BotanicalBotanical LessonsLessons Plant organisation (1/2)

Leaves of the family Crassulaceae (here the Potatoes are stems that have been modified to 53 example of the houseleek, Sempervivum store nutrient reserves. In common with all stems, montanum) can store water as an adaptation they carry the buds ("eyes") to drought

Flowering plants are composed of three parts: roots, stems and leaves. blade veins Roots. Most often found underground, roots anchor plants to the soil and absorb water and mineral elements required for growth. They can be either taproots (a single vertical root) or fasciculate.

petiole Sometimes roots also store reserves (such as in the carrot). stipules

alternate opposite

The stem. Generally found aboveground, stems carry the buds, which determine the growth, General organisation of a leaf and examples of the arrangements "alternate" and "opposite" ramification and flowering of the plant. Stems maintain the plant upright and are essential for the transport of nutrients (sap). Stems can be herbaceous, or rigid and lignified (wood) in shrubs and trees. Diagram of a plant: roots (in black, here fasciculate, with numerous roots attached to the same point), stem (in brown), leaves (in green) and a flower (in blue). The stolons are Leaves. Leaves are the principal organ of photosynthesis and transpiration. They generally lanceolate ovate obovate orbicular above ground stems which grow horizontally and produce clones of the mother plant. comprise of two parts: the lamina and the petiole. The lamina is a flattened blade containing veins which transport the sap. The shape, margin and pattern of veins differ between species and sagittate pedate pennatilobate cordate constitute criteria for identification. The lamina is divided into leaflets, in the case of leaves called “compound” leaves. The petiole, which is sometimes absent, attaches the leaf to the stem. Phyllotaxy describes the arrangement of leaves on the stem. Leaves can, for example, be grouped palmate paripennate imparipennate An example of a plant with both an A few examples of the diversity of leaf blades. In underground stem, or rhizome (in brown), and in pairs attached face to face along the stem (leaves called "opposite") or be rather isolated and brown, the petiole, in dark green, some an above ground stem; the roots (in black) are examples of "compound" leaves called “adventive” (newly formed on the stem) arranged regularly in a spiral around the stem (leaves called "alternate"). BotanicalBotanical LessonsLessons Plant organisation (2/2)

Two gentians: Gentianella campestris (left, The daffodil (Narcissus poeticus, 53 hemicryptophyte) and Gentiana nivalis (right, a Amaryllidaceae family), an example of a rare alpine therophyte) cryptophyte plant with a bulb

The Danish botanist Christen Raunkiær (1860-1938) developed a classification of plants founded on

A. Phanerophytes (trees, shrubs > 50 cm) their strategies to survive bad winter conditions. This classification is based on the position of plant

Perennial B. Chamephytes subshrubs (a), creeping shrubs (b), plants with woody basee (c) buds during the winter. Phanerophytes are trees and shrubs higher than 50 cm. Their buds are not plants C. Hemicryptophytes rosettes (d), tufts (e) protected from frost by snow cover, which is one of the reasons that trees are absent from the alpine

D. Cryptophytes (ou geophytes) with rhizome (f), or bulb (g) zone. Chamephytes are small shrubs whose buds are sufficiently low to be protected by snow cover. Annual E. Therophytes Numerous cushion plants from dry mountain areas (see the rockery “Spanish mountains”) have plants woody bases and also belong to this category. Hemicryptophytes have their buds located at soil A CD level, and their leaves form either a rosette (such as the Dandelion) or a tussock (such as in numerous e f Poaceae or Cyperaceae). Cryptophytes (also called Geophytes) have their buds buried, and thus

50 cm B E g protected from cold under the ground (geo in Greek). The buds are situated on the rhizomes a cd b (underground stems) or on bulbs which accumulate reserves to fuel the beginning of growth for the next year. Therophytes are annual species. These species pass the winter period as seeds, highly resistant to aridity and frost. Very common in arid areas, annual species are almost non-existent in alpine areas, mostly because of the highly random nature of the possibility for sexual reproduction at high altitudes.

