Amaryllidaceae
Amaryllidaceae, the amaryllis or onion family, is a large and diverse family of monocots in the order Asparagales, containing about 75 genera and over 2,000 species. As broadly defined by the APG system (sensu lato), it includes the traditional Amaryllidaceae, the former Alliaceae (onion family), and Agapanthaceae. Members are typically perennial herbs growing from bulbs (sometimes rhizomes), usually with basal, linear leaves. The characteristic inflorescence is an umbel-like cyme borne on a leafless scape and subtended by spathe bracts. Flowers usually have 6 tepals and 6 stamens. Ovary position is key: typically inferior (Amaryllidoideae, Agapanthoideae) but superior in the Alliodeae subfamily (Allium and relatives). Fruit is usually a capsule.
Overview
The Amaryllidaceae family, in its modern broad sense, is nearly cosmopolitan, with major centers of diversity in southern Africa, the Andes region of South America, and the Mediterranean basin. This phylogenetic grouping unites morphologically distinct lineages based on strong molecular evidence. The subfamily Amaryllidoideae includes many popular ornamentals like daffodils (Narcissus), amaryllis (Hippeastrum), snowdrops (Galanthus), spider lilies (Lycoris), and belladonna lilies (Amaryllis), often characterized by showy flowers and specific alkaloids. The subfamily Allioideae encompasses the economically vital genus Allium (onions, garlic, chives, leeks, shallots) along with related genera, defined by their superior ovaries and characteristic sulfur-containing compounds responsible for their pungent flavors and aromas. The small subfamily Agapanthoideae contains only the genus Agapanthus (African lilies or Lily of the Nile), popular rhizomatous ornamentals with umbels of blue or white flowers and superior/half-inferior ovaries.
Economically, the family is hugely significant for food and flavoring (Allium) and as a source of globally popular ornamental bulbs and perennials. Some Amaryllidoideae alkaloids have medicinal applications (e.g., galantamine from Galanthus used for Alzheimer's disease), but many are also toxic. The characteristic scapose umbel surrounded by spathe bracts is a common feature uniting most members, despite differences in ovary position and chemistry between the subfamilies.
In Oklahoma (current location as of March 27, 2025), several species of wild onions and garlic (Allium) are native and common, flowering in spring or summer. Daffodils (Narcissus) are widely planted and frequently persist or naturalize near old homesites, providing early spring color.
Quick Facts
- Scientific Name: Amaryllidaceae J.St.-Hil. (sensu lato)
- Common Name: Amaryllis family, Onion family
- Number of Genera: Approximately 70-80
- Number of Species: Approximately 1,600-2,250
- Distribution: Nearly cosmopolitan; centers of diversity in South Africa, Andean South America, Mediterranean basin.
- Evolutionary Group: Monocots (Lilioid Monocots)
- Order: Asparagales
- Subfamilies: Agapanthoideae, Allioideae, Amaryllidoideae
Key Characteristics
Growth Form and Habit
Mostly perennial herbs regenerating from bulbs (often tunicated - covered in dry, papery layers), sometimes from rhizomes (Agapanthus, some Allium) or corms. Possess contractile roots that pull bulbs/corms deeper into the soil.
Leaves
Leaves are usually basal, arising directly from the bulb or rhizome, though sometimes cauline (borne on an aerial stem). They are simple, typically linear or strap-shaped, sometimes terete (circular in cross-section, e.g., chives) or broader. Venation is parallel. Leaf bases are sheathing. Leaves often fleshy and may wither before or after flowering. In Allioideae, leaves frequently produce characteristic onion or garlic odors (allyl sulfides) when crushed.
Inflorescence
The characteristic inflorescence is a terminal cluster appearing as an umbel (though technically often a contracted/helicoid cyme) borne at the apex of a leafless stalk called a scape. This umbel is typically subtended by and enclosed in bud by two or more (sometimes one) membranous or papery spathe bracts. Flowers are sometimes solitary (Galanthus, some Narcissus) but still typically on a scape with spathe bracts.
Typical Amaryllidaceae inflorescence: an umbel-like cyme on a leafless scape, subtended by spathe bracts.
Flowers
Flowers are usually bisexual, typically actinomorphic (radially symmetric) but sometimes slightly zygomorphic (e.g., Narcissus, Alstroemeria - latter now separate family). Typically 3-merous perianth and androecium. Often large and showy, but can be small (Allium).
- Perianth: Composed of 6 petal-like tepals arranged in two whorls of 3 (3+3). Tepals can be free (distinct) or fused at the base into a perianth tube of varying length. In Narcissus, a prominent corona (trumpet or cup-like outgrowth) arises from the perianth tube or tepal bases, which is highly characteristic. Colors are diverse (white, yellow, pink, red, orange, blue/purple).
- Androecium: Stamens number 6 (rarely fewer or more), arranged in two whorls of 3. Filaments are free or attached to the perianth tube, sometimes fused basally to form a staminal cup, or bearing appendages. Anthers typically open via longitudinal slits.
