Plant Systematics

Question	Answer
What is a “plant”? In what two conceptual ways can the answer to this question be approached?	a) By the characteristics they possess (cell walls, spores, sedentary, photosynthetic) b) By the evolutionary history of life (systematics)
What are the three major groups of life currently accepted?	Bacteria, Archaea, and Eukarya
Name and define the mechanism for the evolution of chloroplasts.	Endosymbiosis - by the engulfment of an ancestral photosynthetic bacterium (probably a cyanobacterium) by an ancestral eukaryotic cell, such that the photosynthetic bacterium continued to live and ultimately multiply inside the eukaryotic cell.
Name some chlorophyllous organismal groups that have traditionally been called “plants” but that evolved or acquired chloroplasts independently.	euglenoids, dinoflagellates, and brown algae
Draw a simplified cladogram showing the relative relationships among the green plants (Chlorobionta/Viridiplantae), land plants (embryophytes), vascular plants (tracheophytes), seed plants (spermatophytes), gymnosperms, and angiosperms (flowering plants).	Image: tree (image/jpg)
Why are land plants treated as equivalent to “plants” in this book?	Land plants make up a monophyletic group, whereas the photosynthetic eukaryotes as a whole are not monophyletic and, as a group, do not accurately reflect evolutionary history.
List the many ways that plants are important, both in evolution of life on earth and in terms of direct benefits to humans.	Plants were in part responsible for the oxygenation of the earth’s atmosphere, a prerequisite to the evolution of most eukaryotes. Plants are also major primary producers on the land and in some aquatic systems. Thus, most animals are dependent on them.
What is systematics and what is its primary emphasis?	A science that includes and encompasses traditional taxonomy, the description, identification, nomenclature, and classification of organisms, and that has as its primary goal the reconstruction of phylogeny, or evolutionary history, of life.
Define biological evolution, describing what is meant both by descent and by modification.	Descent with modification. Descent is the transfer of genetic material (enclosed within a cell, the unit of life) from parent(s) to offspring over time. Modification is a change in the genetic material that is transferred from parent(s) to offspring, such that the genetic material of the offspring is different from that of the parent(s).
What is a lineage?	A set of organisms interconnected through time and space by the transfer of genetic material from parents to offspring.
Name and define the units that undergo evolutionary change.	Populations and species. A population is a group of individuals of the same species that is usually geographically delimited and that typically have a significant amount of gene exchange. Species are groups of populations that are related to one another by various criteria and that have evolutionarily diverged from other such groups.
What are the two major mechanisms for evolutionary change?	Natural selection and genetic drift.
What is a functional feature that results in increased survival or reproduction called?	An adaptation.
Name and define the four components of taxonomy.	Description is the assignment of features or attributes to a taxon. Identification is the process of associating an unknown taxon with a known one, or recognizing that the unknown is new to science and warrants formal description and naming. Nomenclature is the formal naming of taxa according to some standardized system. Classification is the arrangement of entities (in this case, taxa) into some type of order.
Define character and character state.	Characters are features. Two or more forms of a character are character states
Give one example of a character and character state from morphology or from some type of specialized data.	E.g., “leaf shape,” for which possible character states are “elliptic,” “lanceolate,” and “ovate.”
What is a dichotomous key? A couplet? A lead?	A dichotomous key is an identification device consisting of a series of two contrasting statements. Each statement is a lead; the pair of leads constitutes a couplet
What is a scientific name?	Formal names, which by convention are translated into the Latin language, determined by the International Code of Botanical Nomenclature.
Define binomial and indicate what each part of the binomial is called.	Species names, consisting of two names: a genus name and a specific epithet.
What is the difference between rank and taxon?	Ranks are hierarchical groupings, meaning that each rank is inclusive of all other ranks beneath it. A taxon is a group of organisms typically treated at a given rank.
Name the two main ways to classify organisms and describe how they differ.	Phenetic - based on overall similarity. Phylogenetic - based on evolutionary history.
Define phylogeny and give the name of the branching diagram that represents phylogeny.	Phylogeny, the primary goal of systematics, refers to the evolutionary history of a group of organisms. Cladogram (or phylogenetic tree).