The principal "biological types" based on the position of the buds during winter (in red). In black, the perennial parts of the plant that remain from one year to the next; dotted lines, the plant parts that die during the winter. Etymology of the terms: "phanero", visible; "chamae", dwarf; "hemi", half; "crypto", hidden; "thero", summer. BotanicalBotanical LessonsLessons The concept of the alpine plant (1/2)

The mountain avens (Dryas octopetala, The gentians (here Gentiana acaulis, 53 Rosaceae family), an example of an Gentianaceae family), examples of plants arctic-alpine plant originating from the Himalayan region

Altitudinal vegetation zones. Mountain vegetation is divided into zones, each with a characteristic type of vegetation. The upper limit of the sub alpine zone marks the natural limit (without human

intervention) of trees. This limit is found around 2300 m altitude in the Alps. Higher up is found the alpine South North zone where environmental conditions become more and more extreme with altitude due to decreasing mean temperatures, increasing solar radiation, strong winds, etc. The sub alpine / alpine

NIVAL belt

mosses, lichens boundary varies from 0 m altitude in polar areas, up to above 4000 m in tropical regions. For biologists, ADRET UBAC 2900 m an alpine plant is a species that grows in the alpine zone, in the Alps or another mountain region. Routes of the plant colonisation of the Alps: 1, Mediterranean; 2, Central Asian; 3, Arctic ALPINE belt Determined mostly by temperature, the limit of the alpine zone is rising due to global warming, alpine meadows endangering those plants that grow at high altitudes. The plants growing in the Lautaret alpine garden 3000 m

2400 m come from subalpine and alpine zones. Etage SUBALPIN 2200 m

1700 mconifer forests Multiple origins for the1500 flora m of the Alps. The current alpine flora is the result of a colonisation begun some 1100 m 900 m 10 000 years after the retreat of the glaciers. The major vegetation influences come from the MOUNTAIN belt mixed forests Mediterranean, Central Asian (notably Himalayan) and arctic regions. In the case of the arctic region, the alternation between glaciations and glacial retreat has contributed to numerous exchanges of

COLLINEAN belt flora, resulting in the presence of numerous plant species, called arctic-alpine species, which are found The campanulas (here Campanula alpestris, broadleaved forests Campanulaceae family), a plant with a both in the Alps and in arctic regions. Mediterranean origin BotanicalBotanical LessonsLessons The concept of the alpine plant (2/2)

Swiss androsace (Androsace helvetica, High altitude Dwarf willow (Salix serpyllifolia, 53 Primulaceae family), a cushion plant growing Salicaceae family) an example of a prostrate amongst rocks at the Galibier pass (around 2800 m) plant

25 at the surface of the cushion 20 Morphological adaptations. A small size is very common amongst alpine plants, allowing them to remain within 1 to 2 m of the ground where temperatures are less cold. It also allows plants to benefit 15 from protection by snow cover in winter, and limits the mechanical effects of the wind and snow which 10

at 2 m can break stems and branches. Cushion plants are a well-known example of adaptation to extreme

Temperature(°C) 5 from the cushion conditions: the cushion functions as a heat trap as its geometric form exposes the least surface area to 0 9 12 15 18 external conditions, limiting both losses of heat (and water). Plant hairs are another adaptation: these Hour of the day (summer) The temperature difference between theform a screen that protects the plant from cold, dry and strong solar radiation. Root systems of alpine surface of a cushion plant and at two meters height (using the example of silene acaule) Structure of the Swiss androsace, an example of plants can also exhibit adaptations, such as the presence of a long tap root in cushion plants. a cushion plant with a long tap root

5 alpine plants Physiological adaptations. Alpine plants synthesise molecules (sugars, anti-freeze proteins) which

