Plant Species of San Jacinto Mountain: Key To High-Elevation Sedge (Carex) Species



Carex senta
swamp sedge
Our most common meadow sedge
 

Introduction to the Key
Key With Pictures
Key Without Pictures

 
Carex fracta
fragile sheath sedge
Our most widespread sedge


For an introduction to this page, and an extensive discussion, with pictures, of our two most common sedge species, see Plant Species of San Jacinto Mountain: Pictorial Identification Guide to High-Elevation Sedge (Carex) Species.

This page is an unfinished draft. The key without pictures is finished and ready to use.

The pictorial key needs to have most of the pictures added. However, a more useful page for beginners is the Plant Species of San Jacinto Mountain: Pictorial Identification Guide to High-Elevation Sedge (Carex) Species, which is what sidetracked me from finishing adding the rest of the pictures here.

Introduction to the Key

Carex keys normally use minute details of the perigynium, which can only be ascertained with a specimen in hand with mature fruit. In this key, I have tried as much as possible to use features more easily observed in the field or in photographs. However, since many Carex species are very similar in field appearance, in a few cases it is unavoidable to use the perigynium differences.

The key is presented twice; once with pictures illustrating the choices in each couplet, and once without the pictures.

Definition of some terms used in the key (if you use the pictorial key you may not need any of these definitions):

Inflorescence made of (mostly) separate male and female spikes

Definitions

Infl is the inflorescence, the part at the top of the flowering stalk that contains that flowers.

spike: the inflorescence is composed of several to many spikes, which are a close-packed agglomeration of male flowers, female flowers, or both sexes. Spikes are generally longer than wide, but not always.

Perigynium is a hard case that encloses the ovary and achene (seed), but which is usually hidden behind a flower bract until the plant begins to drop its seeds. It has a beak at its top end through which the styles emerge so that they can receive pollen. The beak often is bidentate, meaning it has two teeth, one on each side of the beak.

a bract or scale is a small somewhat-leaf-like membranous structure that usually covers most or all of the perigynium.

a glaucous leaf is covered with a whitish or grayish coating so that it appears whitish- or grayish-green, distinctly lighter than a normal green leaf.

pubescent means having hairs visible with a microscope or in a macro photograph.

a scabrous leaf blade has very short stiff hairs that fell rough to the touch when you run your hand along the margin of the leaf.

a glabrous leaf blade has no hairs at all and feels smooth to the touch.

cespitose means clumped, with many stems coming from the base of a separate plant.

staminate: the male flower, with anthers

pistillate: the female flower, with styles emerging from the perigynia.

pl: plant

lv, lvs: leaf, leaves.

fl, fls: flower, flowers.

Inflorescence made of tightly-packed spikes that have both male and female in the same spike, with the female on top

Key With Pictures

1. Infl with 3-7 spikes with all bases clearly separate, not overlapping; each spike often a single sex, all male or all female (go to #2)
1'. Infl with 4-35 spikes with at least some spike bases not clearly separate; every spike mostly with both sexes (go to #6)
2. Leaf blades (and perigynia) pubescent ... C. sartwelliana
2'. Leaf blades glabrous or scabrous on margins
3. Perigynia pubescent; spike 5-10 mm; pl low, matlike, infl often hidden amid lvs ... C. rossii
3'. Perigynia glabrous; spike 7-70 mm; pl tall, infl not hidden
4. Plant glaucous, not cespitose ... C. nebrascensis
4'. Plant green, cespitose ... (5)
5. Spikes 25-70 mm, ~5 x longer than wide; infl with 1-3 terminal all male spikes; stigmas 2 ... C. senta
5'. Spikes 7-27 mm, 2-3.5(5) x longer than wide; infl gen with no all male spikes; stigmas 3 ... C. heteroneura
6. Infl elongate, 2-5 x longer than wide
7. Distance between lowermost spikes >> 10 x spike lengths ... C. lemmonii
7'. Distance between lowermost spikes << 10 x spike lengths
8. Infl 3.5-5 x longer than wide, 2.5-8 cm long; spikes 7-35 ... C. fracta (and maybe C. mariposana)
8'. Infl 1.2-4 x longer than wide; 1-3 cm long; spikes 4-11(14)
9. Infl 1.2-2.2 x longer than wide, 1-2 cm long; perigynium tip reddish or brown, beak entire; perigynium veins extended above fruit ... C. abrupta2
9'. Infl 1.5-4 x longer than wide, 1-3 cm long; perigynium tip not reddish, beak serrate; perigynium veins not extended above fruit ... C. subfusca

