How to Use This Section
Plant Kingdom rewards two things: precise recall of named genera and a firm grip on ploidy. Almost nothing else is asked. So the 37 items here are weighted towards exactly those two, with a third group on comparisons.
They are organised in three tiers:
- Concept Checks - definitions, characters and named examples.
- Application and Scenarios - an unnamed organism to place, a ploidy to determine, a comparison to draw.
- Analytical and Multi-Concept - reasoning that runs across two or more groups.
Every item is set as a Question with a worked Answer, written the way you would write it in the exam.
Coverage of the chapter-end exercises
| Exercise | Where it is answered |
|---|---|
| 1 - The basis of classification of algae | Question 1 |
| 2 - When and where reduction division takes place in a liverwort, a moss, a fern, a gymnosperm and an angiosperm | Question 15 |
| 3 - Three groups of plants that bear archegonia, and the life cycle of one of them | Questions 22 and 27 |
| 4 - The ploidy of the eight named cells | Question 14 |
| 5 - A note on the economic importance of algae and gymnosperms | Question 23 |
| 6 - Why gymnosperms and angiosperms are classified separately although both bear seeds | Question 26 |
| 7 - What heterospory is, its significance, and two examples | Question 25 |
| 8 - Protonema, antheridium, archegonium, diplontic, sporophyll and isogamy, each with an example | Questions 7, 5, 6, 8, 4 and 3 |
| 9 - Red algae against brown algae, liverworts against mosses, homosporous against heterosporous pteridophytes | Questions 18, 19 and 20 |
| 10 - Matching Chlamydomonas, Cycas, Selaginella and Sphagnum with their groups | Question 13 |
| 11 - The important characteristics of gymnosperms | Question 37 |
Every chapter-end exercise is worked here, so this section is the one place to check that you have covered the textbook in full.
The Facts These Items Draw On
Classification systems. Artificial - gross superficial characters, Linnaeus's androecium system, separated close relatives. Natural - natural affinities plus ultrastructure, anatomy, embryology, phytochemistry; Bentham and Hooker. Phylogenetic - evolutionary relationships, common ancestry. Aids - numerical, cyto- and chemotaxonomy.
Algae. Chlorophyll-bearing, simple, thalloid, autotrophic, largely aquatic. Isogamy (Ulothrix, Spirogyra), anisogamy (Eudorina), oogamy (Volvox, Fucus). Green - chl a, b; starch; cellulose; 2-8 equal apical. Brown - chl a, c, fucoxanthin; mannitol, laminarin; cellulose + algin; 2 unequal lateral; holdfast, stipe, frond. Red - chl a, d, phycoerythrin; floridean starch; cellulose, pectin, poly sulphate esters; no flagella.
Bryophytes. Amphibians; gametophyte dominant and haploid; antheridium - biflagellate antherozoids; flask-shaped archegonium - one egg; dependent sporophyte of foot, seta, capsule. Liverworts - thalloid, dorsiventral, gemmae in gemma cups, Marchantia. Mosses - protonema then leafy stage, Funaria, Polytrichum, Sphagnum; peat.
Pteridophytes. First vascular land plants; sporophyte dominant, true root, stem, leaves; microphylls / macrophylls; sporophylls, strobili; prothallus free-living; homosporous majority, heterosporous Selaginella and Salvinia; precursor to seed habit. Classes - Psilopsida, Lycopsida, Sphenopsida, Pteropsida.
Gymnosperms. Naked ovules and seeds; Sequoia; mycorrhiza in Pinus, coralloid roots in Cycas; male and female strobili; pollen grain = reduced male gametophyte; four megaspores, one develops; two or more archegonia; gametophytes not free-living; air currents and pollen tube.
Angiosperms. Flowers, seeds in fruits, Wolffia to Eucalyptus, dicots and monocots.
Tier 1 - Concept Checks
Question 1
Q. What is the basis of classification of algae?
Answer. Major pigments, stored food, cell wall composition, and the number and position of insertion of flagella.
Takeaway: This is one of the chapter-end exercises.
Question 2
Q. Define algae.
Answer. Chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic organisms, of both fresh water and marine habitats.
Question 3
Q. Explain the term isogamy with an example.
Answer. Isogamy is the fusion of two gametes similar in size. The gametes may be flagellated, as in Ulothrix, or non-flagellated and non-motile, as in Spirogyra.
