Magnoliids

 

Archaic Dicotyledon tree-like or herbaceous, pinnate venation. Pollen monoaperturate.

 

 

Order

Species Number

Basal family

Magnoliids

Magnoliales

2929

Basal family

Magnoliids

Laurales

2858

Basal family

Magnoliids

Canellales

2509

Basal family

Magnoliids

Piperales

4090

Key to the main orders

(Spichiger, R. et al. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions, 2004)

1. Herbaceous plants with leaves often having parallel venation and flowers with a single whorl of perianth. .....Piperales

1. Trees or bushes often fragrant, with trimerous, flowers with tepals or with a single whorl of perianth.

2. Flowers hypogynous, stamens with longitudinal dehiscence. ...Magnoliales

2. Flowers perigynous, stamens with valvular dehiscence. ....Laurales

Bennetitales and Gnetum

Bennetidales are an extinct group of gymnosperms (Triassic to Cretaceous) with hermaphrodite (bisporangiate or bisexual), often compound reproductive structures in which the pedunculate ovules, surrounded by interseminal scales, formed a globose cone, which was surrounded by microsporophylls. This assemblage was in turn often subtended by spirally arranged bracts and the whole compound structure was placed axillary to a subtending pinnate or compound leaf, often broken off and only leaving a leaf scar. Stems were short, unbranched and squat, or slender and branched in other groups. The leaves often resembled those of cycads, but the two groups are not closely related. Botanists have long looked at the Bennetitales for possible ancestors of angiosperms due to their hermaphrodite ‘flowers’ and there may indeed be a phylogenetic relationship that is closer than with other groups so far discovered (Crane, Friis & Pedersen, 1995).

Bennetidales: Diagrammatic reconstruction of the bisporangiate, or bisexual, strobilus of Williamsoniella coronata from the Jurassic (Raven, P. et al ' Biology of Plants' 6th ed. 2003. p473)

Gnetum forms mostly lianas, sometimes shrubs or small trees, and has opposite, petiolate, large and broad leaves with pinnate-reticulate venation much resembling dicotyledonous angiosperm leaves. These traits are most likely due to convergent evolution. Of several ovules in the initially compound female ‘cone’ only one large seed develops. Gnetum is exclusively tropical and occurs in forests.

Phylogenetic relationships are uncertain, with most of the molecular evidence supporting a relationship with conifers and the morphological evidence indicating a relationship as sister group to angiosperms. They probably are not closely related to either.

Gnetaceae. A.Gnetum indicum, fruiting branch. B-E Gnetum africanum. B Male spikes. C Part of male spike. D Male flower. E. Fruiting spike. F, G Gnetum latifolium. F. Male flower. G. Male spikes. H-L Gnetum gnemon. H Female spike with rudimentary male flowers. I Female flower. J Female spike. K Seed. L Seed in longitudinal section (A. from Foster and Gifford 1959; B-E from Engler 1908; F-G from Wettstein 1935; H from Bold et al. 1980; I,K,L from Velenovsky 1910; J, from Markgraf 1926.

Welwitschiaceae. Welwitschia mirabilis. A Habit. B Male cone. C Male flower. D Female cone. E Female flower. F Young fruit (A,D,F from Le Maout and Decaisne 1876; B,C,E from Engler's Syllabus 1954)

Recap

Extreme reduction of the life cycle. The sporophyte becomes dominant. Megaspores and microspores are not released but instead develop as megasporophyte and microsporophyte within the sporophyte. The microsporophyte is the pollen grain that will be wind dispersed. The megasporophyte develops within the ovule. The ovule will develop in an embryo that will be become and independant young sporophyte or seed able to stop its metabolism and grow when good conditions are found.

Angiosperm Life cycle (Modified from Singer 1997.

Angiosperms

  1. Megasporangia within an ovule and ovule within a carpel with a stigmatic surface for pollen germination. (Seed in a box). The carpel corespond to the megasporophyll.
  2. Megasporangia and Microsporangia grouped within the same structure or flower. (Flowering plant).
  3. Flower with whorl of perianth usually sepals and petals
  4. Wood with vessels.
  5. Double fertilization. ovule (embro 2n) and endosperm (albumen 3n)
  6. Microsporangia or pollen formed in a stamen with a filament and an anther containing two theacea and 4 pollen sacs joined by a connective tissue.

