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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 

Morphology of gentians Voyria

Gentians are very variable in their morphology. Listed below are some traits that occur in the family and their occurrence in some genera. Bibliographic references are listed in parenthesis [ ] after the characters. More information on most of these characters are available in Struwe et al. (2002).

See anatomy page for Anatomy, Palynology, Embryology, and Chemistry characters.

Habit (growth habit, trophy)

Roots, hairs, stems 

Leaves (petioles, stipules) 

Inflorescence (branching, position, bracts)

Flowers (see also Flower anatomy)

Calyx (sepals; see also Flower anatomy)

Corolla (petals; see also Flower anatomy)

Glands in the flower (see also Flower anatomy)

Stamens (androecium, filaments, anthers; see also Flower anatomy)

Gynoecium (pistil, ovary, style, stigma; see also Flower anatomy)

Fruits (see also Flower anatomy)

Seeds (see also Embryology)

Habit (growth habit, trophy):

 

trees: e.g., Anthocleista, Chorisepalum, Fagraea, Macrocarpaea, Potalia, Prepusa, Symbolanthus

 

shrubs: e.g., Adenolisianthus, Chorisepalum, Gentianothamnus, Fagraea, Ixanthus, Macrocarpaea, Orphium, Potalia, Prepusa, Saccifolium, Symbolanthus, Tachia

 

woody lianas and climbers: e.g., Anthocleista spp., Lagenanthus, Purdieanthus

herbaceous climbers: e.g., Bisgoeppertia, Crawfurdia

 

herbs: most gentians

 

single-stemmed trees and shrubs (monocarpic): Potalia

 

candelabra-shaped branching: Anthocleista spp.

 

leaves crowded at branch apices: many in subtribe Potaliinae and tribe Helieae

 

autotrophic plants: most gentians

Voyria

heterotrophic plants, mycotrophs, saprophytes: Bartonia (partly heterotrophic), Cotylanthera, Obolaria (partly heterotrophic), Sebaea oligantha, Voyria, Voyriella

Veratrilla

dioecious plants (male and female flowers on separate plants): Gentianella spp., Veratrilla. All other gentians have flowers that have fully functional male (stamens) and female (gynoecium) parts in the same flower.

 

prostrate habit (horizontal branching on the ground, rooting at the nodes): Exacum spp.

 

Roots, hairs, stems:

 

taproots: most gentians

 

coralloid roots, bird's nest roots (associated with mycorrhiza): Obolaria, Voyria, Voyriella

 

glabrous plants (lacking hairs): most gentians

 

hairy plants: Chironia spp., Macrocarpaea spp., Microrphium, Ornichia, Orphium

 

glandular hairs:

glaucous plants (with a waxy, bluegreen surface layer): Blackstonia, Eustoma

 

viscid plants (sticky): Ixanthus

 

bristles on vegetative parts (hard, sharp hairs): Microrphium, Orphium

 

corky bark: Saccifolium

 

hollow stems: common

 

terete (round) stems: common

 

quadrangular (4-cornered) stems: common

winged stems: common

 

Leaves (petioles, stipules):  

opposite leaves (leaves 2 and 2 along stem): nearly all gentians

 

alternate leaves (leaves single along stem): Saccifolium, Voyriella spp.

 

whorled leaves (verticillate, 3 or more together along stem): Curtia spp., Exacum spp.

 

leaves in basal rosette (rosulate): many gentians, especially in Chironieae and Gentianeae, e.g., Centaurium spp., Gentianella spp.

amplexicaul/perfoliate leaves (opposite leaves that are fused together at their bases): Exacum spp., Prepusa spp., Symphyllophyton, Tachiadenus spp.

