Exams

seed of Claytonia perfoliata  

2012 SYSTEMATIC BOTANY THEORETICAL EXAMINATION

ANSWER SIX QUESTIONS ONLY; USE LABELLED SKETCHES IF NEEDED
TIME ALLOWED 2 HOURS
ALL QUESTIONS CARRY EQUAL MARKS

1.  Find below plate 1with line drawings illustrating morphological characters of Acaena novae-zealandiae.

a) Complete the missing captions A to I with the words or phrases:

  • Achene. A
  • Flower view with spread petals. G
  • Fruiting cupule. K
  • Ovary longitudinal section. F
  • Stigma. E
  • Stamens. B
  • Branch with flowering heads. D
  • Longitudinal section of the flower. H
  • Seed. J
  • Flower in side view. C
  • Spine barbed apex. I

b) List the morphology of the flowers of this family: Number of sepals, petals, carpels, stamens, degree of fusion and position.

(K4 C4 A2) G1
hypanthium conspicuous and cupular, flower perigynous
.

c) This plate illustrates the genus Acaena in the Rosaceae family, give the subfamily this plate belongs to and describe the fruit.

Subfamily Rosoideae. The fruit is a simple fruit, an achene enclosed in an accrescent hypanthium (pometum) which bears barbed spine on the outside.

 Plate 1. Acaena novae-zealandiae. (Cheeseman, T.F. 1914. Illustrations of the New Zealand Flora. Vol. 1. Pl. 39.)

2.  Find below plate 2 a reproduction of the Angiosperm Phylogeny Group phylogenetic tree. (The Angiosperm Phylogeny Group. 1998 An Ordinal Classification for the Families of Flowering Plants.  Annals of the Missouri Botanical Garden. )

a) Assign an APG classification clade and order to the four species listed below (each belonging to a different family):

 

  1. Lunaria rediviva (Cruciferae):euanthial, entomophilous, hypogynous, dialypetalous, gamocarpous, 4-merous flower, ovary of two fused carpels in parietal placentation, tetradidynamous free stamens. Brassicales
  1. Betula pendula (Betulaceae): pseudanthial, wind pollination, epigynous, reduced perianth with one whorl, gamocarpous, perianth reduced, ovary unilocular of two fused carpels, 2 free stamens with bifid anthers. Fagales
  1. Ramonda nathaliae (Gesneriaceae): euanthial, entomophilous, hypogynous, gamopetalous, gamocarpous, 5-merous flower, ovary of two fused carpels in parietal placentation, didynamous epipetalous stamens with connivent anthers. Lamiales
  2. Jasione montana (Campanulaceae): pseudanthial, entomophilous, epigynous, gamopetalous, gamocarpous, 5-merous flower, ovary of two fused carpels in axile placentation, five epipetalous stamens with secondary pollen presentation. Asterales

b) Is it possible to relate the list of simple morphological characters for each species to the APG classification? Briefly discuss.

It is not possible because the number of characters to base our conclusions is too small and could not uncover possible events of convergence, parallelism, hybridisation, reversions…..
It is nevertheless possible to find some more ‘derived’ or advance characters in some ‘higher’ groups like Asterales: Pseudanth, Eentomophilous, Epigynous, Gamopetalous, Gamocarpous, 5-merous flowers, Few carpels, Few stamens and Epipetalous. It is obvious in the table below that every group can have some ‘derived’ characters.

Inflorescence

Pollination syndrome

Flower position

Corolla

Gynoecium

mery

Carpels and placentation

Androecium

Lunaria rediviva

Euanth

entomophilous

hypogynous

dialy petalous

gamo carpous

4

G(2)Vp

tetra didynamous

Betula pendula

Pseudanth

wind pollination

epigynous

0

gamo carpous

0

G(2)Vb

2 free stamens with bifid anthers

Ramonda nathaliae

Euanth

entomophilous

hypogynous

gamo petalous

gamo carpous

5

G(2)Vp

didynamous epipetalous stamens with connivent anthers

Jasione montana

Euanth

entomophilous

epigynous

gamo petalous

gamo carpous

5

G(2)Vx

5 epipetalous stamens with secondary pollen presentation

c) Which other type of data would you add to build a robust classification?

