CHAPTER 9
PLANT MORPHOLOGY
REVIEW QUESTIONS
PLANT STRUCTURE: GENERAL, ROOTS, AND STEMS/SHOOTS
1. Name the major plant organs.
Rhizoids, thallus, shoots, roots, stem, leaf, leaf primordia, veins, costa, buds, sporangium, capsule, cone, strobilus, ovule, seed, flower, fruit.
2. What are the continuously actively dividing cell regions of a plant called and where are they located?
Apical meristems - occur at the tips of roots and shoots.
3. What is meant by plant habit and what are the types of plant habit?
Plant habit is the general form of the plant in terms of stem duration, branching pattern, development or texture. Types are herb (incl. geophyte), vine (incl. liana), subshrub, shrub, and tree.
4. Name various types of plant habitat.
Plant habitats can include terrestrial, aquatic, epiphytic, submersed, floating, emergent, or saxicolous.
5. Name and define five different types of plant life forms.
therophyte, an annual plant; geophyte, a perennial herb with underground perennating rootstocks such as bulbs, corms, rhizomes; epiphyte, a plant growing on another plant, e.g., Tillandsia (Bromeliaceae); halophyte, a salt-adapted plant; succulent, a plant with fleshy stems (stem succulents, e.g., cacti) or leaves (leaf succulents, e.g., members of Aizoaceae or Crassulaceae); and xerophyte, a plant adapted to live in a dry, generally hot environment.
6. What is the function of roots?
Roots function in absorption of water and minerals and anchorage.
7. What are the root cap, root hair, adventitious root, and lateral root?
Root cap - protects the root apical meristem and provides lubrication as the root grows into the soil.
Root hair - hair-like extensions of epidermal cells that increase surface area for water an mineral absorption.
Adventitious root - root that arises from a non-root organ.
Lateral root - roots that arise from other roots.
8. What is the difference between a taproot and a fibrous root system?
If the primary root is dominant, the plant has a taproot system. If the primary root withers and subsequent roots are adventitious, the plant has fibrous root system.
9. What is a shoot?
A shoot is a stem plus all its associated leaves.
10. What is a bud, where do buds typically develop, and what do they develop into?
A bud is an immature shoot system that develops from a bud primordium in the axil and eventually develop into mature shoot systems of lateral branches, flowers or inflorescences.
11. Define node, internode.
A node is the point of attachment of a leaf to a stem, and space between nodes is called the internode.
12. What is the difference between a bulb, corm, and tuber? Between a rhizome, caudex, and stolon (runner)?
A bulb is a rootstock where the shoot consists of a small amount of vertical stem tissue and many thick, fleshy storage leaves. Corms spherical (globose) stem tissue and have scanty scale-like leaves. Tubers have underground storage stems with outer buds and lacking storage leaves or protective scales.
A rhizome is a rootstock with a horizontal, underground stem with short internodes, while a caudex is an undifferentiated vertical stem, and a stolon is a stem with long internodes that runs on or just below the surface of the ground, generally terminating in a new plantlet.
13. What is the difference between a caudiciform stem and a pachycaul?
A caudiciform stem is a low, swollen, perennial storage stem from which arises annual or nonpersistent photosynthetic shoots. A pachycaul is a woody, trunk-like stem, swollen basally for storage.
14. What is a thorn and how does it differ from a spine or prickle?
A thorn is a sharp modified stem or shoot, while a spine is a sharp modified leaf, and a prickle is a sharp epidermal structure.
15. Define: tiller, burl, pseudobulb, short shoot, tendril.
Tiller - a proliferative grass shoot, typically growing in masses from axillary buds at the base of the stem.
Burl - also called a lignotuber, a largely protective and regenerative stem following fires.
Pseudobulb - a short, erect, aerial storage or propagative stem of some epiphytic orchids.