 

saccate leaves (sack-shaped): Saccifolium

 

entire leaves (margin smooth, not lobed or dissected): all gentians (except Irlbachia poeppigii and some Fagraea)

 

dentate leaves (margin with teeth): Fagraea spp., Irlbachia poeppigii

 

scale-like leaves (leaves very small, like scales): Bartonia, Cotylanthera, Sebaea oligantha, Voyria, and Voyriella

 

interpetiolar line (ridge between the base of a pair of leaves): most gentians

 

interpetiolar stipules (a flap of leaf-like tisse between a pair of leaves): Macrocarpaea spp., very rare in the family, only occurs in one species

 

interpetiolar sheath ( a ring of tissue around the stem at the base of a pair of leaves): Anthocleista, Chorisepalum, Fagraea, Lisianthius, Macrocarpaea, Potalia 

 

auricules at base of leaves (ear-shaped appendages at the base of a leaf): Anthocleista spp., Fagraea spp.

 

axillary spines (spines in the leaf axil): Anthocleista

acrodromous leaf venation (arcuate, few veins, bent towards apex of leaf): common

 

brochidromous leaf venation (pinnate, veins straight towards edge of leaf): common in some genera, e.g., Anthocleista, Macrocarpaea spp., Fagraea

 

Inflorescence (branching, position, bracts):

axillary inflorescences (in leaf axils): many gentians, e.g.,  Enicostema, Saccifolium, Tachia, Zonanthus

terminal inflorescences (at top of branch): many gentians

 

solitary flowers (flowers one by one, not together): Cotylanthera, Gentianothamnus, Saccifolium

cymes (a type of inflorescence with a top flower and side branches that repetitive branch sideways, symmetrically or assymmetrically): most gentians

 

racemes: Fagraea spp.

 

capitate (flowers in tight heads): Cracosna, Tapeinostemon spp.

Coutoubea

spicate (flowers in a spike): Coutoubea

 

cymes with monochasial branches (branches that only branch on one side, giving the appearance of one long branch with many flowers on one side): Chelonanthus, Irlbachia, Symbolanthus

Tachia

flowers sessile (flowers without flower stalk, sitting directly on stem): Tachia, Tapeinostemon sessiliflorum, many in subtribe Faroinae

 

bracts and bracteoles scale-like, small (bracts are the small leaves in the inflorescence, often occur in pairs): most gentians

 

bracts leaf-like: Macrocarpaea

 

bracts perfoliate (a pair of bracts that are fused together at their base) : Ixanthus

 

extra bracts (more than 2) below flower or inflorescence: Fagraea spp.

 

 

Flowers (see also Flower anatomy):

 

3-merous flowers (3 calyx lobes, 3 corolla lobes, 3 stamens): Pycnosphaera (rarely in Enicostema)

Cotylanthera

4-merous flowers: many gentians, e.g., Canscora, Centaurium spp., Cicendia, Congolanthus, Coutoubea, Cracosna, Djaloniella, Exaculum, Faroa, Geniostemon, Hoppea, Ixanthus [also 5-merous], Karina, Neurotheca, Oreonesion, Sabatia spp., Schinziella (rarely in Enicostema)

Macrocarpaea

5-merous flowers: most gentians

Prepusa

6-merous corolla: Chorisepalum, Blackstonia spp., Prepusa, Senaea (occasionally 6-7 also in some other genera: Enicostema, Gentiana, Irlbachia).

Anthocleista

8-16-merous corolla and stamens: Anthocleista (10-16), Blackstonia (6-12), Potalia (8-10), Sabatia (4-5, 8-13), Urogentias (8)

 

2 sepals, 4 petals, 4 stamens: Cracosna, Obolaria

 

2 sepal lobes, 5 petals, 5 stamens: Microrphium

 

3 sepals, 4 petals, 4 stamens: Cracosna

 

4 sepals, 6 petals, 6 stamens: Chorisepalum

Anthocleista

4 sepals, 8-16 petals, 8-16 stamens: Anthocleista, Potalia

hypogynous (ovary superior): all gentians

Veratrilla

unisexual flowers: Veratrilla and Gentianella spp.