Molecular (DNA) but also anatomy, chemistry and as many available characters as possible.

Plate 2: Phylogenetic tree of the Angiosperms according to the Angiosperms Phylogeny Group (http://www.mobot.org/MOBOT/research/APweb/ - April 2008)

3.  Find below plate 3 with line drawings illustrating morphological characters of Azolla filiculoides(Salviniaceae).

a) Using the illustration as a guide, interpret and explain the reproduction mechanism for this ‘floating water Fern’.  To help the interpretation the massulae are described in the following sentence: The microsporangia break open to release the microspores, which are clumped together with other tissue in massulae that bear barbed hairs called glochidia.

In common with other ferns, Azolla has 2 alternating generations:

  • the main sporophyte plant that produces spores
  • the insignificant gametophyte on which the sexual organs develop

- they produce 2 types of spores, large female spores and tiny male spores. These form inside sporangia contained in sporocarps.

Females:

  • megasporocarps contain 1 megasporangium, inside which a single megaspore develops, as the megaspore matures, floats develop above it, topped with a colony of cyanobacteria and covered by a dark conical indusium; collectively this is known as the ‘megaspore apparatus’; at maturity the megasporangium wall disintegrates to reveal the warty spore wall with its tangled hairs, a female prothallus develops, initially within the megaspore, later protruding, 1 or more archegonia (female sex organs) form on the prothallus

Males:

  • microsporocarps contain numerous microsporangia, each containing many microspores, on maturity the microsporocarp and microsporangia break open to release the microspores, which are clumped together with other tissue in massulae that bear barbed hairs called glochidia, within the massula prothalli develop in the microspores, 1 antheridium (the male sex organ) is produced on the prothallus, The massula glochidia get caught in the hairs of a floating megaspore and the combined structure sinks. Fertilisation occurs and the resulting zygote (fertilised egg) develops into a new sporophyte the following spring.

Azolla species are unique in that the cyanobacterium symbiont is transferred from generation to generation via the megasporocarp, rather than the new sporophyte requiring reinfection by the cyanobacterium.

b) Sketch a simplified life cycle using the words and arrows only (no botanical drawings required): Antheridium, Archegonium, Egg, Embryo, Fertilization, Megagametophyte, Megasporangium, Megaspore, Microgametophyte, Microspanrangium,  Microspores, Sperm, Sporophyte,  Zygote.

 

c) How would you qualify the life cycle of this ‘Fern’ and what advantages could this have?

Azolla is one of the few ferns that are heterosporous. This could be a mechanism that increase the exchange of genetic material between individuals.

Plate 3. Azolla filiculoides floating plant above and sexual reproducing organs below (from Richard Wettstein, Handbuch der Systematischen Botanik (1924)).

 

4.  Find below plates 4 and 5 with line drawings illustrating morphological characters of Dorstenia (Moraceae).

a) Complete plate 4 with the missing captions A to G with the words or phrases:

  • Staminate flowers. B
  • Pistillate flowers. F
  • Peduncle. D
  • Phyllaries. A
  • Inflorescence receptacle. E
  • Pedicels. G
  • Bract. C

b) How would you qualify the Inflorescence of Dorstenia?  Briefly discuss any differences and similarity with the inflorescence found in the Genus Ficus.

This is an example of a head like inflorescence with phyllaries (Pseudanth) and producing a syconium (compound fruit). The fleshy receptacle can be more or less urceolate and closed. In Ficus the syconium is closed at the apex (with a tiny opening protected by phyllaries and called the ostiole) and forms an urn like structure.

c) Complete plate 5 with the missing captions A to K with the words or phrases:

  • Pistillate flower. G
  • Staminate flower perianth. B
  • Style. C
  • Phyllaries. E
  • Staminate flowers. A
  • Pericarp. K
  • Stigmas. F
  • Anther. I
  • Peduncle. D
  • Ovule. J
  • Pistillate flower perianth. H

Relate this Inflorescence to the basic structure found in Plate 4.