Takeaway: This is one of the chapter-end exercises.
Question 4
Q. Explain the term sporophyll with an example.
Answer. A sporophyll is a leaf-like appendage that subtends a sporangium. In some pteridophytes sporophylls form compact structures called strobili or cones, as in Selaginella and Equisetum. In gymnosperms, microsporophylls and megasporophylls are arranged spirally to form male and female cones.
Takeaway: This is one of the chapter-end exercises.
Question 5
Q. Explain the term antheridium with an example.
Answer. The antheridium is the male sex organ of bryophytes and pteridophytes. It is multicellular, and it produces biflagellate antherozoids, as in Funaria.
Takeaway: This is one of the chapter-end exercises.
Question 6
Q. Explain the term archegonium with an example.
Answer. The archegonium is the female sex organ of bryophytes, pteridophytes and gymnosperms. It is multicellular and flask-shaped, and it produces a single egg, as in Marchantia.
Takeaway: This is one of the chapter-end exercises.
Question 7
Q. Explain the term protonema with an example.
Answer. The protonema is the first stage of the moss gametophyte. It develops directly from a spore and is creeping, green, branched and frequently filamentous, as in Funaria. The leafy stage then arises from the secondary protonema as a lateral bud.
Takeaway: This is one of the chapter-end exercises.
Question 8
Q. Explain the term diplontic with an example.
Answer. In a diplontic life cycle the diploid sporophyte is the dominant, photosynthetic, independent phase, and the gametophyte is reduced to a few cells or to the gametes themselves. Examples: all seed plants - gymnosperms and angiosperms - and, among algae, Fucus. Meiosis occurs in the sporophyte: at spore formation in the seed plants, and at gamete formation in Fucus.
Takeaway: This is one of the chapter-end exercises.
Question 9
Q. Which pigment gives red algae their colour, and what do they store?
Answer. r-phycoerythrin; they store floridean starch.
Question 10
Q. Why are bryophytes called amphibians of the plant kingdom?
Answer. Because they can live in soil but are dependent on water for sexual reproduction.
Question 11
Q. Name the two heterosporous pteridophyte genera.
Answer. Selaginella and Salvinia.
Question 12
Q. Name the four classes of pteridophytes.
Answer. Psilopsida, Lycopsida, Sphenopsida and Pteropsida.
Tier 2 - Application and Scenarios
Question 13
Q. Match the following. Column I: (a) Chlamydomonas (b) Cycas (c) Selaginella (d) Sphagnum Column II: (i) Moss (ii) Pteridophyte (iii) Algae (iv) Gymnosperm
Answer.
| Column I | Column II |
|---|---|
| (a) Chlamydomonas | (iii) Algae - a green alga of Chlorophyceae |
| (b) Cycas | (iv) Gymnosperm - unbranched stem, coralloid roots |
| (c) Selaginella | (ii) Pteridophyte - Lycopsida, microphyllous, heterosporous |
| (d) Sphagnum | (i) Moss - the peat moss |
Takeaway: This is one of the chapter-end exercises.
Question 14
Q. Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in a dicot; leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of a monocot; ovum of a liverwort; zygote of a fern.
Answer.
| Cell | Ploidy |
|---|---|
| Protonemal cell of a moss | n |
| Primary endosperm nucleus in a dicot | 3n |
| Leaf cell of a moss | n |
| Prothallus cell of a fern | n |
| Gemma cell in Marchantia | n |
| Meristem cell of a monocot | 2n |
| Ovum of a liverwort | n |
| Zygote of a fern | 2n |
Working rule: anything that is part of, or produced by, the gametophyte is n; anything belonging to the sporophyte is 2n; the primary endosperm nucleus is 3n because a male gamete fuses with two polar nuclei.
Takeaway: This is one of the chapter-end exercises.
Question 15
Q. When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Answer.
| Plant | When | Where |
|---|---|---|
| Liverwort | At spore formation | Capsule of the sporophyte |
| Moss | At spore formation | Capsule of the sporophyte |
| Fern | At spore formation | Spore mother cells in the sporangium |
| Gymnosperm | At microspore and megaspore formation | Microsporangium and megasporangium |
| Angiosperm | At microspore and megaspore formation | Anther and ovule |
In all five, meiosis happens in the sporophyte, at spore formation - never in the gametophyte.