Short shoot - also called a fascicle, spur shoot, or dwarf shoot. A modified shot with short internodes from which flowers or leaves are born. They enable the production of leaves or reproductive organs relatively quickly, with minimal stem tissue being formed.
Tendril - a long, slender, coiling branch, adapted for climbing.
16. Name the difference between acaulescent and caulescent; between prostrate, repent, and decumbent. What is the corresponding character for all of these?
Acaulescent plants lack above-ground stems other than the inflorescence axis, but caulescent plants have an above-ground stem. Prostrate plants have stems that lie flat on the ground and do not root at the nodes, repent plants have stems that lie on the ground and do root at the nodes, and decumbent plants have stems that are basally prostrate but apically ascending. The character is stem habit.
17. What is the difference between monopodial and sympodial?
Monopodial branching pattern is where the given stem axis is derived from growth of a single apical meristem while sympodial branching pattern is where a given axis is made up of numerous units derived from separate apical meristems.
18. Draw a typical twig and label terminal bud, axillary bud, leaf scar, vascular bundle scars, lenticels.
See Figure 9.6.
19. What is the difference between an axillary, terminal, and pseudoterminal bud? A collateral and superposed bud?
Axillary buds are formed in the axils of leaves, terminal buds are also called apical buds and contain the original apical meristem, and pseudoterminal buds are axillary buds near an aborted terminal apical bud that continue extension growth. Collateral buds are two or more axillary buds that are oriented sideways while superposed buds are two or more axillary buds oriented vertically.
PLANT STRUCTURE: LEAVES
20. What is the difference between a bract and a scale?
A bract is a modified leaf that is smaller and shaped differently from the main photosynthetic leaves, while a scale is a non-green leaf that protects either the apical meristem and leaf primordia, or an underground rootstock as in the internodes of a rhizome.
21. Name some specialized modifications of leaves associated with flowers or inflorescences.
Bracts, bractlets, bracteoles, chaff or paleae, glumes, lemma, phyllary, spathe.
22. From what is a phyllode derived?
Phyllodes are derived from ancestrally compound leaves by loss of the rachis and leaflets.
23. What is a spine and what are the three major types?
A spine is a sharp-pointed leaf, the three major types being leaf spines, petiolar spines, and leaflet spines.
24. Name three modifications of leaves found in carnivorous plants.
Pitcher leaves, tentacular leaves, and trap leaves.
25. Name five leaf types.
Simple, pinnately compound, bipinnately compound, palmately compound, trifoliolate, biternate.
26. What are the basic components of a simple leaf?
Blade, petiole, stipules.
27. Draw a bipinnately compound leaf and label: leaflet, petiole, petiolule, rachis, rachilla, stipule, stipel.
See Fig. 9.9.
28. What is the difference between imparipinnate and paripinnate? Trifoliolate and palmate? Geminate-pinnate and bipinnately compound? Unifoliolate and simple?
A pinnate leaf is imparipinnate if it has a terminal leaflet, but a pinnate leaf is paripinnate if it does not have a terminal leaflet. A compound leaf with only three leaflets is called trifoliolate, but a compound leaf with four or more leaflets arising from a common point is called palmate. A geminate-pinnate leaf is compound with two rachillae, each bearing a pinnate arrangement of leaflets, but a bipinnately compound leaf has two orders of pinnate axes (a compound leaf of compound leaves). A unifoliolate leaf is a single leaflet attached to the apex of a petiole. It is derived from the reduction of an ancestrally compound leaf. A simple leaf bears one continuous blade attached to the stem either by a petiole or other forms.
29. Name four different types of leaf attachment.
Petiolate, sessile, sheathing, decurrent, amplexicaul, perfoliate, and connate-perfoliate.
30. What is the difference between parallel and penni-parallel? Between pinnate-netted, palmate-netted, and Parallel venation is where the primary and secondary veins are parallel to one another, but penni-parallel venation is where secondary veins arise from along the axis of a primary vein and are parallel to one another. Pinnately-netted venation has secondary veins arising along the length of a single primary vein, with veinlets forming an interconnected net-like pattern, while palmate-netted venation is where four or more primary veins arise from a common point at the base of the blade, and ternate-netted venation has three primary veins arising from a common point at the base of the blade.
