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■ (SPEC) Iris tenuissima

Botanican author Dykes, 1912

Iris tenuissima Dykes (W. R. Dykes1912). Flower color is typically cream or off-white, veined in gold or violet, with narrow floral segments and spreading standards. Usually two flowers per stem, stems to 8-12 inches tall, though many forms are stemless. Style crests are very long and narrow, only slightly reflexed. Very long perianth tube, slightly swollen at tip, with broad spathes, closed. Leaves are narrow, light green, often glaucous, and stained pink or red at base. Evergreen.

Eastwood described light yellow stemless forms as Iris citrina in 1942; Lenz later subsumed this species into Iris tenuissima. Dykes described this species as differing from Iris macrosiphon "by the broader, shorter spathes and comparatively short perianth tube."

I. tenuissima is found in northern California, from around the north end of the Sacramento Valley to the southern part of the Siskiyou Mountains, and eastward on the western slopes of the Cascades, growing in dry, sunny woodland situations.

See below:
Iris tenuissima-1a.jpgIrisTenuissima01.jpgIrisTenuissima02.jpgiristenuissima02.JPGIrisTenuissima03.jpgtenuissima01.JPG


Dykes, Gard. Chron., ser. 3, 51: 18 (1912).
Revue Horticole 84: page 50, February 1, 1912
Flora of North America Editorial Committee (2002). Flora of North America North of Mexico 26: 1-723. Oxford University Press, New York, Oxford.
Revue Horticole 84: page 118, March 1, 1912
Dykes in The Genus Iris, 1913;
Rootstock , a slender rhizome.
Leaves , few in number, linear, acuminate, r 2-14 in. by ¼ in.
Stem , I 2 in., unbranched, bearing 3 or 4 reduced leaves.
Spathes , 2-flowered, with navicular, acuminate, rigid valves, about 2 m. long.
Pedicel , under ½ in.
Ovary , comparatively broad in the middle, but tapering at either end.
Tube , narrow, a little more than an inch in length.
Falls , very narrow, probably yellow, about r½ in. long.
Standards , very narrow, 1 ½ in. long.
Styles , short and narrow.
Crests , linear, as long as the styles.

I have only seen one herbarium sheet of this species contammg five flowering stems and a tuft of leaves. It was impossible to say with certainty that the flowers were yellow, but this is probably their colour.

The species is easily distinguished by its extremely narrow segments. Its long tube brings it near to I. Purdyi and I. macrosiphon, but its stem is not concealed in bracts as is that of I. Purdyi (see Plate XI) and from I. macrosiphon it is separated by the longer stem, broader spathes and shorter tube.
Innes, C. (1985). The World of Iridaceae: 1-407. Holly Gare International Ltd., Ashington.


Limniris tenuissima (Dykes) Rodion., Bot. Zhurn. (Moscow & Leningrad) 92: 552 (2007).

Iris tenuissima var. purdyiformis R.C.Foster, Contr. Gray Herb. 119: 28 (1937).

Iris humboldtiana Eastw., Leafl. W. Bot. 2: 263 (1940).

Iris citrina Eastw., Leafl. W. Bot. 3: 125 (1942).

Iris tenuissima subsp. purdyiformis (R.C.Foster) L.W.Lenz, Aliso 4: 71 (1958).

Limniris purdyiformis (R.C.Foster) M.B.Crespo, Mart.-Azorín & Mavrodiev, Phytotaxa 232: 57 (2015).


Chromosome counts






Distribution and Cultivation

Distribution: Region:
Cultivation: seems to be the same as most bearded irises with perhaps a special emphasis on good drainage


Iris tenuissima-1a.jpgIrisTenuissima01.jpgIrisTenuissima02.jpgiristenuissima02.JPGIrisTenuissima03.jpgtenuissima01.JPG

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-- Main.RPries - 2010-03-02
I Attachment Action Size Date Who Comment
IrisTenuissima01.jpgjpg IrisTenuissima01.jpg manage 50 K 19 Sep 2014 - 19:24 Main.TLaurin Photo scanned from the Adele and Lewis Lawyer slide collection
IrisTenuissima02.jpgjpg IrisTenuissima02.jpg manage 84 K 19 Sep 2014 - 19:26 Main.TLaurin Photo scanned from the Adele and Lewis Lawyer slide collection
IrisTenuissima03.jpgjpg IrisTenuissima03.jpg manage 76 K 19 Sep 2014 - 19:28 Main.TLaurin Photo scanned from the Adele and Lewis Lawyer slide collection
Iris_tenuissima-1a.jpgjpg Iris_tenuissima-1a.jpg manage 77 K 08 Jun 2011 - 21:30 Main.ksayce Iris-tenuissima
iristenuissima02.JPGJPG iristenuissima02.JPG manage 321 K 31 Mar 2017 - 14:21 Main.TLaurin Photo by Jean Witt
tenuissima01.JPGJPG tenuissima01.JPG manage 679 K 06 Feb 2017 - 19:57 Main.TLaurin Photo scanned from the Glenn Corlew slide collection
Topic revision: r11 - 25 Mar 2022, TLaurin
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