The inflorescence is similar but there is only one central pistillate flower. The inflorescence mimics a single flower and is an example of a pseudanth.

Plate 4. Schematic drawing of the basic structure of a Dorstenia inflorescence.

 

Plate 5. Inflorescence, pistillate and staminate flowers in Dorstenia Africana from Berg, Cornelius, The genus Dorstenia (Moraceae) Illicifolia 2).

 

5. Find below plate 6 with line drawings illustrating morphological characters of Geranium subgenus Geranium fruits (Geraniaceae).

a) Complete Plate 6 with the missing captions A to K with the words or phrases:

  • Stylar portion of rostrum. A
  • Rostrum. H
  • Mericarp. D
  • Bristle retention mechanism. G
  • Awn. I
  • Mericarp (empty). J
  • Prong retention mechanism. E
  • Seed. B
  • Stigmas. K
  • Twist retention mechanism. C
  • Central Column. F

b) Describe the Geranium fruit and its dehiscence type.

The fruit is of schizocarpic type. It is derived from 5 fused carpels with one ovule in each locule. This type of capsule has paraplacental explosive dehiscence leaving the placentas and stylar portion of the fruit attached to the receptacle.

c) Describe the seed dispersal and the role of the three seed retention mechanisms.

The three mechanisms Bristle, Prong and Twist allow the seed to be retained in the pre-explosive stage when the mericarps apertures are facing down. Prong type have a terminal awn keeping the seed from dropping,  bristle have terminal hairs and twist place the mericarps perpendicular to the ground.

Plate 6. Fruits of Geranium subgenus Geranium (Yeo, P. 2001 ‘Hardy Geraniums’)

 

 

6.  Find below plate 7 showing photographs of flowers showing the pollination syndrome in the genus Berberis (Berberidaceae).

a) Describe the mechanism of pollination with the help of the photographs. How do Berberis anthers dehisce? 

Berberis anthers dehisce with flaps (valvular). The stamens are located opposite a petal and the filaments are placed in between two nectary glands at the base of the petal. At anthesis the stamens are spreading and the flap are released with the pollen held well above the thecae at the tip of the flaps. After an insect trigger the sensitive stamens move towards the gynoecium.

b) Briefly discuss whether or not such a pollination mechanism could have an adaptative value?

At first we would think this has no adaptive value as the pollinators seem to trigger a self pollination rather than a cross pollination. Though it seems the flaps place the pollen well above the broad stigmas and self pollination may be limited. So this could act as a more targeted place for pollen presentation and fertilization similarly to the mechanism found in secondary pollen pollination or plunger pollination.

c) Which major group of tracheophytes and order does this plant belong to?

Angiosperms; Eudicots; Ranunculales

A

B

C

Plate 7: Flowers of Berberis showing pollination mechanism: A. Mature flower; B. Flower before and after being triggered by a pollinator; C. Flower after being triggered (from Bob Harms, University of Texas, personal communication).

 

7.  Find below plate 8 showing a nomenclature treatment and description for the species Duchesnea indica (Rosaceae).

a) List the name under which this taxon was first described (Basionym). List two other synonyms for Duchesnea indica, one nomenclatural synonym and one taxonomic synonym.

Basionym is Fragaria indica Andrews
Two synonyms; Potentilla indica  (Andrews) T.Wolf. and Fragaria malayana Roxb.

b) What did the author Focke add to the nomenclature of this taxon?

Focke changed the genus of this taxon from Fragaria to Duchesnea.

c) Where was the type specimen of Duchesnea indica published? Explain why a lectotype was chosen.

