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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

LYTHRUM LOOSESTRIFE
Annual, perennial herb. Stem: prostrate to erect, often 4-angled. Leaf: opposite, alternate, or whorled, linear to ovate or obovate, petiole 0 to short. Inflorescence: flowers generally 1–2 per axil, sessile or not. Flower: radial to ± bilateral, of 1–3 style forms (heterostylous); hypanthium cylindric or bell-shaped, ribs generally conspicuous; sepals 4–6, deltate, epicalyx lobes < to > sepals; petals 4–6 or 0; stamens 4–6 or 12, included or exserted; styles < to > stamens. Fruit: capsule, generally cylindric, rarely spheric, valves 2. Seed: many, < 1 mm.
± 35 species: temperate. (Greek: clotted blood) [Houghton-Thompson et al. 2005 Ann Bot (London) 96:877–885]
Unabridged etymology: (Greek: clotted blood, from use of Lythrum salicaria, the first named sp., to stop hemorrhaging, according to Gerard, Bull Torrey Bot Club 12: 60. 1885)

Key to Lythrum

1. Hypanthium broadly bell-shaped, 1–2 mm, ribs conspicuous or not; stem extensively creeping or decumbent, rooting at nodes ..... L. portula

1' Hypanthium cylindric, 4–7 mm, ribs conspicuous; stem prostrate or ascending to erect, rooting at base

2. Flowers > 2 per axil, in dense, ± sessile cymes, not on short axillary shoots ..... L. salicaria

2' Flowers 1–2 per axil, on short axillary shoots or not

3. Stem erect, branches many, above; epicalyx lobes < to > sepals, horn-like; perennial herb ..... L. californicum

3' Stem decumbent to ascending or erect, branches at base, generally 0–few above; epicalyx lobes >> to = sepals; annual or short-lived per

4. Flowers 1 per axil, not on short axillary shoots; hypanthium 4–5 × longer than wide; epicalyx lobes ± 2 × > sepals ..... L. hyssopifolia

4' Flowers 1 per axil on main shoots and on short axillary shoots; hypanthium 8–10 × longer than wide; epicalyx lobes ± = sepals ..... L. tribracteatum

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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