TEK - Taxonmic key to Datura and Burgmansia

[Potter]

Introduction
The following classification key will aid in identifying Datura species. It is based primarily upon the chart appearing on p. 111 of Engelstrompeten, which, itself, is based on the work of Hammer, Romeike, and Tittel (Kulturpflanze 31: 13-75, 1983).

If you disagree with any of the taxonomic assignments we have made, please send us an email. Datura classification is complex and critical discussions helps to clarify it. We welcome your comments!

Credits
Dr. Richard Sanders, the Plant Sciences Director of the American Brugmansia and Datura Society (ABADS), is the original author of the classification key.

Erowid.org maintains vaults of information about both Datura and Brugmansia and created the current version of the classification key in May, 2002. Several new photos were added and some revisions and additions were made to the existing photos and text.

Copyrights
Images from a variety of resources are used in this guide. The majority are photos taken by Dr. Richard Sanders of plants in his own garden, or photos taken by Erowid. Photos from the key are copyrighted and are the property of their photographer. Photos by Richard Sanders or Erowid, which are displayed directly on pages of the classification key, are available for non-commercial use as long as they retain full credit to the photographer. Larger resolution images, linked to from the key, require permission for use. For commercial use of images, special permission is also required.

A. Plants are herbaceous. May become somewhat
woody. Calyx points above the horizontal upon
emergence of the corolla*, and flowers are
generally erect.

* Assuming the flowers fully emerge. D. leichhardtii often has flowers that do not extend and open before pollination occurs. As a result, the flower and calyx nod without the flower ever being fully exposed.

B. Fruit deflexed. (nodding) either with spines or no spines.
C. Fruit smooth with no spines and indihescent
doesn't split open by itself) or dihescing irregularly.........Datura ceratocaulis
CC. Fruit with spines or tubercles (bumps).
Fruit dihesces (splits open) regularly into four
sections and does not separate from its
circular base ("disk" or "cup"), or crumble spontaneously.
Corollas white with inside throat tinged purple...........Datura discolor
CCC.Fruit opens irregularly, crumbles or sections
detach from the circular base upon opening.
Fruit with tubercles or short, broad spines...............Datura metel
CCCC. Fruit with mostly sharp, prickly spines.
D. Flowers relatively small, about 2.5-3" long...............Datura leichhardtii
DD.Flowers relatively large, exceeding 4"...................Datura innoxia

BB. Fruit capsule erect, either with rigid spines or no spines.
Corolla limb mostly rounded or pentagonalwith five primary teeth.
Capsule has spines of almost equal-length, or capsule is smooth.....Datura stramonium
BBB.Spines on capsule are sturdy, longest at the top of the capsule.
c. Upper spines nearly as long as capsule.
Leaves ovate or oblong, dentate or angled.Flowers are white......Datura ferox
cc.Upper spines about 1/3 the length of capsule.
Leaves are pinnately-lobed, like an oak leaf
Flowers are white and tinged with violet....................Datura quercifolia
AA. Plants are treelike. Flowers are pendulous or
nodding below the horizontal. The calyx nods to
horizontal or below when the corolla first emerges.........Genus Brugmansia

While the Brugmansia key is incomplete, the primary Brugmansia species are described below.

Brugmansia arborea.
Flowers 4.5 - 6.5 inches long with white corollas. Corolla teeth are separated by distinct notches, making the flower appear to have "petals".

B. arborea grows as a shrub or small tree (6 - 15 ft.) and has softly hairy young stems, leaves, calyx, and fruit. The fruit is round to egg-shaped and 2.5 - 3.5 inches long.
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Brugmansia aurea.
Flower 7 - 9 inches (19 - 25 cm) long, and highly fragrant. Corolla white or gold-yellow, nodding to pendulous. Corolla teeth recurve backward. Calyx possess 2 - 5 teeth with no space between calyx and corolla.
B. aurea is a small tree reaching 35 feet tall has smooth or mildly hairy leaves. Fruit is egg shaped, 3-6 inches long.
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Brugmansia sanguinea.
Flowers 7 - 10 inches (16 - 25 cm) long and tubular only flaring a small amount. Corolla recurved, orange to red with yellow base. No space between calyx and corolla. Sepals are split two to five times.
B. sanguinea is a small tree reaching 35 feet, with softly hairy leaves. Fruit is egg shaped 3 - 5 inches long.
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Brugmansia suaveolens.
Flowers up to 12 inches (30 cm) long. Corolla white (sometimes pink or yellow), with a short constricted tube just above the calyx. Calyx 2 - 5 toothed. A highly-frangrant variety that is perfect for the moon garden.
B. suaveolens is a small tree 6 - 15 feet tall. Leaves are smooth edged (no teeth), either smooth-textured or with minute hairs. This variety was one of the first to gain popularity in Europe, especially during the Victorian era.
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Brugmansia versicolor.
Large pendulous flowers are 12-18 inches (30-50 cm) long. Corolla typically white changing with age to apricot or peach-pink, trumpet-shaped, with the tube constricted well beyond the calyx. Calyx has a single split. Corolla teeth are long, flaring and recurved. Highly fragrant at night.
B. versicolor is a small tree 8 - 15 feet tall with smooth edged leaves. Fruit is spindle-like and 6-12 inches long.
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Brugmansia vulcanicola.
Flowers tubular and 6-9 inches (15-25 cm) long, and nodding. Corolla ranging from yellow to orange, green near base. Calyx usually drops as the Corolla matures.
B. vulcanicola is a small tree up to 10 feet tall. Leaves are oval with smooth or toothed edges. Fruit is oval and warty.


Brugmansia Hybrids
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Brugmansia versicolor x suaveloens.
This hybrid was produced by Rich Sanders at the University of Connecticut EEB Greenhouse. It has intermediate characteristics between the brugmansia shown above (the mother plant) and B. versicolor 'apricot peach' (pollen source). White is the dominant color for hybrids when crossing these species of brugs.
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Brugmansia x insignis 'Pink'
Brugmansia x candida 'double white'
The "x insignis" hybrids are formed by producing the versicolor x suaveolens cross as above, then backcrossing with suaveolens to emphasize its character traits. "x candida" is produced by crossing B. versicolor with B. aurea. Of all the brugmansia types, x candida is the most abundant producer of double/multiple flowers.
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Brugmansia x insignis ''double white'
The "x insignis" hybrids are formed by producing the versicolor x suaveolens cross as above, then backcrossing with suaveolens to emphasize its character traits. "x candida" is produced by crossing B. versicolor with B. aurea. Of all the brugmansia types, x candida is the most abundant producer of double/multiple flowers.
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"Opening Night" - B. x insignis 'Frosty Pink',
flower that has just opened. As a result, the trumpet has just barely started to show its pink hue.



Transcribed by Potter. I'll add the photos at a later date, when I'm not tired.