Spikes:

3 to 8 spikes each 4 to 10 mm (to 3/8 inch) long, all at the tip of the stem but not crowded, the upper spikes sometimes loosely overlapping and the lower more widely separated, the inflorescence (group of spikes) up to about 2 inches long and typically nodding or arching. All spikes are stalkless, erect to ascending, rounded at the tip, tapered at the base and club-shaped to elliptic in outline, with staminate (male) flowers at the base and pistillate (female) flowers at the tip (gynecandrous). At the base of the lowest spike is a scale-like bract with a bristle-like tip that may be longer than the spike and sometimes overtops the terminal spike

Leaves and stems:

Leaves are alternate with 3 to 5 leaves on the lower third of the stem, up to 14 inches long, 1.3 to 3 mm wide, flat, hairless, smooth or rough along the edges and midvein, and shorter than the flowering stems. Stem leaf sheaths tightly wrap the stem, are mostly green on the front with a Y-shaped, whitish translucent area up to 2 inches long at the tip that extends slightly above the leaf base and is straight to U-shaped across the top edge. Sheaths and sometimes the upper leaf surface are variably covered in minute bumps (papillose) especially near the sheath tip. The ligule (membrane where the leaf joins the sheath) is as wide as or wider than long.

Bases are wrapped in a pale brown to dark purple-brown sheath that may become fibrous, with old leaves often persisting to the next season. Stems are hairless, erect to ascending, 3-sided in cross-section, very slender, mostly smooth except just below the spikes. Stems may elongate to 40 inches at maturity and are longer than most leaves. Plants are clump forming from a mix of up to 40 flowering stems and a few vegetative shoots, the vegetative stems with 4 to 9 leaves mostly clustered near the tip.

Fruit:

Fruit develops in late spring to early summer, the spikes forming clusters of seeds (achenes), each wrapped in a casing (perigynium), subtended by a scale. Perigynia are mostly ascending. Each spike contains 10 to 30 fruits.

Pistillate scales are lance-oblong, translucent yellowish to brown-tinged with a green or brown midrib, blunt to pointed at the tip, narrower than and 80% to 100% as long as the perigynia. Perigynia are 2.7 to 4 mm long, 1.3 to 2 mm wide, brown at maturity, hairless, 5 to 8-veined on the front, 3 to 5-veined on the back (may be faint), flattened, not inflated, the body egg-shaped to broadly elliptic, widest at or below the middle, gradually or abruptly tapered to a beak .9 to 1.5 mm long, and has a thin, papery wing .2 to .4 mm wide around the edges that extends to the base but may be obscure until the perigynia dries down. Achenes are lens-shaped, brown at maturity, 1.3 to 1.6 mm long, .9 to 1.1 mm wide, elliptic; the distance from the tip of the achene to the tip of the beak is 1.3 to 2 mm.

Notes:

Carex tenera is a fairly common sedge found in about half the state, in a variety of habitats from rock outcrops to open meadows to shady woods to sandy shores, in dry to wet soils.

Carex is a large genus, with over 600 species in North America and 150+ in Minnesota alone. They are grouped into sections, the species in each group having common traits. Carex tenera is a member of the Ovales section, a notoriously difficult group. Some common traits are: usually clump forming, basal sheaths brown and somewhat fibrous, leaves V-shaped when young; 2 to 20 stalkless spikes all at the stem tip and crowded or not, spikes usually all pistillate at the tip and staminate at the base (gynecandrous), lowest bracts scale-like usually with a bristle tip, pistillate scales blunt to pointed at the tip and sometimes awned; perigynia erect to spreading, hairless, veinless to conspicuously veined on one or both surfaces, flat, beaked, usually with a translucent, papery wing; achenes lens-shaped.

Some traits to look at in Ovales are whether spikes are all crowded at the tip or more loosely arranged, whether the inflorescence is nodding or mostly erect, the shape of the spike (round vs. elliptic vs. club-shaped), the size and shape of the perigynia particularly the body (e.g. round vs. elliptic), the width of the wing and whether it extends all the way to the base, whether there are distinct veins on one or both sides of the perigynia, the length of the pistillate scale relative to the perigynia, the shape of the achene, leaf width, and whether sheaths are papillose, but strong magnification (30x or more) is required to see this. Habitat can also be a factor, and a metric scale is essential since fractions of millimeters make a difference.

Carex tenera is distinguished from other Minnesota Ovales species by widest leaves less than 3 mm wide, tight sheaths, the sheaths and sometimes upper leaf surface sparsely to densely papillose; 3 to 8 spikes in a nodding or arching inflorescence, spikes not crowded and the lower spikes may be more separated than the upper, spikes rounded at the tip and tapered at the base, lowest perigynia on a spike ascending; pistillate scales 80% to 100% as long as the perigynia; perigynia 2.7 to 4 mm long, the body broadly elliptic to egg-shaped, veined on both sides (sometimes faintly), the wing .2 to .4 mm wide extending all the way to the base. The distance from the tip of the achene to the tip of the beak is 1.3 to 2 mm. It is found in wet to dry soil, sun to shade.

Carex tenera can be very difficult to distinguish from C. echinodes; until recently they were considered varieties of the same species (C. tenera var. echinodes and var. tenera) and share many of the same traits. The pistillate scales of C. echinodes are shorter (60% to 85% as long as the perigynia), its sheaths and leaves are not papillose, its perigynia tend to be proportionately narrower with a longer beak and are more widely spreading on the spike. Also very similar is C. normalis, which has widest leaves usually more than 3 mm, sheaths with distinct cross-partitions between the veins and not pappilose, usually a straighter, stiffer and more compact inflorescence, spikes are more rounded at the base with few staminate flowers.

The nodding inflorescence is similar to several other members of Ovales, in particular C. projecta, C. foenea and C. scoparia, which may have more than 8 spikes, widest leaves more than 3 mm, loose sheaths, sheaths are not papillose, or perigynia are larger.