What does a split, from one lineage to two, represent?	Lineage divergence, the diversification of lineages from one common ancestor.
Name the term for both a preexisting feature and a new feature.	Preexisting feature = ancestral character state. New feature = derived character state, also called an apomorphy.
What is phylogenetic systematics (cladistics)?	A methodology for inferring the pattern of evolutionary history of a group of organisms, utilizing apomorphies.
What is a monophyletic group or clade?	A group consisting of a common ancestor plus all (and only all) descendants of that common ancestor.
What is a paraphyletic group?	A group consisting of a common ancestor but not all descendants of that common ancestor.
What is a polyphyletic group?	A group in which there are two or more separate groups, each with a separate common ancestor.
For what can phylogenetic methods be used?	To devise a system of classification, and to address biogeographic or ecological history, processes of speciation, and adaptive character evolution.
How is systematics the foundation of the biological sciences?	Virtually all fields of biology are dependent on the correct taxonomic determination of a given study organism. Systematic research is the basis for acquiring, cataloging, and retrieving information about life’s diversity.
How can systematics be viewed as unifying the biological sciences?	Systematics may utilize data from all fields of biology. The systematist has an opportunity to understand all aspects of his/her group of interest in an overall synthesis of what is known from all biological specialties, with the goal being to understand the evolutionary history and relationships of the group.
How is systematics of value in conservation biology?	In order to determine whether a species or infraspecific taxon of plant is rare or endangered and warrants protection, one must first know the limits of that species or infraspecific taxon. In addition, understanding the history of evolution and geography may aid in conservation and management decisions, where priorities must be set as to which regions to preserve.
Name the major plant organs.	Rhizoids, thallus, shoots, roots, stem, leaf, leaf primordia, veins, costa, buds, sporangium, capsule, cone, strobilus, ovule, seed, flower, fruit.
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.
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.
Name various types of plant habitat.	Plant habitats can include terrestrial, aquatic, epiphytic, submersed, floating, emergent, or saxicolous.
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.
What is the function of roots?	Roots function in absorption of water and minerals and anchorage.
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.
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.
What is a shoot?	A shoot is a stem plus all its associated leaves.
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.
Define node, internode.	A node is the point of attachment of a leaf to a stem, and space between nodes is called the internode.
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.
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.
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.
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.
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.
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.
Draw a typical twig and label terminal bud, axillary bud, leaf scar, vascular bundle scars, lenticels.	Image: twigd (image/jpg)
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.
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.
Name some specialized modifications of leaves associated with flowers or inflorescences.	Bracts, bractlets, bracteoles, chaff or paleae, glumes, lemma, phyllary, spathe.
From what is a phyllode derived?	Phyllodes are derived from ancestrally compound leaves by loss of the rachis and leaflets.
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.
Name three modifications of leaves found in carnivorous plants.	Pitcher leaves, tentacular leaves, and trap leaves.
Name five leaf types.	Simple, pinnately compound, bipinnately compound, palmately compound, trifoliolate, biternate.
What are the basic components of a simple leaf?	Blade, petiole, stipules.
Draw a bipinnately compound leaf and label: leaflet, petiole, petiolule, rachis, rachilla, stipule, stipel.	Image: leaf (image/jpg)
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.
Name four different types of leaf attachment.	Petiolate, sessile, sheathing, decurrent, amplexicaul, perfoliate, and connate-perfoliate.
What is the difference between parallel and penni-parallel? Between pinnate-netted, palmate-netted, and ternate-netted venation?	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.
Name four major types of specialized venation types.	Palinactinodromous, campylodromous, brochidromous, flabellate.
Draw a typical flower and label all the parts, including collective terms.	Image: flower (image/jpg)
Name the two basic types of flower sex.	Perfect (bisexual) and imperfect (unisexual).
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.
Draw a zygomorphic corolla and label anterior lobe(s) and posterior lobe(s).	Image: symmetry1 (image/jpg)
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.
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
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.
What are the two major types of perianth arrangement?	Spiral and whorled.
What is perianth cycly?	Perianth cycly refers to the number of whorls of perianth parts.
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.
Name two types of calyx fusion; of corolla fusion.	Aposepalous and synsepalous; apopetalous and sympetalous.
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.

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