Key to Oxalis

View taxon page for Oxalis

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

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

1. Petals yellow to yellow-orange, drying ± red or not

2. Annual; fruit < 5 mm ..... O. micrantha

2' Perennial herb; fruit >= 6 mm or 0

3. Leaves in loose, ± 

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.

 

rosette 

A radiating cluster of leaves generally at or near ground level.

; 

bulbs 

Short underground stem and the fleshy leaves or leaf bases attached to and surrounding it (e.g., an onion).

present ..... O. pes-caprae

3' Leaves cauline; bulbs 0

4. Petals 12–20 mm; NCo ..... O. suksdorfii

4' Petals 5–12 mm; NCo, elsewhere

5. Petals generally < 8 mm; taproot 

fibrous 

1. Pertaining to structures that are composed at least in part of more or less thread-like but usually tough elements (e.g., Yucca leaves). 2. Pertaining to a root system composed of many roots similar in length and thickness (e.g., grass roots).

; stem rooting at 

nodes 

Position on a stem from which one or more structures (especially leaves, buds, branches, or flowers) arise.

..... O. corniculata

5' Petals generally 8–12 mm; taproot ± woody; stem not rooting at nodes (sometimes rooting at nodes in O. pilosa)

6. Hairs generally sparse, 

appressed 

Parallel or nearly parallel to and often in contact with surface of origin; used to describe the disposition of hairs, leaves, pedicels, etc.

or arched upward; 

pedicels 

Stalk of an individual flower in an inflorescence, or the corresponding structure in fruit.

> 2 × fruit ..... O. californica

6' Hairs dense, generally 

spreading 

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

; pedicels < 2 × fruit ..... O. pilosa

1' Petals white to pink, red, purple-rose, or purple

7. Bulbs 0

8. Rhizome woody, not creeping; disturbed places ..... O. articulata subsp. rubra

8' Rhizome fleshy, creeping; ± undisturbed forests

9. Flowers 1 ..... O. oregana

9' Flowers 3–9 in umbel-like 

cyme 

1. In flowering plants excluding Asteraceae and some other groups, a branched inflorescence in which the central or uppermost flower opens before the peripheral or lowermost flowers on any axis. see 2. In Asteraceae and some other groups, a cyme-like inflorescence is one in which the central or uppermost inflorescence units (e.g., heads in Asteraceae, umbels enclosed by involucres in Eriogonum), instead of individual flowers, develop and mature before the peripheral or lowermost inflorescence units on any axis.

..... O. trilliifolia

7' Bulbs present

10. Stem elongate ..... O. incarnata

10' Stem ± 0

11. Flowers in umbel-like cyme ..... [O. bowiei]

11' Flowers 1 ..... [O. purpurea]

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