4 protect their cell membranes from the effects of freezing. They can also maintain their cell contents in 3 a liquid state down to temperatures of -40°C. To counter oxidative stress imposed by excessive solar 2 lowland plants radiation (light and UV), plant can accumulate anti-oxidants, in particular vitamin C. These 1 Vitamin C, micromol/mg chlorophylll micromol/mg C, Vitamin adaptations are the results of long periods of evolution. They are in part fixed in the genetic makeup of 0 132 465 alpine species, and in part dependant on environmental conditions (acclimation). Differences in the concentration of vitamin C in three alpine plants (1, soldanella; 2, alpine coltsfoot; 3, glacier ranunculus) and three The edelweiss (Leontopodium alpinum, lowland plants (1, rye; 2, dandelion; 3,Ces adaptations sont le fruit d'une longue évolution. Elles sont pour partie inscrites dans le patrimoine Asteraceae family), an example of a plant meadow buttercup) covered with protective hairs génétique des espèces et pour partie conditionnées par les conditions environnementales (acclimatation). BotanicalBotanical LessonsLessons Interspecific relationships (1/2)

Mont Cenis restharrow (Ononis cenisia, Lousewort (Pedicularis comosa, Orobanchaceae 53 Fabaceae family), an example of a plant family), an example of a hemiparasitic plant able to fix atmospheric nitrogen

atmospheric nitrogen Plants have multiple types of relationships between each other, and with other organisms (N2) (bacteria, animals). Here are a few examples

organic nitrogen Symbiosis. This is a long term association between two organisms allowing each to obtain (proteins) root reciprocal advantages. Plants such as the sainfoins, trefoils, milk-vetches, restharrows, clovers and roots of the parasite (haustorium) nodules other plants of the family Fabacea, host in their roots (within nodules) bacteria (Rhizobium) which water and (Rhizobium bacteria) mineral nutrients can use atmospheric nitrogen. They transform this into organic nitrogen (amino acids and proteins) Hemiparasitismhost roots Diagram of the symbiosis between the which can then be used by the plant. Similarly, lichens are the result of a symbiosis between a Fabaceae (Leguminaceae) and the bacteria hosted in the nodules of their roots fungus, which provides resistance to drying out, and an algae, which provides the synthesis of sugars by photosynthesis.

CO2 (atmospheric carbon) Parasitism. This is a relationship with negative consequences for one organism. In the case of sugars (organic carbon) hemiparasitism (louseworts, rhinanthus, velvetbells, etc.), one plant accesses water and mineral O2 roots of the fungal unicellular mycelia algae salts in the vessels (roots or stems) of the host plant, but remains green and able to also parasite (haustorium)water and photosynthesise itself. In the case of holoparasitism (such as for the broomrapes and dodder), the mineral nutrients + organic matter Diagram of lichen with the fungal host roots mycelium (in brown) and the unicellular parasite has lost the capacity to photosynthesise itself, and not only uses water and mineral salts algae (in green) Holoparasitism from the host, but also organic matter. BotanicalBotanical LessonsLessons Interspecific relationships (2/2)

Facilitation: lady's mantle (Alchemilla sp) Competition between Festuca paniculata 53 (dissected leaves) benefits from the favou- (large grasses) and other species in grasslands rable microclimate next to a cushion of moss at the Col du Lautaret campion (Silene acaulis)

Carnivory. Carnivorous plants live in wet, poorly oxygenated areas which are low in nitrogen, which is required for the synthesis of amino butterwort leaf acids and proteins. The solution found by these plants consists of trapping insects within their leaves (Butterworts and Droseras have sticky

enzymes leaves) which are then digested by enzymes produced by the leaves. The amino acids that are liberated are then absorbed by the (proteases) insect leaves and are used in the synthesis of proteins by the plant. organic nitrogen (amino acids) Competition and facilitation. these are relationships which are not essential to the survival of one of the partners such as in the case of

An insect digested by the sticky leaves of the butterwort Pinguicula vulgaris parasitism or symbiosis. These types of relationships affect the growth of plants either negatively (competition) or positively (facilitation). (Lentibulariaceae family) In the case of competition, plants compete for light Competition Facilitation No interaction and mineral nutrients, which reduces the growth of less the plant grows less well the plant grows better the plant grows in the same with neighbours with neighbours manner with or without competitive species. In the case of facilitation, one neighbours plant benefits from the environment created by another plant which favourably modifies the microclimate (protection from cold, aridity, excessive solar radiation, etc.).

