Key to Iris

View taxon page for Iris

(For a list of species in Iris, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Sepal obviously bearded ..... I. germanica

1' Sepal not obviously bearded

2. Perianth tube > 30 mm

3. Cauline leaves bract-like

4. Perianth pale cream-yellow with prominent brown-violet veins, rose-violet with darker veins, or ± white with rose veins; stigmas 

truncate 

Abruptly (not gradually) narrower or smaller at base or tip, as if cut straight across or nearly so.

, ± rounded, or 2-lobed ..... I. purdyi

4' Flowers pale yellow or cream with same color (or ± red) veins; stigmas triangular or tongue-shaped ..... I. tenuissima subsp. purdyiformis

3' Cauline leaves similar to 

basal 

At or near the base of a plant or plant part. Especially said of leaves clustered near the ground or of a placenta confined to the base of an ovary.

5. Stigmas tongue-shaped, tip rounded; 

rhizome 

1. In seed plants, stem that is often elongate, more or less horizontal, usually underground; distinguished from roots by bearing of leaves, leaf scars, axillary buds, etc. 2. In ferns, stem that is located underground, embedded in leaf litter, on rocks or in rock crevices, or on trees or tree branches, often scaly or hairy; distinguished from roots by bearing of fronds (roots rarely bear fronds), and their greater diameter.

2–5 mm diam

6. Stigmas 

entire 

Having margins that are continuous and smooth (i.e., without teeth, lobes, etc.).

; perianth parts 

elliptic 

In the shape of a flattened circle or ellipse; wider than linear

or narrowly elliptic; stem generally < 1 dm ..... I. chrysophylla

6' Stigmas finely toothed; perianth parts widely oblanceolate; stem >= 1 dm ..... I. tenuissima subsp. tenuissima

5' Stigmas triangular, tip 

acute 

Having a short-tapered, sharp tip, the sides convex or straight and converging at less than a right angle.

; rhizome 4–9 mm diam

7. Perianth tube 

funnel-shaped 

Widening from the base more or less gradually through the throat into an ascending, spreading, or recurved limb; often applied to a fused calyx or corolla.

; basal leaves >= 6 mm wide ..... I. fernaldii

7' Perianth tube abruptly inflated at top (bowl-like); basal leaves <= 6 mm wide ..... I. macrosiphon

2' Perianth tube < 30 mm

8. Stigmas 2-lobed; rhizomes 9–30 mm diam; cauline leaves bract-like for at least 2/3 length

9. Lowest bracts 

alternate 

1. Arranged singly, often spirally, along an axis - e.g., one leaf per node. 2. Occurring in different ranks, appearing to be between, not directly above or below, as 'stamens alternate petals'.

; moist, coastal prairie or open coastal forest; flowers 3–6, lilac-purple ..... I. longipetala

9' Lowest bracts 

opposite 

1. Arranged in pairs along an axis - e.g., two leaves per node. 2. Occurring in the same rank, directly above or below, as 'stamens opposite petals'. 3. Located directly across from.

; seasonally wet sites; flowers 1–2, pale lilac to ± white, or 2–9, brown, red-brown, or green

10. Basal leaves 25–35 mm wide; bracts not scarious; flowers 2–9, pale yellow to brown, red-brown, or green, veined green or red-brown ..... I. foetidissima

10' Basal leaves 3–9 mm wide; bracts generally scarious; flowers 1–2, pale lilac to ± white, veined lilac-purple ..... I. missouriensis

8' Stigmas triangular, tongue-shaped, or rounded; rhizomes 1–12 mm or 30–40 mm diam; cauline leaves bract-like or similar to basal

11. Stigmas rounded; basal leaves 20–35 mm wide; rhizomes 30–40 mm diam; wetlands ..... I. pseudacorus

11' Stigmas triangular or tongue-shaped; basal leaves 2–20 mm wide; rhizomes 1–12 mm diam; dry slopes (moist meadows)

12. Cauline leaves bract-like for at least 2/3 of length

13. Perianth tube <= 10 mm; cauline leaves overlapped; flowers generally 2 ..... I. bracteata

13' Perianth tube > 10 mm; cauline leaves generally not overlapped; flowers 1–2

14. Lowest bracts 

spreading 

Oriented more or less perpendicularly to the axis of attachment; often, more or less horizontal.

; ovary triangular, clearly winged

15. Ovary clearly winged; perianth with deep maroon or ± brown veins ..... I. tenax subsp. klamathensis

15' Ovary triangular but not winged; perianth lacking dark veins ..... I. hartwegii subsp. pinetorum

14' Lowest bracts enclosing perianth tube; ovary rounded or triangular, not winged

16. Flowers generally golden yellow; ovary rounded; petals elliptic ..... I. innominata

16' Flowers generally lavender to blue, occasionally ± white; ovary triangular; petals obovate ..... I. thompsonii

12' Cauline leaves similar to basal

17. Flowers pale cream to yellow or gold-yellow, veined gold or bright yellow or not

18. Flowers 3; outer 

bract 

Reduced, leaf- or scale-like structure subtending a branch, cone scale, peduncle, pedicel, or flower.

9–15 cm; perianth tube 11–15 mm ..... I. hartwegii subsp. columbiana

18' Flowers 2; outer bract 6–11 cm; perianth tube 5–10 mm ..... I. hartwegii subsp. hartwegii

17' Flowers blue to lavender or purple (white or pale cream), with cream or ± white throat or not

19. Basal leaves 7–10 mm wide; flowers 2; dry slopes ..... I. hartwegii subsp. australis

19' Basal leaves 10–22 mm wide; flowers generally > 2; grassy sites

20. Stem generally branched, flowers 2/branch; coastal plains ..... I. douglasiana

20' Stem unbranched, flowers 3; wet grassy sites in s SN ..... I. munzii

Please use this Google Form for Contact/Feedback

Citation for the whole project: Jepson Flora Project (eds.) . Jepson eFlora, https://ucjeps.berkeley.edu/eflora/ [accessed on ]

Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on .

We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The Jepson Herbarium.