31. Name four major types of specialized venation types.
Palinactinodromous, campylodromous, brochidromous, flabellate.
PLANT STRUCTURE: FLOWERS AND PERIANTH
32. Draw a typical flower and label all the parts, including collective terms.
See Fig. 9.13.
33. Name the two basic types of flower sex.
Perfect (bisexual) and imperfect (unisexual).
34. Name the three basic types of plant sex. What is the corresponding type of flower sex for each?
Hermaphroditic plants only have bisexual flowers. Monoecious plants only have unisexual flowers, with staminate and pistillate flowers on the same individual. Dioecious plants only have unisexual flowers with staminate and pistillate flowers on different individuals.
35. Draw a zygomorphic corolla and label anterior lobe(s) and posterior lobe(s).
See Fig. 9.14, 9.19 (upper left).
36. What is the difference between radial and biradial symmetry?
Radial symmetry has 3 or more planes of symmetry, while biradial symmetry only has two planes of symmetry.
37. What is the difference between protandrous and protogynous? Between centrifugal and centripetal? Between cleistogamous and chasmogamous? development
Protandrous means stamens developing or pollen release occurring, prior to the maturation of carpels or stigmas being receptive. Protogynous means the reverse.
Centrifugal refers to developing from the center toward the outside while centripetal refers to development from the outside toward the center region
38. What is a claw, corona, hypanthium, limb, lip, lobe, spur, throat, tube?
A claw is an attenuate base of a sepal or petal. A corona is a crown-like outgrowth between stamens and corolla. A hypanthium is a generally tubular or cup-shaped structure a the top rim of which are attached the calyx, corolla and adroecium. A limb is the expanded portion of corolla or calyx above the tube, throat, or claw. A lip is either of two variously shaped parts into which a calyx or corolla is divided. A lobe is a segment of a synsepalous calyx or sympetalous corolla. A spur is a tubular, rounded or pointed projection from the calyx or corolla, functioning to contain nectar. A throat is an open, expanded region of a perianth, usually of a sympetalous corolla. A tube is a cylindrically shaped perianth or region of the perianth, usually of a sympetalous corolla.
39. What are the two major types of perianth arrangement?
Spiral and whorled.
40. What is perianth cycly?
Perianth cycly refers to the number of whorls of perianth parts.
41. What is the difference between dichlamydeous and homochlamydeous?
Dichlamydeous describes a perianth composed of a distinct outer calyx and inner corolla. Homochlamydeous describes a perianth composed of similar parts, each part of a tepal.
42. Name two types of calyx fusion; of corolla fusion.
Aposepalous and synsepalous; apopetalous and sympetalous.
43. Define or draw the following perianth types: bilabiate, campanulate, rotate, salverform, urceolate.
Bilabiate means two-lipped, with two, generally upper and lower segments. Campanulate means bell-shaped, with a basally apopetalous corolla or apotepalous perianth. Rotate means with a short tube and wide limbs oriented at right angles to the tube. Salverform means trumpet-shaped, with a long, slender tube and flaring limbs at right angles to the tube. Urceolate means urn-shaped, expanded at the base and constricted at apex.
44. Draw and label a petal with a claw and limb. What is the name of this perianth type?
See 9.19, lower right. A petal with an attenuate base with an expanded portion above. This is called unguiculate.
45. Define convolute, imbricate, and valvate. What is the corresponding character?
Convolute means imbricate with perianth parts of a single whorl overlapping at one margin, being overlapped at the other. Imbricate means overlapping perianth parts. Valvate means a whorl of perianth parts meeting at the margins, not overlapping. These are perianth aestivation character states.