 

heterostylous flowers: only in tribe Saccifolieae, e.g., Curtia, Hockinia, Tapeinostemon spp., Voyriella [Knoblauch, 1895]

 

cleistogamous: Sebaea oligantha only

actinomorphic (radially symmetric) flowers: most gentians

Symbolanthus zygomorphic (bilaterally symmetric) flowers: see zygomorphy under calyx, corolla, and stamens below
Gentiana erect flowers (upright on the plant): many gentians
horizontal flowers (sideways): many gentians
Crawfurdia

nodding flowers (hanging down): Crawfurdia, Lagenanthus, Lehmanniella, Lisianthius, Purdieanthus

 

Calyx (sepals; see also Flower anatomy):

fused sepals (at least at base of calyx): most gentians

 

free sepals: Anthocleista, Chorisepalum, Potalia

 

actinomorphic (symmetrical) calyx: most gentians

 

zygomorphic (bilateral) calyx: Exacum spp., Frasera

wing (lower picture) or keel (upper picture) on back of sepals: Canscora spp., Cicendia, Exacum spp., Schultesia spp., Symbolanthus spp., Tachia spp., Tachiadenus spp.
Wings are very thin; keels are thicker at the base.

dorsally thickened sepals: many in tribe Helieae, many also have wings or keels

Prepusa

membranaceous sepals (paper-thin): Prepusa

 

sepals deciduous (fall off) in fruiting stage: Chorisepalum, Macrocarpaea, Tachia

Potalia

yellow-orange calyx: Potalia

 

imbricate calyx lobes in bud: common

 

decussate calyx lobes in bud: Anthocleista, Chorisepalum, Potalia

 

membrane between calyx lobes (intracalycine membrane: Crawfurdia spp., Gentiana spp.

 

Corolla (petals; see also Flower anatomy):

Crawfurdia

fused petals (sympetaly): all gentians  are at least fused at the very base of the petals

Lisianthius

actinomorphic corollas (symmetric, all lobes equal): most gentians

Symbolanthus

slightly zygomorphic corollas (not symmetric, lobes unequal) : e.g., Canscora spp., Chelonanthus spp., Symbolanthus spp.

rotate corollas (deeply divided, only fused at base, lobes spreading widely): e.g., Frasera, Swertia

Tapeinostemon

tubular corollas (straight tube, lobes straight): e.g., Potalia spp.

salvershaped corollas (like a trumpet, narrow tube and flaring lobes): e.g., Lisianthius spp., Symbolanthus spp., Tachia spp., Tachiadenus

Tetrapollinia

funnelshaped corollas (like a funnel, narrow tube and lobes spreading, but not flaring): e.g., Chelonanthus, Gentianothamnus, Symbolanthus spp., Tetrapollinia

Crawfurdia

bellshaped corollas (campanulate):

Gentiana tubular corollas that never open: Gentiana spp. (bottle gentians) are forced open by bumblebees for pollination, the flowers never open by themselves (see Pollination)
Eustoma

contort corolla lobes in bud (all lobes twisted and overlapping in bud): most gentians

 

imbricate corolla lobes in bud (lobes overlapping except two, one inner and one outer): Bartonia, Obolaria, Saccifolium only

 

valvate+contort corolla lobes in bud (valvate = lobes not overlapping, only sitting edge to edge): Aripuana only

petal edges erose (papillate): common in many genera

petal edges ciliate or dentate (with hairs or teeth along edge): Gentianopsis, Pterygocalyx

Comastoma

fimbriae (hairs) at the base of the corolla lobes: Comastoma, Gentiana, Gentianella spp.

Tripterospermum

folds (plicae) between corolla lobes (thinner folded tissue fusing corolla lobes): Crawfurdia, Gentiana spp., Metagentiana, Tripterospermum

Halenia

each petal with a spur (a thin, long and hollow structure attached to a petal): Halenia only

Enicostema

white petals: e.g., Anthocleista, Coutoubea, Enicostema, Irlbachia spp., Fagraea spp., Saccifolium, Symbolanthus spp., Tachiadenus spp.