Changes in diversity at the species level, of suprageneric taxa in the Cretaceous and Tertiary Eras (Niklas, Tiffney & Knoll 1985)

Carpel evolution

Winteraceae and Degeneriaceae present a very primituve carpel morphology where the stigmatic surface id not completely closed.

Transformation of the Carpel into a close carpel in Degeneriaceae and Winteraceae

flower
stamens
stigmatic surface
carpel section
Drymis winteri in Tierra del Fuego Argentina (Ushuaia Nat. Park) and Pseudowintera colorata in New Zealand Banks Peninsula Hinewai Reserve
Drymis winteri Drymis winteri
Pseudowintera colorata
Pseudowintera colorata

 

Amborella

Amborella trichopoda is considered to be one of the most primitive flowering plants surviving today . A shrub whose wood lacks the vessels characteristic of most flowering plants, it is a relic restricted to the under story in wet forests of upland New Caledonia. Amborella has separate male and female individuals, and the female plants in the wild produce large numbers of single-seeded red fruit. Source http://www.ucalgary.ca/~laidlaw/

female flowers
female flowers with a few 'sterile' stamens
male flowers

 

 

 

 

 

 

Plates

Magnoliales

Magnoliales: Magnoliaceae (Spichiger, R. et al. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions, 2004)

Trees or shrubs.

Stipules caducous.

many tepals, stamens and carpels large, spiral and free. Actinomorphic and hypogynous.

Stamens lamellar

Fruits follicles with dorsal dehiscence forming a syncarp

Seeds fixed on a long pendant funiculus.

 

Since the discovery of a fossil structure of Bennettitales resembling a large strobiloid flower most systematists supported the hypothesis of a large primitive flower of the Magnolia type, i.e., the magnoliidian euanth theory.

Laurales

Laurales: Lauraceae (Spichiger, R. et al. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions, 2004)

Trees with fragrant leaves and bark.

Leaves entire.

Flowers with 6 tepals, 3-9-12 stamens and 1 carpel. Flowers sometimes with a hypanthium.

Anthers with two or four valves. Filaments often with nectariferous basal appendages.

Fruit a drupe often surrounded by a cupule (enlarged hypanthium)

Madeira Lauraceae forest
Laurissilva
Laurissilva
Apollonias barbujana
Apollonias barbujana
Laurus azorica
Laurus azorica
Ocotea foetens
Ocotea foetens

 

Piperales

Piperales: Piperaceae (Spichiger, R. et al. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions, 2004)

Herbs, shrubs, stem with sympodial growth, thickened at nodes.

Leaves with parallel venation.

Inflorescence a dense spike on a more or less fleshy axis.

Flowers without perianth, 1-10 stamens and 1-4 carpels, bisexual or unisexual.

Fruit berry or drupe.

Macropiper in New Zealand
Macropiper excelsum
Macropiper excelsum fruiting spike

 

Piperales: Aristolochiaceae (Spichiger, R. et al. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions, 2004)

Herbs, shrubs or climbers.

Flowers with 3 sepals fused in a tube, 4-6-12 stamens and 4-6 carpels fused and ovary inferior. Petals absent except in Saruma.

Stamens free or united to the style and thus forming a column.

Fruit a capsule opening in the formof an umbrella.

 

 

Saururaceae

The angiosperm archetype: they evolved by complication, i.e., by the transformation of bracts into coloured perianth and by the transformation of the small flowers into stamens and carpels, to give the ultimately a hermaphrodite flower. This is the pseudanth theory, i.e. of the primitive inflorescence.

Saururaceae plate source The families of flowering Plants L. Watson and M. J. Dallwitz

Saururaceae pictures
Anemopsis californica Anemopsis californica
Saururus cernuus
Saururus cernuus

Bibliography

Judd, W.S.; Campbell, C.S.; Kellogg, E.A.; Stevens, P.F. 1999. 'Plants systematics, a phylogentic approach' Sinauer Associates Inc. Publ. , Sunderland, 464p.

Heywood, V.H. 1985 'Flowering Plants of the World' Equinox publ., Oxford, 336p.