Plant with neighbouring vegetation Plant without neighbouring vegetation (Neighbour removal)

Diagram showing three types of interactions that can exist between plant species: when plants neighbours are experimentally removed, the plant can either grow better, less well, or in the same manner, which indicates the types of interactions that are occurring between the plant and its neighbours BotanicalBotanical LessonsLessons Plant distributions (1/2)

Saxifraga bryoides (mossy saxifrage), grows only Saxifraga caesia (Mount Cenis saxifrage), grows 53 amongst acid siliceous rocks of the Alps and only amongst alkaline limestone rocks of the some other European mountain areas Alps and some other European mountain areas

Some aspects of the distribution of alpine plants are presented here using the example of the genus Saxifraga (Saxifragaceae family). This genus comprises of more than 400 species, essentially found in the mountains of the temperate and arctic northern hemisphere, with many species found in the Alps.

Some species, called arctic-alpine, such as Saxifraga oppositifolia or S. aizoides, have a broad distribution in the arctic region, in the Alps and other European mountains (1). Initially distributed in 2. The distribution of the two species Saxifraga the arctic, these species migrated towards the south during the period of glaciation. As the glaciers caesia and Saxifraga bryoides, two plants found in the Alps and in other mountain regions 1. Distribution of Saxifraga oppositifolia in Europe, an arctic –alpine species. During the retreated, these species recolonized the arctic as well as the higher areas of the Alps. glacial period, it grew in rocky ice free areas Other species are not present in the arctic region. Saxifraga caesia and S. bryoides (2) are two species with a broad distribution in the Alps and some other mountain massifs. Despite their similar distribution, the two species are not found together as they have different requirements as to the type of areas they grow in, one grows in limestone areas (S. caesia) and the other on silicates (S. bryoides). This is called ecological vicariance. Other species such as Saxifraga biflora only grow in the Alps (endemic species, 3). However, it should be noted that this species also grows on a mountain in Saxifraga oppositifolia, pink flowers) and 3. The distribution of Saxifraga biflora, a species Saxifraga biflora, white flowers) Greece, maybe transported by birds, or maybe as an indicator that previously the species had a which grows only in the Alps (and on Mount Olympus in Greece) much larger distribution (relictual species).temps où l'espèce avait une distribution plus large. BotanicalBotanical LessonsLessons S. hostii S. valdensis

Plant distributions (2/2) S. cochlearis

Saxifraga valdensis, a protected species that Distribution of Saxifraga valdensis (westernAlps), 53 grows in France only in a few locations in the S. hostii (eastern Alps) et S. cochlearis Queyras massif (ssouthern Alps)

The species presented here correspond to three species whose ecological requirements are similar (plants growing in alpine zone rocky areas), but they are found in distinct geographical areas: the eastern Alps in the case of S. hostii; the Maritime Alps for S. cochlearis and the western Alps between France and Italy for S. valdensis. This is a case of geographical vicariance.