Blackstonia

yellow petals: e.g., Blackstonia spp., Ixanthus spp., Sebaea spp., 

Lagenanthus

orange petals: e.g., Lagenanthus spp., Tapeinostemon spp., 

Gentianella

red petals: e.g., Gentianella spp., Rogersonanthus spp., Symbolanthus spp.

Centaurium

pink petals: e.g., Centaurium spp., Sabatia, Symbolanthus spp.

Halenia

purple petals: e.g., Anthocleista spp., Chelonanthus spp., Exacum spp., Gentianella spp., Halenia spp.

Gentiana

blue petals: e.g., Exacum spp., Gentiana spp.

 

black petals: Lisianthius nigrescens

Macrocarpaea

green petals: e.g., Chelonanthus spp., Macrocarpaea spp., Potalia spp.

petals with nectar guides (stripes inside corolla mouth and/or on lobes): Symbolanthus spp.

Corolla with darker lobe apices: some Helieae
 

corolla with lighter-colored 'eye' in middle of flower: Eustoma, Sabatia

 

corolla persistent in fruit (does not fall off when fruits develop): many Gentianeae and Chironieae

 

Glands in the flower (see also Flower anatomy):

 

colleters (small, finger-shaped glands on inside of sepals): common in many gentians and other families of the Gentianales

 

colleters absent from calyx: e.g., Bisgoeppertia, Coutoubea, Cracosna, Eustoma

 

glandular ridge on back of sepals: common in Helieae

nectaries on inside of corolla tube or on lobes: Frasera spp., Gentianella spp., Swertia spp., 

 

nectary disk at base of ovary: many in tribes Potalieae and Helieae, a few in subtribe Gentianinae, e.g., Gentianothamnus, Tripterospermum

 

glands at apex of anther: Sebaea spp.

 

glands at base of anther: Sebaea spp.

 

Stamens (androecium, filaments, anthers; see also Flower anatomy):

 

stamens fewer than corolla lobes: Canscora spp., Hoppea, Schinziella

 

stamens alternating with corolla lobes: all gentians

stamens inserted in the corolla tube: most gentians

 

stamens inserted in the corolla lobe sinuses: e.g., Aripuana, Djaloniella, Faroa, Geniostemon, Sabatia, Swertia spp.

 

actinomorphic stamens (symmetric): most gentians

Exacum

zygomorphic stamens (assymmetric) : e.g., Calolisianthus, Chelonanthus, Cotylanthera, Exacum spp., Orphium, and Symbolanthus

 

anisomorphic stamens (stamens of different shapes and sizes): Canscora, Hoppea, Schinziella

 

corona at the base of stamens (ring of tissue): Symbolanthus only

 

appendages at base of stamens (flaps, hoods, wings): common in subtribe Faroinae and Coutoubea

 

flattened filaments: many in tribe Saccifolieae

 

curved filaments: Gentiana sect. Stenogyne and Tripterospermum

 

winged filaments: Gentiana spp.

 

apically recurved filaments (filament strongly turned close to the anther): many in tribe Helieae

 

fused (partially or completely) filaments: Anthocleista, Potalia

 

fused (connate) anthers: Gentiana spp., Sebaea spp., Tachiadenus spp. [Duncan & Brown, 1954]

 

long, linear anthers: e.g., Anthocleista, Deianira, Fagraea spp., Potalia, and many in tribe Helieae

Symbolanthus

recurved (bent) anthers: many in tribe Helieae, e.g., ChelonanthusSymbolanthus

spirally twisted/coiled anthers: many in subtribe Chironiinae, e.g., Centaurium, Chironia, Orphium, Sabatia, Canscora

 

twisted backwards anthers: Sebaea spp.

