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This page is maintained 
by Dr. Lena Struwe 
(e-mail), and hosted by
Rutgers University
, USA

Credits

updated: 01/19/11 

Gentianaceae
- how do they look like?
Macrocarpaea

The gentian family contains about 87 genera and over 1600 species.  The family is classified in the angiosperm order Gentianales, and belongs to the Asterid I clade and the subclass Asteridae.  What is a gentian?

Typical characteristics for gentians are:

- plants glabrous (no simple or glandular hairs)

- opposite, simple, entire leaves

- leaf venation with a prominent midrib and few, basally divergent and curved secondary veins

- no stipules (but sometimes with an interpetiolar line or a low, interpetiolar sheath)
flowers actinomorphic (radially symmetric, rarely not)

- flowers bisexual (with both stamens and pistil in each flower)

- sepals fused at least at the base  

- petals fused at least at the base (sympetalous)

- petals often very colorful and large

- petal lobes contorted (twisted) to the right in bud

- stamens inserted in the corolla tube (if you pull a stamen off, the petals come too)

- ovary superior (hypogynous flowers)

- ovary bicarpellate (the pistil is formed by two carpels)

- chemicals present: seco-iridoids and xanthones (alkaloids are absent)

(more about gentians' morphology and anatomy)

 

 

How to distinguish a gentian (Gentianaceae) using field characters from other similar and related plant families:
(Note that there are some exceptions to these 'rules')

 

from Apocynaceae (and Asclepiadaceae, now included in Apocynaceae): gentians lack (vs. have) latex [milky sap]

from Bignoniaceae, Gesneriaceae, and Scrophulariaceae s. lat.: gentians have as many stamens as petals (vs. fewer stamens than petals), the flowers are actinomorphic [radially symmetric] (vs. often zygomorphic [bilateral]), and the leaves are glabrous (vs. often hairy)

from Gelsemiaceae: gentians have homostylous (vs. heterostylous) flowers, simple or bilobed stigmas (vs. 4-branched stigmas/styles) 

from Loganiaceae: gentians have petals lobes contort in bud (vs. valvate or imbricate [irregularly overlapping or not overlapping]), no hairs (vs. with) on the inside of the corollas

from Rubiaceae: gentians have superior (vs. inferior [inserted in the flower stalk below the flower]) ovaries and no (vs. with) interpetiolar stipules

from Solanaceae: gentians have opposite (vs. alternate) leaves

Lena Struwe, 2002 

 

Gentian Research Network, 2002-2011.
For corrections and additions, contact Lena Struwe at struwe@aesop.rutgers.edu