Takeaway: This is one of the chapter-end exercises.
Question 16
Q. An alga has chlorophyll a and d, stores floridean starch, and has no flagella at any stage. Name its class and two genera.
Answer. Rhodophyceae, the red algae. Chlorophyll a and d with phycoerythrin, floridean starch and the complete absence of flagella are all diagnostic. Genera: any two of Polysiphonia, Porphyra, Gracilaria, Gelidium.
Question 17
Q. A plant body has a holdfast, a stipe and a frond. Name the class, the stored food and the pigment responsible for its colour.
Answer. Phaeophyceae, the brown algae. Stored food: mannitol or laminarin. Colour pigment: the xanthophyll fucoxanthin.
Question 18
Q. Differentiate between red algae and brown algae.
Answer.
| Red algae | Brown algae | |
|---|---|---|
| Pigments | Chlorophyll a, d; r-phycoerythrin | Chlorophyll a, c; fucoxanthin, carotenoids, xanthophylls |
| Stored food | Floridean starch | Mannitol, laminarin |
| Cell wall | Cellulose, pectin, poly sulphate esters | Cellulose and algin |
| Flagella | Absent | Two, unequal, lateral |
| Body | Multicellular thalli, some complex | Holdfast, stipe, frond; up to 100 m in kelps |
| Sexual reproduction | Oogamous with complex post-fertilisation development | Isogamous, anisogamous or oogamous |
| Examples | Polysiphonia, Porphyra, Gracilaria, Gelidium | Ectocarpus, Dictyota, Laminaria, Sargassum, Fucus |
Takeaway: This is one of the chapter-end exercises.
Question 19
Q. Differentiate between liverworts and mosses.
Answer.
| Liverworts | Mosses | |
|---|---|---|
| Gametophyte | Thalloid, dorsiventral, appressed to substrate | Two stages - protonema, then leafy stage with spirally arranged leaves |
| Asexual reproduction | Fragmentation and gemmae in gemma cups | Fragmentation and budding in the secondary protonema |
| Sporophyte | Foot, seta, capsule | Foot, seta, capsule - more elaborate |
| Spore dispersal | Simple | Elaborate mechanism |
| Example | Marchantia | Funaria, Polytrichum, Sphagnum |
Takeaway: This is one of the chapter-end exercises.
Question 20
Q. Differentiate homosporous and heterosporous pteridophytes.
Answer.
| Homosporous | Heterosporous | |
|---|---|---|
| Spores | All of similar kinds | Macro (large) and micro (small) spores |
| Gametophytes | One kind | Megaspore to female, microspore to male gametophyte |
| Female gametophyte | Free-living, shed from the parent | Retained on the parent sporophyte for variable periods |
| Embryo development | In an independent prothallus | Within the female gametophyte, on the parent |
| Occurrence | The majority | Selaginella, Salvinia |
| Significance | - | Precursor to the seed habit |
Takeaway: This is one of the chapter-end exercises.
Question 21
Q. A gymnosperm has an unbranched stem, pinnate leaves that persist for a few years, and specialised roots hosting nitrogen-fixing cyanobacteria. Name it, and name the roots.
Answer. The plant is Cycas. The roots are coralloid roots, and they are associated with nitrogen-fixing cyanobacteria. (For contrast, Pinus has branched stems and mycorrhizal roots.)
Question 22
Q. Name three groups of plants that bear archegonia.
Answer. Bryophytes, pteridophytes and gymnosperms. Angiosperms do not - their female gametophyte is the embryo sac and no archegonium is formed.
Takeaway: This is one of the chapter-end exercises.
Question 23
Q. Write a note on the economic importance of algae and gymnosperms.
Answer.
Algae
- Algae do at least half of the total carbon dioxide fixation on earth through photosynthesis, and they also raise dissolved oxygen in their surroundings.
- They are primary producers of energy-rich compounds forming the basis of the food cycles of all aquatic animals.
- About 70 species of marine algae are used as food, including many species of Porphyra, Laminaria and Sargassum; Chlorella, rich in proteins, is a food supplement used even by space travellers.
- Hydrocolloids - water-holding substances - come from them commercially: algin from brown algae and carrageen from red algae. Agar, from Gelidium and Gracilaria, is used to grow microbes and in ice-creams and jellies.