In the case of the species shown opposite, scientific research has allowed for an understanding of how these distributions developed. These species (as well as others not shown on the map) are all descended form an ancestral species, Saxifraga cespitosa, which is still found today in arctic regions. During the glacial period, this species migrated towards the south. With the retreat of the glaciers, this species recolonized the arctic areas and also most of the mountains of southern Europe. Within each of these mountain regions, geographical isolation allowed for the divergent evolution of this original species, and for the development of a series of endemic species. A number of these endemic species can be found in this rockery, in the Pyrenees rockery (S. hariotii) or in the "Massif central" rockery (S. cebennensis). BotanicalBotanical LessonsLessons Sexual reproduction

Flowers of the vernalgrass (Anthoxanthum Two insect pollinated plants with very colourful 53 odoratum, Poaceae family), an example of flowers (Peacock-eye pink and the common a plant pollinated by the wind rock-rose)

petal The flower is the central element of sexual reproduction in plants. The flower is the central element of sexual reproduction in plants. It comprises of the fertile parts: stamens (male organs) and carpel (female anther organs), and the sterile parts: petals and sepals. The majority of flowers are hermaphrodites, having both filet stamen

style male and female organs. They can be isolated, or grouped in inflorescences. The stamens are formed of ovary pistil sepal ovule an axis (stalk) supporting at its extremity an anther, often yellow, which contains the pollen grains. The

capitulum carpel consists of an ovary containing the ovules, and one or more styles that end in a stigma, which spike corymb peduncle raceme umbel receives the pollen. Pollen is transported by different vectors. Most often, it is insects that transport pollen, and in this case the evolution of flowers has resulted in the development of attractive features such as The different parts of a flower, shown here for the alpine flax (Linum alpinum, Linaceae family) bright colours, scents, particular forms or sugary nectars. In other cases, it is the wind that transports pollen, and the flowers have no petals and no colour (for example in the Poaceae or the Cyperaceae). Once on the stigma, a pollen grain will fertilise an ovule, which will ultimately become a seed, within a pistil that transforms into a fruit. The fruit aids in the dispersal of the seed by the wind, by animals, by water, composed etc. At high altitude, flowers often have intense colours or flower for longer, to compensate for the rarity umbel panicle thyrse of insect pollinators. Many species also reproduce asexually (clonally) or through apomixis (the

production of seeds and fruits without fertilisation, such as found in the Hawkweeeds. The principal types of inflorescences An example of a compound umbel, typical (location of flowers on a stem). The arrows of the Apiaceae family (Umbelliferae), shown indicate the progression of flowering of the here for the common hogweed (Heracleum flowers shown in red sphondylium) BotanicalBotanical LessonsLessons Clonal reproduction (asexual)

The stolons of the creeping avens (Geum Clonal reproduction allows the violet fescue 53 reptans, Rosaceae) allow the plant to (Festuca violacea, Poaceae) to form mats colonise schist scree slopes which stabilise the slope

Asexual reproduction, which is also called vegetative or clonal reproduction, generates exact copies of the original individual called clones. Asexual reproduction is a more reliable form of reproduction than sexual reproduction as it is independent of the season, of successful pollinisation and of seed dispersal. However, this mode of reproduction does not increase genetic diversity, which limits the evolution of species and their adaptation to changes in their environment. Alpine plants often utilize both types of reproduction, increasing their chances of reproduction in difficult environments. The foxtail grass (Alopecurus gerardi, Numerous shrubs reproduce asexually by layering, in which buds located on branches lying on the Poaceae) has rhizomes which produce clones of the mother plant at their extremities ground begin to develop their own roots (such as in Rhododendrons and the Green Alder). In other

Diagram showing the production, starting with a mother plant (left), of successive clones species, plants can produce spreading aboveground stems called stolons (such as for Geums), or from a horizontal stem (stolon or rhizome) underground stems called rhizomes, which do not have green leaves and whose buds can produce clones (such as in numerous Poaceae, e.g. Alopecurus gerardi) Some plants produce bulbs, which are fleshy buds which detach from the base of leaves and produce clones of the mother plant (such as in the alpine bistort, and the orange lily). It is estimated that for some plants such as Carex curvula, the dwarf willow and the alpenrose, the same clone can be aged numerous hundreds, or even thousands of years old.