- Gynoecium: Ovary position is key for subfamilies: typically inferior in Amaryllidoideae and Agapanthoideae, but characteristically superior in Allioideae. Composed of 3 fused carpels forming 3 locules with usually numerous ovules on axile placentas. A single style terminates in a capitate or slightly 3-lobed stigma. Nectar is usually produced by septal nectaries within the ovary walls.
Flower with inferior ovary (Amaryllidoideae/Agapanthoideae). Note corona in Narcissus.
Flower with superior ovary (Allium, Allioideae).
Fruits and Seeds
The fruit is predominantly a loculicidal capsule (splitting longitudinally into the locules) containing few to numerous seeds. Less commonly, the fruit is a berry. Seeds are often flattened or subglobose, typically blackish due to phytomelan pigment in the seed coat (characteristic of Asparagales). Seeds sometimes winged or possess a fleshy appendage (elaiosome) for ant dispersal. Endosperm is present, often fleshy or hard.
Chemical Characteristics
Chemical profiles differ significantly between subfamilies:
- Amaryllidoideae: Characterized by a unique class of isoquinoline alkaloids known as Amaryllidaceae alkaloids (e.g., lycorine, galantamine, narciclasine). Many are physiologically active and potentially toxic.
- Allioideae: Defined by the presence of sulfur-containing compounds (allyl sulfides, cysteine sulfoxides) that produce the characteristic onion and garlic odors and flavors upon tissue damage. Saponins are also common.
- Agapanthoideae: Contain steroidal saponins.
Identification Basics
Identifying Amaryllidaceae (sensu lato) involves recognizing the bulbous habit, scapose umbel, 6-merous flowers, and then checking ovary position and chemistry (scent) to distinguish subfamilies.
Primary Identification Features
- Habit: Perennial herbs, typically from bulbs (sometimes rhizomes).
- Leaves: Usually basal, linear or strap-shaped, parallel-veined.
- Inflorescence: Flowers typically in an umbel-like cyme at the top of a leafless scape, subtended by spathe bracts.
- Flowers: Usually 6 petaloid tepals and 6 stamens.
- Ovary Position: Inferior (most Amaryllidoideae, Agapanthoideae) OR Superior (Allioideae - Allium & relatives).
- Fruit: Typically a capsule.
- Chemistry (Subfamily Clues): Onion/garlic scent (Allioideae) vs. lack of scent or presence of specific alkaloids (Amaryllidoideae).
Secondary Identification Features
- Corona: Presence of a trumpet or cup-like corona (Narcissus).
- Tepal Fusion: Tepals free or fused into a tube.
- Spathe Bracts: Number and appearance (papery, green).
- Bulb Structure: Tunicate (papery layers) or scaly.
- Seed Color: Often blackish (phytomelan).
Seasonal Identification Tips
- Spring: Peak flowering for many important genera like Narcissus, Galanthus, Leucojum, and many Allium.
- Summer: Flowering continues for other Allium, Agapanthus, Lycoris (sometimes late summer/fall). Leaves may senesce after flowering in some bulbous species.
- Fall: Some species like Amaryllis belladonna, Sternbergia, Nerine, certain Lycoris flower in fall, often before leaves emerge.
- Winter: Dormant as bulbs or rhizomes.
- (Oklahoma Context: Native Allium species flower spring/summer. Naturalized Narcissus are prominent in early spring. Other members typically only seen in cultivation).
Common Confusion Points
- Liliaceae (Lily Family): Also often bulbous with 6 tepals, 6 stamens. Key differences: Ovary always superior; inflorescence usually a raceme, panicle, or solitary flower (not typically a scapose umbel with spathes); different chemistry.
- Iridaceae (Iris Family): Also often bulbous/cormous/rhizomatous with 6 tepals, inferior ovary. Key differences: Only 3 stamens; leaves often equitant (flattened in one plane).
- Asparagaceae (Asparagus Family, broad sense): Extremely diverse; subfamily Scilloideae (Hyacinths, Squills) is bulbous with 6 tepals, 6 stamens, superior ovary, but flowers typically in racemes or spikes, lack onion scent. Agavoideae (Agave, Yucca) are succulent rosette plants with different inflorescences.
- Colchicaceae (Meadow Saffron Family): 6 tepals, 6 stamens, superior ovary, capsule fruit, often from corms. Key differences: Typically 3 distinct styles (vs. single style in Amaryllidaceae); different alkaloids (colchicine); inflorescence often different.
Focus on: Bulbous habit + Scapose Umbel + Spathe Bracts + 6 Tepals + 6 Stamens + Ovary Position (Inferior or Superior) + Chemistry (Onion Scent?).
Field Guide Quick Reference (Amaryllidaceae s.l.)