Gymnosperms
- They include medium-sized to tall trees and shrubs, so they are important sources of timber and wood; the giant redwood Sequoia is one of the tallest tree species.
- Conifers provide softwood, resins and paper pulp.
- Cycas and Pinus are widely grown as ornamentals.
- Cycas carries coralloid roots with nitrogen-fixing cyanobacteria, which enrich the soil.
Takeaway: For algae the marks are in the named products and their sources; for gymnosperms, in the habit and the wood. This is one of the chapter-end exercises.
Question 24
Q. Arrange these in the order in which they first appear in the plant kingdom: enclosed seed, vascular tissue, naked seed, heterospory.
Answer. Vascular tissue to heterospory to naked seed to enclosed seed.
- Vascular tissue - pteridophytes, the first terrestrial plants to possess xylem and phloem.
- Heterospory - within pteridophytes, in Selaginella and Salvinia, and it is the precursor to the seed habit.
- Naked seed - gymnosperms, whose ovules are not enclosed by any ovary wall.
- Enclosed seed - angiosperms, whose seeds are enclosed in fruits.
Tier 3 - Analytical and Multi-Concept
Question 25
Q. What is heterospory? Briefly comment on its significance. Give two examples.
Answer. Heterospory means making two kinds of spores by the same plant - macro (large) megaspores and micro (small) microspores. Homosporous plants, by contrast, make spores that are all of similar kinds.
Significance. The megaspores and microspores germinate to give female and male gametophytes respectively, so sexes separate at the spore stage. The female gametophytes are retained on the parent sporophytes for variable periods, and the development of the zygotes into young embryos takes place within the female gametophytes. An embryo, fed and protected on the parent plant, is basically what a seed is - so this event is a precursor to the seed habit, an important step in evolution.
Examples. Selaginella and Salvinia.
Takeaway: This is one of the chapter-end exercises.
Question 26
Q. Both gymnosperms and angiosperms bear seeds. Why are they classified separately?
Answer. Because a whole structure is present in one and absent in the other.
- In gymnosperms the ovules are not enclosed by any ovary wall and remain exposed both before and after fertilisation, so the seeds are naked. The reproductive structures are strobili or cones bearing microsporophylls and megasporophylls.
- In angiosperms the pollen grains and ovules develop in specialised structures called flowers, and because there is a closed ovary whose wall matures into a fruit, the seeds are enclosed in fruits.
So having seeds makes both of them seed plants, and the flower and the closed ovary make them two separate groups.
Takeaway: This is one of the chapter-end exercises.
Question 27
Q. Briefly describe the life cycle of a moss.
Answer.
- A haploid spore germinates into the protonema - creeping, green, branched and frequently filamentous.
- The secondary protonema produces a lateral bud that grows into the leafy stage - upright slender axes with spirally arranged leaves, anchored by multicellular branched rhizoids. This is the gametophyte, and it is haploid.
- Antheridia and archegonia form at the apex of the leafy shoots. The antheridium releases biflagellate antherozoids; the flask-shaped archegonium holds a single egg.
- Antherozoids are released into water, reach the archegonium and one fuses with the egg to give the diploid zygote.
- The zygote does not divide meiotically at once; it builds the sporophyte - foot, seta and capsule - which is attached to the gametophyte and derives nourishment from it.
- Meiosis occurs in the capsule, producing haploid spores, released by an elaborate dispersal mechanism to begin the cycle again.
Takeaway: This is one of the chapter-end exercises.
Question 28
Q. Compare the degree of independence of the gametophyte across bryophytes, pteridophytes and gymnosperms, and state what drives the trend.
Answer.
- Bryophytes: the gametophyte is the main plant body - fully independent - while the sporophyte is not free-living and depends on it.
- Pteridophytes: the gametophyte is a small but free-living, mostly photosynthetic prothallus; the sporophyte is now dominant and also independent.
- Gymnosperms: neither gametophyte has an independent free-living existence; both remain within the sporangia retained on the sporophytes.
The driver is water. A free-living gametophyte must sit in cool, damp, shady places and needs water to move antherozoids to the archegonium, which is exactly why pteridophyte distribution is restricted to narrow geographical regions. Enclosing the gametophytes inside the sporophyte removes both constraints, and pollen carried in air currents with a pollen tube replaces swimming gametes.
