunnan, which I owe to the kindness of the Abbe Ducloux. The typical I. nepalensis seems to differ from I. Collettii in its taller growth, its glaucous narrow leaves and in the structure of the latter. These in the type bear on one side a single prominent central rib, and on the reverse two similar ribs, one on either side of the centre. In I. Collettio the leaves of the non-flowering tufts are broader and have two ribs on one side and three on the other of the leaves.

Moreover, I. Collettii appears to be far more floriferous. Two or more stem, which are sometimes very short and sometimes 2-3 in. long, rise close together, and the spathes usually produce two andsometimes three or even four flowers.

In cultivation it was Foster's experience that I. Collettii was easier to manage than I. nepalensis, which stands entirely apart from all other Irises in its needs. True to its habits in its native home, I. nepalensis lies dormant for six months during the time when the dry N.E. winds would be blowing and only grows during the period of the heavy rains of the S.W. Monsoon. Thus even in England the leaves die down late in October and do not appear again until April or May. When growth once begins it is rapid, and the plants are usually in flower during the latter part of June or the first half of July. The individual flowers are very short-lived and do not last more than twelve hours unless the weather is very dull and cool. Since this is so, there is less likelihood of pollination being effected by insects, and if it is desired to obtain seeds it is best to pollinate the flowers artificially. Capsules then form readily and seeds are produced in abundance.

The seeds should be sown in the autumn rather thinly in large pots, which may be treated in the same way as pots of other Iris seeds (see p. 235). Germination, however, will not take place until April or May, and care must be taken that the soil is not allowed to become too dry at that time. The young plants should be kept well supplied with water throughout the summer and should be allowed to remain in the pots. When the leaves turn yellow water should be withheld, and the young plants can then be shaken out of the soil and stored in dry sand for the winter. It will be found that each has formed from one to three of the tuberous fleshy roots.

The old plants should also be lifted and stored in dry sand when the leaves wither in autumn, and, together with the seedling plants, they should be planted out in March or April in rich, moist soil. I incline to think that they do better in a position where they are shaded during part of the day than in an entirely open situation.
Fig. 27. Waddick & Zhao, Iris of China, 1992, illustrated in color.

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Synonyms;

Iris fasciculata Jacquemont; Neubeckia decora (Wall.) Klatt, Linnaea 34: 590 (1866). Neubecki decora and sulcatta Klatt; Iris sulcata Wall.; Iris yunnanensis Leveille. Index Kewensis 1230: = nepalensis;
As Iris nepalensis ----

Chromosome number

Don, 2n=34, Roy et al., 1988. ----

Variations

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Hybrids

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Distribution


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-- Main.RPries - 2010-01-09
  • From "The Iris" Brian Mathew.

"Iris decora is a native of the Himalayas over a very wide area from Kashmir in the West through Nepal, Sikkim and Bhutan to the south-west China provinces of Yunnan and Szechuan. To the north it reaches into southern Khasia and Shillong. It is a plant of sunny hills and pastures, mountain scrub, rocky crevices or clearings in rhododendron forest, flowering in May to July at altitudes of 100-4300 meters. -- DavidN - 23 Feb 2010
  • -- DavidN - 23 Feb 2010
  • My plant was grown from seed sent to me by Lesley Cox of Dunedin, New Zealand. It was sown May 2007 and flowered for the first time June 2009. -- DavidN - 23 Feb 2010
Topic attachments
I Attachment Action Size Date Who Comment
DecoraIn_Royle.jpgjpg DecoraIn_Royle.jpg manage 40 K 13 Jul 2016 - 17:56 BobPries courtesy Biodiversity Heritage Library
Decora_root.jpgjpg Decora_root.jpg manage 24 K 30 Sep 2010 - 17:49 UnknownUser  
Iris-decora-2_pods_walker.jpgjpg Iris-decora-2_pods_walker.jpg manage 40 K 15 Jan 2015 - 16:46 BobPries Ken Walker photo
Iris-decora-3.jpgjpg Iris-decora-3.jpg manage 37 K 29 Sep 2010 - 17:15 UnknownUser Decora seeds
Iris-decora-5.jpgjpg Iris-decora-5.jpg manage 26 K 15 Jan 2015 - 16:43 BobPries  
Iris-decora-9.jpgjpg Iris-decora-9.jpg manage 130 K 13 Jul 2016 - 17:54 BobPries Ken Walker photo
Iris_decora_3_flowersWalker.jpgjpg Iris_decora_3_flowersWalker.jpg manage 76 K 13 Jul 2016 - 18:11 BobPries Ken Walker photo
Iris_decora__17-06-09__mini.jpgjpg Iris_decora__17-06-09__mini.jpg manage 22 K 23 Feb 2010 - 20:37 Main.deesen Iris decora
IrisdecoraKenWalkerSIGNA01.jpgjpg IrisdecoraKenWalkerSIGNA01.jpg manage 43 K 11 Oct 2014 - 14:25 Main.TLaurin Photo by Ken Walker-SIGNA
decora.jpgjpg decora.jpg manage 603 K 15 Jan 2015 - 16:44 BobPries  
decora_seed.jpgjpg decora_seed.jpg manage 16 K 15 Jan 2015 - 16:45 BobPries Pries photo
decorainWallich.jpgjpg decorainWallich.jpg manage 72 K 14 Jul 2016 - 12:14 BobPries  
nepalensesis_edited-1.jpgjpg nepalensesis_edited-1.jpg manage 55 K 09 Jan 2010 - 21:43 UnknownUser Dykes Plate
Topic revision: r15 - 15 Dec 2018, BobPries
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