Look For:
- Herbaceous perennial, usually from bulb
- Leaves usually basal, linear/strap-like
- Inflorescence umbel-like, on scape, with spathe(s)
- Flowers 6 tepals, 6 stamens
- Ovary Inferior (Amaryllidoideae, Agapanthoideae)
- Ovary Superior (Allioideae - Allium etc.)
- Fruit usually a capsule
Key Subfamily Clues:
- Allioideae: Superior ovary + Onion/garlic scent
- Amaryllidoideae: Inferior ovary + No onion scent + Often Amaryllidaceae alkaloids + Corona (Narcissus)
- Agapanthoideae: Inferior/superior ovary + Rhizome + No onion scent + Saponins (Agapanthus)
Notable Examples
The Amaryllis/Onion family includes vital food plants and spectacular ornamentals.
Allium canadense
Wild Garlic / Meadow Garlic
A perennial herb native to eastern and central North America, including Oklahoma. Grows from a bulb, producing narrow, flat or channeled leaves and a scape topped by an umbel of pinkish or white flowers, often replaced partially or entirely by small bulbils. Crushed foliage has a distinct garlic/onion scent. Represents subfamily Allioideae (superior ovary).
Narcissus pseudonarcissus
Wild Daffodil / Trumpet Daffodil
A perennial herb native to Western Europe, the parent species of many cultivated daffodils, often naturalized near old gardens. Grows from a bulb. Features strap-like basal leaves and a scape bearing a solitary (or few) flower(s) subtended by a papery spathe. Flower has 6 pale yellow tepals and a prominent, darker yellow, trumpet-shaped corona. Ovary inferior (Amaryllidoideae).
Amaryllis belladonna
Belladonna Lily / Naked Lady
A bulbous perennial native to South Africa. Famous for flowering in late summer/fall after the strap-like leaves have withered ('naked'). Produces a stout scape bearing an umbel of large, fragrant, trumpet-shaped pink flowers. Ovary inferior. Note: The common potted 'Amaryllis' is usually Hippeastrum.
Hippeastrum Hybrids
Common 'Amaryllis'
Native to South America, these bulbous perennials are widely sold, especially around winter holidays, for their enormous, showy, trumpet-shaped flowers (red, pink, white, striped) borne on thick, hollow scapes, usually appearing before or with the strap-like leaves. Ovary inferior (Amaryllidoideae).
Galanthus nivalis
Common Snowdrop
A small bulbous perennial native to Europe, one of the earliest spring flowers. Features narrow basal leaves and a scape bearing a solitary, nodding white flower subtended by a spathe. Flower has 3 larger outer tepals and 3 smaller inner tepals often marked with green. Ovary inferior (Amaryllidoideae).
Agapanthus africanus
African Lily / Lily of the Nile
A rhizomatous perennial native to South Africa, widely cultivated in mild climates. Features strap-like basal leaves forming clumps. Produces tall scapes topped by large, dense umbels of numerous funnel-shaped blue or white flowers. Ovary superior or half-inferior. Represents subfamily Agapanthoideae.
Phylogeny and Classification
Amaryllidaceae is a major family within the large monocot order Asparagales, part of the Lilioid monocot clade (distinct from Commelinids). Molecular phylogenetics fundamentally reshaped the family, demonstrating that three groups previously treated as distinct families – Amaryllidaceae sensu stricto (inferior ovary, specific alkaloids), Alliaceae (superior ovary, onion scent), and Agapanthaceae (Agapanthus) – form a single, strongly supported monophyletic group. Consequently, APG systems unite them as subfamilies (Amaryllidoideae, Allioideae, Agapanthoideae) within a broadly defined Amaryllidaceae.
Within Asparagales, the sister relationship of Amaryllidaceae sensu lato is often placed with Asparagaceae sensu lato (another huge, redefined family). The order Asparagales itself is highly diverse, also including Orchidaceae and Iridaceae. The unification of Amaryllidaceae highlights how molecular data can reveal evolutionary connections despite significant divergence in key morphological traits (like ovary position) and chemical profiles (Amaryllidaceae alkaloids vs. Allium sulfur compounds).
Position in Plant Phylogeny
- Kingdom: Plantae
- Clade: Angiosperms (Flowering plants)
- Clade: Monocots
- Order: Asparagales
- Family: Amaryllidaceae (sensu lato)
- Subfamilies: Agapanthoideae, Allioideae, Amaryllidoideae
Evolutionary Significance
The expanded Amaryllidaceae demonstrates significant evolutionary diversification within the Asparagales order. Key themes include the recurrent evolution of the bulb geophyte habit (adaptation to seasonal climates), the widespread success of the scapose umbel inflorescence (often associated with specific pollinators or providing floral display), the divergence in ovary position (superior vs. inferior), and the development of distinct, potent chemical profiles (alkaloids vs. sulfur compounds) likely related to defense and ecological interactions. The family provides excellent examples of how molecular data resolved long-standing questions about relationships between morphologically disparate but evolutionarily related groups.