Question 29
Q. A single sporophyte plant produces spores of two distinct sizes. Predict everything you can about its reproduction.
Answer. The plant is heterosporous.
- The large megaspores will germinate into female gametophytes; the small microspores into male gametophytes.
- The female gametophyte will be retained on the parent sporophyte for a variable period rather than being shed.
- The zygote will develop into a young embryo within the female gametophyte, on the parent plant.
- This makes the plant a candidate for the precursor to the seed habit.
- If it is a pteridophyte, it is most likely Selaginella or Salvinia. If it is a seed plant, heterospory is universal - gymnosperms are heterosporous, producing haploid microspores and megaspores - and the male gametophyte will be a pollen grain.
Question 30
Q. Why can a bryophyte never grow tall, and what change removed that limit?
Answer. Because the bryophyte body lacks true roots, stem or leaves and has no vascular tissue. Without xylem there is no way to lift water against gravity, and without phloem no way to export food from the photosynthetic surface, so the body must stay thallus-like, prostrate or erect but small and close to moisture, absorbing over its surface and anchored only by rhizoids.
The change came with pteridophytes, the first terrestrial plants to possess vascular tissues - xylem and phloem. Their main body is a sporophyte differentiated into true root, stem and leaves, and these organs possess well-differentiated vascular tissues. Height, and everything that follows from it, becomes possible from that point on.
Question 31
Q. Two algae are both isogamous, yet one has swimming gametes and the other does not. What does this tell you about how isogamy is defined, and name both.
Answer. It tells you that isogamy is defined by the size of the fusing gametes, not by their motility. Ulothrix has flagellated isogametes and Spirogyra non-flagellated, non-motile ones; in each species the two fusing gametes match each other in size, so both are isogamous.
Motility enters the definitions only at oogamy, where a large, non-motile female gamete fuses with a smaller, motile male gamete, as in Volvox and Fucus. Anisogamy sits between the two, defined purely on dissimilar size, as in Eudorina.
Question 32
Q. Explain why the pollen grain, not the microspore, is called the male gametophyte.
Answer. Because of what each one is in the alternation of generations. The microspore is a spore - the immediate haploid product of meiosis in the microsporangium, and the last structure belonging to the spore-producing generation.
When the microspore divides, it produces a male gametophytic generation which is highly reduced and confined to only a limited number of cells, and this reduced gametophyte is called a pollen grain. A gametophyte is by definition the phase that produces gametes, and it is the pollen grain, through its pollen tube carrying the male gametes, that does so.
So: microspore = spore; pollen grain = gametophyte; the contents the pollen tube discharges = gametes. Three different things, and questions routinely offer all three as options.
Question 33
Q. Trace the fate of a single megaspore mother cell in a gymnosperm, naming ploidy at each step.
Answer.
- The megaspore mother cell differentiates from one of the cells of the nucellus. The nucellus is part of the sporophyte, so this cell is 2n.
- The nucellus protected by envelopes is the ovule - also 2n tissue, borne on megasporophylls that may cluster into female cones.
- The mother cell divides meiotically to form four megaspores, each n.
- One of the four, enclosed within the megasporangium, develops into a multicellular female gametophyte bearing two or more archegonia - all n. The other three abort.
- The female gametophyte is retained within the megasporangium and never lives independently.
- After the pollen tube discharges the male gametes near the mouth of the archegonia, fertilisation gives a 2n zygote, which develops into an embryo, and the ovule becomes a naked seed.
Question 34
Q. Discuss how the systems of classifying flowering plants changed, and what each change fixed.
Answer.
- Artificial systems went on gross superficial morphological characters - habit, colour, number and shape of leaves - mostly vegetative characters or the androecium structure, as in the system given by Linnaeus. With so few characters to go on, they separated closely related species. And by giving vegetative and sexual characters equal weightage they let environmental variation drown out real affinity, because vegetative characters are more easily affected by environment.
- Natural systems fixed both defects by resting on natural affinities and adding internal features - ultrastructure, anatomy, embryology and phytochemistry. The classification of flowering plants by George Bentham and Joseph Dalton Hooker is of this kind.
- Phylogenetic systems, now accepted, go further and classify on evolutionary relationships, assuming that organisms of the same taxa have a common ancestor.
