Key to Thalictrum

View taxon page for Thalictrum

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

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

1. Plant 5–15(20) cm; leaves 

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.

(1 cauline), 1.5–6 cm; inflorescence 

raceme 

In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, an unbranched inflorescence in which the flowers are borne on pedicels and nearly always open from the bottom to the top of the inflorescence. 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a raceme-like inflorescence is one in which the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are stalked and attached directly to the main axis of the inflorescence, not to branches, and in which floral development may or may not proceed as in 1.

; 

pedicel 

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

 

recurved 

Gradually curved downward or backward.

in fruit ..... T. alpinum

1' Plant 40–200 cm; leaves basal and cauline, 4–46 cm; inflorescence generally 

panicle 

1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, a branched inflorescence in which the basal or lateral flowers (or some of them) open before the terminal or central flowers on any axis. 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a panicle-like inflorescence is one in which at least some of the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are attached (stalked or unstalked) to branches and not directly to the main axis of the inflorescence and in which floral development may or may not proceed as in 1.

; pedicel ± 

erect 

Upright; vertically oriented.

in fruit

2. Flowers 

bisexual 

Both male and female reproductive parts occurring and functional in the same plant or structure (e.g., flower, spikelet, inflorescence).

; filaments flat; anthers 

obtuse 

Having a short-tapered, blunt tip or base, the sides convex or straight and converging at more than a right angle.

to mucronate; fruit body sides generally semicircular to crescent-shaped, beak 1–1.5 mm ..... T. sparsiflorum

2' Flowers unisexual; filaments thread-like; anthers 

acuminate 

Having a long-tapered, sharp tip, the sides concave.

; fruit body sides obliquely narrowly 

ovate 

Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf.

to 

fusiform 

Elongate, widest at the middle, tapered to both ends.

or widely obovate to ± round, beak 1.5–4.5 mm

3. Fruit generally 

reflexed 

Abruptly bent or curved downward or backward.

, ribs ± straight; n NCo, nw KR ..... T. occidentale

3' Fruit 

spreading 

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

to 

ascending 

Curving or angling upward from base, or about 30-60 degrees less than vertical or away from axis of attachment.

, ribs ± curved; n NCo, nw KR, and elsewhere ..... T. fendleri

4. Fruit body ± 

compressed 

Flattened side-to-side or front-to-back.

throughout, sides obliquely ± ovate to ± obovate, 2–3-ribbed, veins 0; distal leaves abaxially generally finely glandular-puberulent (at 20×) ..... var. fendleri

4' Fruit body compressed generally only near margins, sides obliquely ± widely obovate to ± round, generally 1-ribbed, veins several, wavy, net-like; distal leaves abaxially generally glabrous ..... var. polycarpum

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