6'. Infl capitate, 1-2 x longer than wide

10. Infl with lowermost bracts leaf-like, >> spikes ... C. athrostachya
10'. Infl with all bracts < spikes except sometimes lowest
11. Spikes staminate at tip, perigynia spreading
12 Scales dark brown with inconspicuous midrib; perigynium margin entire, nerved on both faces, 3-4 mm long, with shallowly bidentate beak, wall filled with pithy tissue below .. C. jonesii
12' Scales light- to red-brown, midrib conspicuous, greenish, extreme margin white; perigynium margin serrulate above middle, only faintly veined on inner face, 3.5-5 mm long, with sharply bidentate beak, wall not filled with pithy tissue .. C. hoodii
11'. Spikes pistillate at tip; perigynia erect to ascending
13. +- Dry areas, including dryish meadows; spikes 10-12 mm; pistillate bracts longer than perigynia; beak to top of fruit 2-2.8(-3.3) mm ... C. multicostata
13'. Moist areas; spikes 4.4-10.8 mm; pistillate bracts shorter than perigynia; beak to top of fruit (1.6-)2-2.3 mm ... C. abrupta2

Key Without Pictures

Print Version

1. Infl with 3-7 spikes with all bases clearly separate, not overlapping

2. Leaf blades (and perigynia) pubescent ... C. sartwelliana
2'. Leaf blades glabrous or scabrous on margins
3. Perigynia pubescent; spike 5-10 mm; pl low, matlike, infl often hidden amid lvs ... C. rossii
3'. Perigynia glabrous; spike 7-70 mm; pl tall, infl not hidden
4. Lateral spike 7-27 mm, 2-3.5(5) x longer than wide; terminal spikelet gen pistillate at tip, sometimes all staminate; lateral spikelets staminate at tip; stigmas 3 ... C. heteroneura
4'. Lateral spikes 24-70 mm, longest 5-10 x longer than wide; infl with 1-3 terminal all male spikes, lower lateral spikelets gen all pistillate; stigmas 2 ... (5)
5. Plant glaucous, not cespitose ... C. nebrascensis
5'. Plant green, cespitose ... C. senta

1'. Infl with 4-35 spikes with some spike bases not clearly separate

6. Infl elongate, 2-5 x longer than wide
7. Distance between lowermost spikes >> 10 x spike lengths ... C. lemmonii
7'. Distance between lowermost spikes << 10 x spike lengths
8. Infl 3.5-5 x longer than wide, 2.5-8 cm long; spikes 7-35 ... C. fracta (and maybe the very similar C. mariposana if it exists here)
8'. Infl 1.2-4 x longer than wide; 1-3 cm long; spikes 4-11(14)
9. Infl 1.2-2.2 x longer than wide, 1-2 cm long; perigynium tip reddish or brown, beak entire; perigynium veins extended above fruit ... C. abrupta2
9'. Infl 1.5-4 x longer than wide, 1-3 cm long; perigynium tip not reddish, beak serrate; perigynium veins not extended above fruit ... C. subfusca

6'. Infl capitate, 1-2 x longer than wide

10. Infl with lowermost bracts leaf-like, >> spikes ... C. athrostachya
10'. Infl with all bracts < spikes except sometimes lowest
11. Spikes staminate at tip, perigynia spreading
12 Scales dark brown with inconspicuous midrib; perigynium margin entire, nerved on both faces, 3-4 mm long, with shallowly bidentate beak, wall filled with pithy tissue below .. C. jonesii
12' Scales light- to red-brown, midrib conspicuous, greenish, extreme margin white; perigynium margin serrulate above middle, only faintly veined on inner face, 3.5-5 mm long, with sharply bidentate beak, wall not filled with pithy tissue .. C. hoodii
11'. Spikes pistillate at tip; perigynia erect to ascending
13. +- Dry areas, including dryish meadows; spikes 10-12 mm; pistillate bracts longer than perigynia; beak to top of fruit 2-2.8(-3.3) mm ... C. multicostata
13'. Moist areas; spikes 4.4-10.8 mm; pistillate bracts shorter than perigynia; beak to top of fruit (1.6-)2-2.3 mm ... C. abrupta2


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Updated 20 September 2010.