The type was published in Bot. Reposit. 7: tab.479. 1807.
A lectotype was chosen because no specimen were preserved.

Plate 8: Duchesnea indica in Flora of Pakistan – Rosaceae (I) No. 216 (2009)

 

Home page

Theory

question 1

question 2

question 3

question 4

question 5

question 6

question 7

Practical

Paliurus spina-christi

Nigella damascena

Ornithopus perpusillus

 

 

     

2012 SYSTEMATIC PRACTICAL EXAMINATION

ANSWER ALL QUESTIONS
TIME ALLOWED TWO HOURS

Choose between the two plants provided

1. Using Prenner et al. 2010 'Floral formulae updated for routine inclusion in formal taxonomic description' TAXON 59(1): 241-250, give the floral formula of the flower.          (10 marks)

2. Describe the chosen specimen in terms of both vegetative and reproductive characters.  Make one or more labelled sketches using the glossary (Beentje Henk 'The Kew Plant Glossary' (2010).  (65 marks)

3. Using the key provided, give the species that your specimen belongs to, list the characters that you observed in the plant that lead you to this conclusion.    (25 marks)

Rhamnaceae: Paliurus spina-christi

Common name: Christ’s thorn 

Shrubs deciduous, to 3 m tall. Young branches more or less densely pubescent, mature branches soon glabrescent.

Stipular spines 2 per node; one hook-like, recurved; petiole 3-13 mm, pubescent; leaf blade ovate to elliptic, symmetric to ± asymmetric, 2-4 × 1.5-3.5 cm,  3- to pinnately veined, with 3-6 pairs of secondary veins, base obtuse to cordate, margin inconspicuously serrate, apex obtuse. Abaxial surface with domatia at base of primary veins.

Inflorescence axillary cymes, bracts small.

Flowers 3-6 mm in diameter. Pedicel 4-8 mm, pubescent. Calyx lobes deltoid, green. Petals cucullate, yellow-green and enclosing the stamens at anthesis; stamens distinctly recurved after anthesis. Nectary disk conspicuous intrastaminal. Hypanthium enveloping the ovary but not the styles. Ovary 3- or 4-loculed with axile placentation and one ovule per locule; style 3- or 4-fid.

Fruit drupe like, 1.5-3.5 cm in diam., glabrous, base conical, often with persistent sepals, apex rounded; wing broad and thin, 5-12 mm, papery, margin entire, ± undulate.

Illustration:

1. Flowering branch x1; 2-7. Flowers at anthesis and after anthesis x6; 8-9. Longitudinal section of a flower x6; 10. Gynoecium; 11-12. Cross section of the ovary x10; 13-15. Fruit; 16. Stem, leaf and stipules x1; 17. Erect stipular spine; 18. Abaxial leaf surface and domatia.

Key to Genus and species (Genera A to D; species A to E ) Adapted from Flora of China online www.eFloras.org

Genus Key
1 Stipules spinescent, persistent -2
2 Young twigs puberulous -A

Species Key
1 Stipular spines 2 per node -3
3 Branches with 1 erect and 1 recurved spine per node -C

Floral Formulae: K5-6* C5-6* A5-6* -G(3-4)-*Vx3-4

 

 

 

 

 

 

 

 

 

Ranunculaceae:  Nigella damascena

Common name: love-in-a-mist   

Annual 10-60cm tall.

Leaves 2-3 pinnatisect with linear segments, alternate.

Flowers single and terminal with 5 involucral bracts similar to the cauline leaves. Sepals 5-10, clawed, bluish. Petals 8-10 reduced to honey-leaves. Honey leaves bilabiate with a ciliate mouth and lower lip with two lobes as long as wide. Androecium of many stamens in 5-8 bundles, anthers  mucronate. Gynoecium of 4-5 fused carpels in axile placentation with many ovules in each locule. Styles free recurved.

Fruit and inflated capsule with 10 locules (5 fertile and 5 sterile). Seeds triquetrous, granulate and shortly winged. 