 

longitudinally dehiscent anthers  (with slits): most gentians

sagittate anthers (V-shaped, split at base): many gentians [photo shows anther upside down]
 

poricidal anthers (pores at apex): Cotylanthera (1 pore), Exacum spp. (2 pores)

 

introrse anthers (open toward the middle of flower, on the inside of the anther): most gentians

 

latrorse anthers (open toward the sides of the anthers): Voyriella spp., Saccifolium

 

anthers with apical appendages (with extra tissue on the tip of the anther): many in tribes Exaceae, Helieae, and Saccifolieae

 

anthers with basal appendages: some in tribe Exaceae

 

coriaceous anthers (leathery, thick anthers): Exacum, Gentianothamnus

 

Gynoecium (pistil, ovary, style, stigma; see also Flower anatomy and Fruits, below) [Gopal Krishna & Puri, 1962]:

 

bicarpellate gynoecium (formed from 2 fused carpels): all gentians

 

syncarpous gynoecium: all gentians

 

stipitate gynoecium (on gynophore): many in tribe Gentianeae

 

sessile gynoecium: most gentians

Tachia

style long, filiform, distinct: many in tribes Exaceae, Helieae, Potalieae

 

style twisted when dry: many Helieae

Exacum

style zygomorphic: many in tribe Exaceae and Helieae

 

style short or absent: many in tribe Gentianeae

 

decurrent stigma along carpel sutures: Bartonia, Lomatogonium spp.

 

with additional lower stigma: Sebaea spp. [Marloth, 1909]

Tachia

strongly bilamellate (bilobed) stigma: many Helieae, Fagraea spp., Centaurium, Eustoma

capitate stigma: common, e.g., Lisianthius, Potalia

 

simple stigma: common in tribe Exaceae

 

peltate stigma: Voyria spp.

long, coiling stigmatic lobes: Sabatia

 

Fruits (see also Flower anatomy and Gynoecium, above):

capsules, dry and thin: most gentians

 

capsules, leathery: Symbolanthus

 

capsules, woody: Chorisepalum, Tachia

berries: Anthocleista, Chironia baccifera, Fagraea, Potalia, Tripterospermum spp.

(many different colors)

 

apical, septicidal dehiscence (opens from top along sutures): most gentians with capsules

 

apical dehiscence, with coriaceous lid: Exacum spp.

medial dehiscence (opens in the middle): some Helieae, Voyria spp.

 

capsule splits into 4 valves: Macrocarpaea spp., Chorisepalum

 

indehiscent fruits (never opens): Symbolanthus spp.?, Voyria spp.?, and the genera with berries

 

parietal placentation (placenta attached to fruit wall): many gentians (this character is very plastic and both parietal and axile placentation can be found within the same gynoecium/fruit in some species)

 

axile placentation (placenta attached to fruit center), at least for 1/2 of the length of the fruit: many in tribe Exaceae, some in Helieae

 

intruding placentas (placenta large and intruding far into the fruit from the walls and/or center): common in many gentians, especially in tribe Helieae, e.g., Anthocleista, Centaurium, Fagraea, Gentianothamnus, Tachiadenus

 

seeds distributed over entire inner wall of fruit: many in subtribe Swertiinae

 

 

Seeds (see also Embryology; [Bouman et al., 2002; Grothe & Maas, 1984]): 

 

numerous seeds: most gentians

 

round or oblong seeds: Tachia spp., Tachiadenus spp., Voyria spp.

 

flattened seeds: many in tribe Gentianeae, in subtribe Potaliinae, Chorisepalum, Macrocarpaea spp.

 

cup-shaped seeds: Exacum spp., Voyria spp.

 

winged seeds: some in tribe Gentianeae, Chorisepalum, Macrocarpaea spp.

 

angular seeds: common in tribes Exaceae and Helieae

 

filiform seeds: Voyria spp.

 

dust seeds (very small): Voyria

 

aril: absent in all gentians

 

aborted seeds, filiform: Voyria spp.

 

spp. = some species, this indicates that some but not all investigated species in the genus has this character

e.g.= for example

 

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