1. DEPARTMENT OF LIFE SCIENCES
SRINIVAS S. SURYAVANSHI
M.Sc 2nd plant sciences
Roll no. – 2019MLS10
2. Gentianales
Gentianales is an order of flowering plants,
included within the asterid clade of eudicots. It
comprises more than 16,000 species in about
1,138 genera in 5 families. More than 80% of
the species in this order belong to the
family Rubiaceae.
Gentiana cruciata
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Clade: Lamiids
Order: Gentianales
Juss. ex Bercht. & J.
Presl
Families
•Apocynaceae
•Gelsemiaceae
•Gentianaceae
•Loganiaceae
•Rubiaceae
•Family Apocynaceae (424 genera)
•Family Gelsemiaceae (2 genera)
•Family Gentianaceae (87 genera)
•Family Loganiaceae (13 genera)
•Family Rubiaceae (611 genera )
Gentianales
3. Apocynaceae (Dogbane
family) (Milkweed )
Greek for away From dog – in reference to some
taxa used as dog poison.
Belongs to order Gentianales
includes 400 genera , 4,555 species.
It has 5 subfamilies
Apocynoideae
Asclepiadoideae
Periplocoideae
Rauvolfioideae
Secamonoideae
Catharanthus roseus
Rauvolfia
Calotropis gigantea
6. Vegetative characters
Habit:
Herbs, shrubs, twiners , lianas, with latex.
tall evergreen trees up to 80 m, with buttress
roots, such as Alstonia and Dyera
lianas, such as Landolphia
Asclepias syriaca(common milkweed, butterfly
flower)
Apocynum commonly known as dogbane or Indian
hemp.
Many plants important for medicinal use, some
plants are poisonous ,consisting of alkaloid ,
cardenolides, triterpenoids , and iridoidsApocynum androsaemifolium
Asclepias syriaca
Landolph
Alstoni
7. Roots
Tap roots and branched
Nerium oleander
Stem
Aerial , erect, herbaceous, woody/ climber,
latex in some thorny.
Apocynum cannabinu
m
Alyxia oliviformi
9. Floral characters
Inflorescence : Usually
Cymose either Terminal or
axillary May be corymbose
cymes cyme(Carissa) or
Umbellate Cyme Rauvolfia ,
cymose type Calotropis
gigantea Carissa
RauvolfiaCalotropis gigantea
10. Flower : Bracteate or
Ebracteate , Pedicellate,
complete, hermaphrodite,
Actinomorphic, Tetra or
pentamerous, often with Corona
Vinca minorVinca roseus
Allamanda cathartica
Apocynaceae
Oleander
11. Calyx : Sepals 5 , gamosepalous ,
polysepalous(vinca) rarely 4,
deeply lobed small often
Glandular at base ,quincuncial
aestivation
Corolla : petals 5
Gamopetalous ,
(oleander)funnel shaped twisted /
valvate , but sometimes
campanulate(Vinca) , carona
like within tube (vinca and
Oleander).
Androecium :5 epipetalous, ,
alternating with petals ,
inserted and filament short ,
introse .
Twisted Imbricate
Apocynaceae
Oleander
12.
13. Gynoecium: 2 , bicarpellary, apocarpous, may be
apically united , superior ovary usually bilocular with
ovules or many ovules .axile /marginal placentation
Fruits :A drupe (Thevetia), berry (Carissa), follicle(
Nerium / Calotropis)
Thevetia Nerium Calotropis
Apocynaceae
Pollination : Entomophily , few ornithophily
(Carissa),
16. Asclepiadaceae
Vegetative characters:
Habit:
shrubs (Calotropis, Leptadenia), succulent (Stapelia) with
latex.
Root:
branched tap root.
Leaves:
,petiolate, exstipulate, entire, opposite rarely whorled,
waxy; in Dischidia rafflesiana leaves are modified into
pitchers,
Floral characters:
Inflorescence:
Mostly umbellate cymes (Calotropis)
Flower:
Bracteate or ebracteate, pedicellate, complete,
hermaphrodite, actinomorphic, pentamerous, hypogynous.
Calyx:
Sepals 5, polysepalous or gamosepalous-fused near the
base, sometimes valvate
Dischidia rafflesiana
17. .
Corolla:
Petals 5, gamopetalous, 5 lobed, twisted aestivation or valvate, corona
hairy out growth from petals i.e. staminal corona in Calotropis .
Androecium:
Stamens 5, synandrous, gynostegium (stamens fused with stigmatic disc to
form gynostegium), epipetalous; the pollen grains of each half anther usually
agglutinated into granular mass of tetrads or waxy pollen called pollinium
(Asclepias, Calotropis). Thus each stamen has two pollinia.
.
Gynoecium: Bicarpellary, syncarpous, ovaries free, superior, ovules many
on marginal placentation, carpel is unilocular; stigmas united to form a
pentangular disc with which anthers are fused to form gynostegium.
Fruit: follicles.
Seed:Many small, compressed with long silky hairs
.
Pollination: Entomophilous.
Floral formula:
18. Economic importance of Apocynanceae :
1. Vegetables:
fruits of Carissa carandus (H. Karaunda) are edible
2. Medicinal:
The root of Rauwolfia serpentina (H. Sarpgandha) are used in lowering
blood pressure, sedative, stimulator for uterine contraction and in mental
diseases. The juice of leaves is used for removal of opacities of the cornea of
the eyes. Anti-cancerous drugs are extracted from Catharanthus roseus.
Holarrhena antidysentrica yields a drug which is a cure for amoebic
dysentery.
3. Rubber:
Many species of Hancora, Dyera, Urceola are the sources of rubber.
4. Poisonous:
The seeds of Thevetia contain Thevetine a poisonous glycoside. The latex of
Acokanthera is used for poisoning arrows. The bark and wood of Nerium
indicum provide rat-poison.
5. Ornamental:
Nerium, Catharanthus (syn. Vinca), Thevetia, Wrightia, Allamanda are
cultivated in gardens as ornamentals.
Carissa carandus
Rauwolfia serpentina