PLANT STRUCTURE: ANDROECIUM
46. Name the two parts of a stamen; the two parts of an anther.
Anther and filament. Thecae and connective.
47. What is the difference between stamen arrangement and stamen position?
Stamen arrangement is the placement of stamens relative to one another, while stamen postion is position of stamens relative to other, unlike floral parts.
48. What is the difference between didymous, didynamous, and tetradynamous? What is the character?
Didymous means with stamens in two equal pairs, didynamous means with stamens in two unequal pairs, and tetradynamous means with stamens in two groups of four long and two short. The character is stamen arrangement.
49. What is the difference between antipetalous, antisepalous, and diplostemonous?
Antipetalous means stamen postion is in line the petals or corolla lobes, antisepalous means the stamens are positioned between the sepals or calyx lobes, and diplostemonous means the outer whorl of stamens is opposite the sepals and the inner whorl is opposite the petals.
50. Do the above terms refer to stamen arrangement or to stamen position?
Stamen position.
51. What is the difference between exserted and inserted? What is the character?
Exserted means the stamens protrude beyond the perianth, while inserted means the stamens are included with the perianth. The character is stamen insertion.
52. What is the term for fusion of stamens to the corolla?
Epipetalous.
53. What is the term for fusion of all the filaments together?
Monadelphous.
54. What is the term for fusion of the filaments into two groups?
Diadelphous.
55. What is a monothecal anther?
A monothecal anther has one theca with typically two microsporangia.
56. Name three types of anther attachment.
Basifixed, dorsifixed, subbasifixed.
57. Name two types of anther dehiscence with regard to (a) the shape of the opening; (b) the direction of the opening.
a) Poricidal, valular, longitudinal, transverse.
b) extrorse, introrse, latrorse.
58. What is a nectary and what are some types of nectaries?
Nectaries are specialized nectar-producing structures of the flowers. Perigonal nectaries and septal nectaries are two types.
PLANT STRUCTURE: GYNOECIUM
59. What is the difference between a gynoecium, carpel, and pistil?
A gynoecium is all female organs of a flower. A carpel is a unit of the gynoecium that collectively makes a pistil. A pistil is composed of an ovary, one or more styles, and or one or more stigmas.
60. What are the three parts of a pistil? What is a locule?
Pistils are made of ovaries, styles, and stigmas. A locule is an ovary cavity, enclosed by the ovary walls and septa.
61. Name the two types of gynoecial fusion.
Apocarpous and syncarpous (also unicarpellous, but not really a fusion, as there is only 1 carpel).
62. How is carpel number determined?
If the gynoecium is apocarpous (carpels distinct), then the number of carpels is equal to the number of pistils. If there is only one pistil, the carpel number can be one or more fused carpels. If there is one pistil, the carpel number is equal to the number of stigmas or styles, if greater than one. If a single pistil has only one stigma or style, the ovary must be dissected to reveal the carpel number. If a single pistil has one stigma or style and is unilocular, the number of carpel is equal to the number of placentae.
63. Name and draw the two basic types of ovary attachment and ovary position.
Sessile and stipitate. See Fig. 9.30.
Superior and inferior. See Fig. 9.32.
64. What does perianth/androecial position mean? Name and distinguish between four of these.
This term describes the placement of the perianth and androecium relative to both the ovary and to a hypanthium, if present.
Hypogynous means the sepals, petals, and stamens are attached the base of a superior ovary. Epigynous means the sepals, petals and stamens are attached at the apex of an inferior ovary. Epihypogynous means the sepals, petals and stamens are attached at the middle of the ovary. Perigynous means the hypanthium is attached at the base of the ovary.
65. What is the difference between axile and parietal placentation? Between basal and apical?
Axile means the placentae are arising from a column in a compound ovary with septa. Parietal means placentae are on the ovary walls or upon protruding partitions of a unilocular, compound ovary. Basal means a placenta occurs at the base of an ovary, while apical means a placenta occurs at the top of a septate ovary.