Key to Acaena

View taxon page for Acaena

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

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

1. Inflorescence a 

spike 

1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, an unbranched inflorescence in which the flowers are sessile and nearly always open from the bottom to the top of the inflorescence. 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a spike-like inflorescence is one in which the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are sessile 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.

; 

hypanthium 

Structure generally in the shape of a tube, cup, or bowl, derived from the fused lower portions of the perianth and stamens, from which these parts seem to arise, and to which the ovary wall is fused in an inferior ovary (to which the ovary wall is partially fused in a half-inferior ovary; from which the ovary is free in a superior ovary).

 prickles in fruit > 4, longest generally 1–3 mm, ± throughout; plant from ± woody, branched 

caudex 

Generally short, sometimes woody, more or less vertical stem of a perennial, at or beneath ground level.

; leaflets pinnately dissected ..... A. californica

1' Inflorescence a 

head 

1. A dense, often spheric inflorescence of sessile or subsessile flowers.
2. In Asteraceae and some other groups, a head-like inflorescence is one in which sessile or subsessile inflorescence units (e.g., heads in Asteraceae, umbels enclosed by involucres in Eriogonum), instead of individual flowers, are attached in a short dense cluster without an evident axis or branches.

; hypanthium prickles in fruit 4, longest 7.5–15 mm, ± on top; plant from stolons; leaflets toothed

2. Hypanthium in fruit with longest prickle 7.5–12 mm, without vestigial prickles below top; stem 1–2 mm diam; leaflets dull, smooth adaxially, generally ± glaucous abaxially ..... A. novae-zelandiae

2' Hypanthium in fruit with longest prickle 9–15 mm, generally with a few vestigial prickles below top; stem 2–3 mm diam; leaflets shiny, wrinkled adaxially, pale with uneven wax layer abaxially ..... A. pallida

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