keys to the vascular plants of east texas - Botanical Research ...

ALLIUM/ALLIACEAE
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pounds are antibacterial or antifungal; others inhibit blood clotting. The sulfur-containing
compounds are effective as feeding deterrents to animals (Rahn 1998a). Alliums are being researched
for medicinal uses (e.g., antibacterial, antifungal, anti-inflammatory, antiseptic, anticoagulant,
etc.), and some (e.g, garlic, onions) have been shown to be effective against the
buildup of cholesterol in the blood (Cheatham & Johnston 1995). The following key relies in
part on characteristics of the bulbs, including the bulb coats. Specimens should therefore include
the entire bulb and should not be “cleaned up” prior to pressing. Garlic has many cloves,
while onions have an undivided bulb—hence the derivation of the word onion—the single bulb
was probably referred to as unio (Latin: uni, one), later union, and eventually onion (in English)
and oignon in French (Davies 1992). (The ancient Latin name for garlic, from Celtic: all, hot or
pungent; this classic usage is still reflected in the words used for garlic in several modern languages—Italian,
aglio, and Spanish, ajo—Davies 1992)
REFERENCES: Fraser 1939; Ownbey 1951; Moore 1954–1955; Ownbey & Aase 1955; Di Fulvio 1973;
Howard 1990; Davies 1992; Hanelt 1996; Linne von Berg et al. 1996; Mathew 1996; Mes et al. 1997
[1998]; Ronsheim 1997; Gregory et al. 1998; Ohri et al. 1998; Stevenson et al. 1999; McNeal &
Jacobsen 2002.
1. Leaf blades hollow, circular in cross section or nearly so; flowering stems to more than 1 m tall;
introduced species.
2. Flowering stems inflated below the middle, 3–20(–30) mm in diam.; leaf blades 5–15(–20)
mm in diam.; bulbs usually � 2 cm in diam., only 1–3 per plant; umbel usually without bulbils ____ A. cepa
2. Flowering stems slender, not inflated below the middle, 4 mm or less in diam.; leaf blades 1–
5 mm in diam.; bulbs 1–2 cm in diam., clustered, typically 5–20 per plant; umbel usually
with at least some bulbils ________________________________________________________ A. vineale
1. Leaf blades flat, folded, or concave; flowering stems usually 0.5(–0.9) m or less tall (except taller
in A. ampeloprasum and A. sativum); native and introduced species.
3. Umbel with bulbils (= small asexual bulbs produced in an inflorescence), often with few or no
flowers; the few flowers, if present, rarely producing capsules or seeds.
4. Flowering stems naked above the subbasal leaves, usually 0.5(–0.9) m or less tall; bulb
coats with fibers that persist as a conspicuous net-like structure enclosing the bulbs; leaf
blades 1–5 mm wide; involucral bracts subtending umbel not narrowed to a beak; widespread
native species __________________________________________ A. canadense var. canadense
4. Flowering stems with leaves nearly to middle, often 0.5–2 m or more tall; bulb coats lacking
a net of persistent fibers; leaf blades 5–24(–40) mm wide; involucral bract(s) subtending
umbel narrowed to an elongate beak; persisting or escaped introduced species.
5. Underground bulb usually with ca. 2–few main cloves and numerous small (ca. 1 cm long),
yellowish or brownish, typically stalked bulblets from the base; bracts subtending umbel
2–5, persistent; stamens equaling or usually slightly exserted beyond the perianth
segments; umbel usually large, (3–)5–10 cm in diam. ________________________ A. ampeloprasum
5. Underground bulb without small bulblets but usually with 5–18+ similar-sized large
bulblets (= cloves); bract subtending umbel solitary, falling early; stamens included or
just equaling perianth segments; umbel usually 5 cm or less in diam. _________________ A. sativum
3. Umbel without bulbils; flowers producing capsules and seeds.
6. Leaves 5–24(–40) mm wide; flowering stems EITHER 3-angled OR with leaves nearly to the
middle; escaped introduced species.
7. Plants 45–200 cm tall; flowering stems round, with 4–10 leaves borne nearly to middle
of stem; perianth segments white to pink or reddish pink, 5.5 mm or less long ____ A. ampeloprasum
7. Plants 20–50(–60) cm tall; flowering stems 3-angled, naked above the 2–3 subbasal leaves;
perianth segments white, 7–12 mm long __________________________________ A. neapolitanum
6. Leaves 1–5(–7) mm wide; flowering stems round or nearly so (definitely not 3-angled) AND
naked above the subbasal leaves; widespread native species.