Illustration:

1. Flower x1; 3-4. Capsule x0.5; 5-6. Seed x10; 7-12. Honey-leaf (12 with removed upper lip) x12; 13-16. Androecium x27; 17. Gynoecium x1; 18-19. Cross section of the ovary x7; 20. Cross section of the capsule; 21. Stem; 22. Leaf adaxial surface.

Key to Genus and species (Genera A to AA; species A to N ) Adapted from Flora Europaea Volume  1, 2nd edition

Genus Keys
1 Flowers actinomorphic
4 Leaves alternate or verticillate; perianth-segments imbricate in bud
5 Flowers not spurred
7 Perianth of 2 dissimilar whorls (or apparently so), the inner of which may consist of petaloid honey-leaves
8 Petaloid whorl of the perianth without nectaries
9 Leaves finely divided -H

Species Keys
1 Flowers blue, greenish or reddish; seeds ovoid or triquetrous
3 Anthers not mucronate
4 Flowers with an involucre of leaves
6 Perianth-segments shortly clawed; lobes of lower lip of honey-leaves about as long as wide; fruit 10-celled  -F

 

Floral Formulae: 

B5* K5-10* C8-10honey-leaf ↓ A* G(4-5)* Vx

 

 

 

 

 

 

 

 

 

 

 

 

Fabaceae subfamily Faboideae:  Ornithopus perpusillus

Common name: Bird’s foot 

Procumbent to decumbent annual with stems to 30cm long. Stems pubescent.

Leaves compound, imparipinnate with 5-15 leaflets. Leaflets opposite or pseudo-opposite, with entire margin, ovate. Adaxially and abaxially with sub-appressed long hairs. Base of petiole with small pulvinus and short deciduous stipules. Stipels absent, leaf rachis terete and petiolules to 0.5 mm long.

Inflorescences axillary heads of 3-8 flowers, bracts leaf-like as long as the flowers.

Flowers papilionaceous, white with red-purple lines markings. Flowers 3-5 mm long. Calyx tubular with equal lobes. Banner constricted in the middle and with a basal claw, white with red lines. Wings narrow, horizontal with swollen part in the middle. Keel yellow; keel and wings of similar length but wing slightly exceeding. Androecium of 9 fused stamens in a narrow tube plus one free on the adaxial side. Anthers with a short swollen filament at base. Gynoecium a single carpel, glabrous with an upright style and hidden inside the staminal tube. Stigmas with papillae. Ovary with 4-9 ovules.

Fruits a lomentaceous legume; one seeded segments (lomentum)  falling apart. Seeds not ripe.

Illustration:

1. Flowering branch x2; 2-3. Inflorescence x12; 4-5 Flower x14; 6-7. Banner x12; 8-9. Wing x12; 10-11. Keel x12; 12-13. Gynoecium x15; 14-15. Androecium x15; 16-17. Lomentaceous legume and lomenta x10; 18. Leaf base x9; 19. Leaf rachis; 20. Adaxial leaf surface.

Key to Genus only (Genera A to CCC) Adapted from Stace, C. ‘New Flora of the British Isles’

1 At least some leaves with at least 2 leaflets -2
2 Leaves with 1-many pairs of leaflets, with or without an odd
terminal leaflet, if with then pairs of leaflets > 1, if without then often with tendrils -Key C
Key C 
1 Leaves with odd no. of leaflets, terminated by single leaflet -6
6 Herbaceous, sometimes+ woody at base -10
10 Flowers solitary or in umbels -14
14 Fruit breaking along transverse sutures between seeds -17
17 Fruit-segments and seeds oblong-ellipsoid -18
18 Annuals; flowers <8(12) per inflorescence, 3-9mm -CCC

 

Floral Formulae: B2-3* K(5)* C3+(2)↓ A(9)+1↓ G1↓Vm4-9

 

Practical

Paliurus spina-christi

Nigella damascena

Ornithopus perpusillus