- Because fossil evidence is often absent, three aids support this: numerical taxonomy - all observable characters coded and computer-processed, each character given equal importance with hundreds considered at once; cytotaxonomy - chromosome number, structure and behaviour; and chemotaxonomy - chemical constituents of the plant.
Question 35
Q. A student claims that because both bryophytes and pteridophytes need water for fertilisation, they must have the same life-cycle pattern and the same dominant phase. Assess this.
Answer. Half right, and the half that is wrong matters.
Right: both are haplo-diplontic, with two multicellular phases alternating. And both do need water for the antherozoids to reach the archegonium.
Wrong: the dominant phase differs. In bryophytes the gametophyte is the main plant body and the sporophyte is not free-living, being attached to the gametophyte and deriving nourishment from it. In pteridophytes the sporophyte is the main plant body, with true root, stem and leaves and vascular tissue, while the gametophyte is the small but free-living prothallus.
The lesson: needing water is about fertilisation; the dominant phase is about which generation the plant body belongs to. Two independent facts, and a question can test either.
Question 36
Q. Take one character from each group - thalloid body, dependent sporophyte, free-living prothallus, naked seed, enclosed seed - and arrange the five groups in order, explaining what each character marks.
Answer.
| Character | Group | What it marks |
|---|---|---|
| Thalloid body | Algae | No differentiation into root, stem or leaf; no vascular tissue |
| Dependent sporophyte | Bryophytes | A multicellular diploid phase appears, but cannot support itself; the gametophyte still dominates |
| Free-living prothallus | Pteridophytes | Both phases now independent, and the sporophyte takes over as the dominant one, with vascular tissue and true organs |
| Naked seed | Gymnosperms | The gametophytes lose independence and stay on the sporophyte; fertilisation no longer needs water; the ovule becomes a seed, but is not enclosed by any ovary wall |
| Enclosed seed | Angiosperms | Flowers appear and the seed is enclosed in a fruit |
Takeaway: Read the middle column downwards and you have the order of the chapter; read the right column downwards and you have the reason the order is what it is.
Question 37
Q. Describe the important characteristics of gymnosperms.
Answer.
- Naked seeds. The ovules are not enclosed by any ovary wall and remain exposed both before and after fertilisation, so the seeds that develop after fertilisation are not covered. The name says it - gymnos means naked, sperma means seeds.
- Habit. They are medium-sized to tall trees and shrubs, and the giant redwood Sequoia is one of the tallest tree species.
- Roots. Generally tap roots. Some genera carry a fungal association, mycorrhiza in Pinus; others carry small specialised coralloid roots associated with nitrogen-fixing cyanobacteria, as in Cycas.
- Stems and leaves. Stems are **unbranched in *Cycas, **branched in *Pinus* and *Cedrus. Leaves may be simple or compound, and the pinnate leaves of *Cycas* persist for a few years. The leaves are well-adapted to withstand extremes of temperature, humidity and wind; in conifers the needle-like leaves reduce the surface area, and a thick cuticle with sunken stomata cuts water loss further.
- Heterospory and cones. Gymnosperms are heterosporous - they produce haploid microspores and megaspores in sporangia borne on sporophylls, which are arranged spirally along an axis to form lax or compact strobili or cones. Strobili bearing microsporophylls and microsporangia are male strobili; those bearing megasporophylls with ovules are female strobili. Both may be borne on the same tree in Pinus, but in Cycas the male cones and megasporophylls are borne on different trees.
- Gametophytes. The microspore develops into a male gametophytic generation that is highly reduced and confined to a limited number of cells - the pollen grain. The megaspore mother cell divides meiotically to form four megaspores, and one of them develops into a multicellular female gametophyte bearing two or more archegonia. Neither gametophyte has an independent free-living existence; both remain within the sporangia retained on the sporophyte.
- Fertilisation and the seed. Pollen grains are carried in air currents to the opening of the ovules. The pollen tube carrying the male gametes grows towards the archegonia and discharges its contents near their mouth. The zygote then develops into an embryo and the ovule into a seed, and that seed is not covered.
Takeaway: Answer this under seven heads in this order - naked seed, habit, roots, stem and leaves, cones, gametophytes, fertilisation and seed. This is one of the chapter-end exercises.