Spichiger, R.; Savolainen, V.; Perret, M.; Figeat, M. 'Systematic Botany of Flowering Plants: A New Phylogenetic Approach to Angiosperms of the Temperate and Tropical Regions Published by Science Publishers, 2004

Home page

Key to the main orders

Bennetitales and Gnetum

Recap

Angiosperms

Carpel evolution

Amborella

Plates

Saururaceae

Bibliography

Practical

Magnoliales

Laurales

Piperales

 

     

Magnoliales

 

Order

Family

Species Number

Magnoliids

Magnoliales

Myristicaceae

475

Magnoliids

Magnoliales

Magnoliaceae

227

Magnoliids

Magnoliales

Degeneriaceae

2

Magnoliids

Magnoliales

Himantandraceae

2

Magnoliids

Magnoliales

Eupomatiaceae

3

Magnoliids

Magnoliales

Annonaceae

2220

MAGNOLIACEAE Magnolia stellata (Siebold & Zucc.) Maxim.

Range: Japan

Questions: Explain the Euanth theory.

Large flower with many tepals, single carpels and stamens spirally arranged.

Observe the individual carpels and stamens. Why are they 'primitive'

They are free with short style, the stamens have short undiferenciated filaments and a long connective.

Floral Formula:

P*A* G*Vm1-2
gynoecium section of the gynoecium
flower androecium stamens
Floral diagram section of a carpel stamen

Laurales

 

Order

Family

Species Number

Magnoliids

Laurales

Atherospermataceae

16

Magnoliids

Laurales

Calycanthaceae

11

Magnoliids

Laurales

Gomortegaceae

1

Magnoliids

Laurales

Hernandiaceae

55

Magnoliids

Laurales

Lauraceae

2500

Magnoliids

Laurales

Monimiaceae

200

Magnoliids

Laurales

Siparunaceae

75


LAURACEAE Litsea cubeba

Collected by: Expd.to Sichuan (SICH) no. 326
Field notes: Sichuan, returning from Campsite 1 to Moshi town, Gongga Shan. Steep hillside, south facing, mixed broadleaves of small trees and shrubs, damp habitat. Shapely young tree to 8m. Open habitat, leaf to 9cm. long 3cm. wide, berries black 3mm. in diameter, Alt.1770m. Coll. 1.10.88.

Questions: Is this plant dioecious or monoecious ?

Dioecious.

What is the most diagnostic character you can see ?

The anthers opening with 4 valves.

Describe the androecium.

2 whorls, one with 5 stamens the other with 3 and with nectariferous appendages at the base of the filaments.

Floral Formula

♂ P6* A6+3* G1r
Flowering branch flower dissection Outer stamen Inner stamen
Floral diagram flower

Piperales

 

Order

Family

Species Number

Magnoliids

Piperales

Aristolochiaceae

480

Magnoliids

Piperales

Hydnoraceae

7

Magnoliids

Piperales

Saururaceae

6

Magnoliids

Piperales

Piperaceae

2000

1
ARISTOLOCHIACEAE Isotrema manchuriensis H.Huber
Synonyms: Aristolochia manshuriensis Kom.

Collected by: Kirkham, Flanagan & Boyce Expd.to Korea. (KFBX) no. 28 on 28/09/1989
Geography: South Korea Findspot: Kangwon Prov., Inje borough. Sorak-san National Park, track to Paekdamsa Temple,
Altitude: 440 metres
Field notes: Deciduous woody perennial. Common. Vigorous climbing species occurring throughout mixed deciduous woodland.

Questions: How does it differ from Aristolochia ?

Aristolochia or Isotrema differs from Aristolochia because the calyx tube is lobed at the apex.

What are the 'advanced or derived characters' in this plant ?

Fused carpels, inferior ovary, the column and fused calyx.

How many fused carpels can you see on the ovary cross section ?

6

Floral Formula:

K(3)↓ C0 [A6* Ĝ(6)↓Vx]
Column and calyx mouth
longitudinal section of the calyx tube cross section of the ovary
Flower Floral diagram

 


PIPERACEAE Peperomia prostrata B.S.Williams

Questions: What type of inflorescence ?

a dense fleshy spike.

Identify the perianth ?

Floral Formula:

K0 C0 A2* G1*Vb1
single flower

Floral diagram

Inflorescence flowers
bract, ovary and stamens adaxial and abaxial leaf surface Leaf section

 

 

Practical

Magnoliales

Laurales

Piperales