Sexual reproduction (flowers) in the alpenrose (Rhododendron ferrugineum, Ericaceae) Flowers (sexual reproduction) and bulbs which also uses clonal reproduction via (clonal reproduction) in the orange lily (Lilium layering bulbiferum var bulbiferum, Liliaceae) BotanicalBotanical LessonsLessons Systematics and classification (1/2)

A drawing of a peony from the book "Éléments Berardia subacaulis Vill., a species described 53 de botanique, ou méthode pour connaître les and named by the botanist from the plantes" published by Tournefort in 1694 Dauphine region, Dominique Villars, in 1789

Systematics is that part of botany that aims to classify plants into group’s best reflecting their similarities Amborellales Nymphaeales Piperales ANCESTRAL GROUPS and differences. The criteria on which this classification is based are morphological characteristics Magnoliales Laurales Commelinales (structure of the flowers and vegetative parts), and more recently cytological characters (cell contents MONOCOTYLEDONS Poales

Asparagales and structure) and genetics (DNA sequences). Liliales Dioscorales Alismatales The Greek philosopher Theophrastus (370-285 BC) developed the first plant classification for 480 plants Ranunculales depending on their size (tree, shrub, or herb) and certain floral characteristics. The French botanist de Buxales

Fagales Rosales Tournefort (1656-1708) established a classification of plants according to the structure of their flowers and Fabales Oxalidales

fruits. It was the Swedish naturalist Carl von Linnaeus who developed a universal nomenclature of living Malvales Brassicales things, called binomial, which is still used today. Each species is identified by two Latin (or Greek) names: Sapindales Geraniales Carl von Linnaeus (1707-1778) the first corresponds to the genus and the second to the species, followed by the name of the author who Saxifragales

Caryophyllales

DICOTYLEDONS first described it. The species are grouped into genera and then into families. For example, the belier peony Ericales Gentianales Lamiales Salanales illustrated opposite is the species arietina, within the genus Paeonia (peony), which belongs to the family Boraginaceae

Asterales Paeoniaceae. Dipsacales Apiales AToday, the comparison of DNA sequences allows the further refinement of classifications based on The phylogeny of flowering plants derived from the comparison of DNA sequences. The centuries of methodical observations, and the adoption of a phylogenetic approach providing links represent evolutionary relationships. The names shown on the right are the "orders" information on the evolutionary history of different species and their evolutionary relationships. which regroup several families. For example Plant labels from the garden using the the "Ranunculales" contain the families nomenclature created by Carl von Linnaeus Ranunculaceae and Papaveraceae BotanicalBotanical LessonsLessons Systematics and classification (2/2)

Alpine Columbine (Aquilegia alpina), a Meadow-rue (Thalictrum aquilegifolium), with 53 nationally rare and protected species. Note its white flowers with numerous stamens. To the hooked nectar spurs the right, the yellow globeflower (Trollius europaeus) Identification key of the principal genera of the Rannunculaceae family present in the Alps For each plant in the rockery, choose between the two alternatives at level 1, and then continue similarly for each choice until arriving at one of the 12 genera (Clematis, Delphinium, Aconitum, etc.). In the case of the genus Aconitum, identify the three alpine species. You can verify your identifications using the plant labels

1. Leaves opposite, climbing plant CLEMATIS 1. Leaves alternate, non-climbing plants 2 2. Flowers irregular, with only one plane of symmetry (zygomorphic) 3 2. Flowers regular, with multiple planes of symmetry (actinomorphic) 4 3. Flowers with a nectar spur DELPHINIUM 3. Flowers without nectar spurs ACONITUM see below 4. Flowers forming a yellow ball (the stamens and pistil are not visible TROLLIUS 4. Flowers open (the stamens and pistil are visible) 5 5. Flowers with 5 hooked nectar spurs AQUILEGIA 5. Flowers without nectar spurs 6 Diagram o f the structure o f a flower: sepals 6. Flowers with small green sepals and small hooked petals HELLEBORUS Diagram of the structure of a flower: sepals 6. Non matching characteristics 7 in green, petals in white, stamens in yellow, 7. Flowers with petals and sepals both present and distinct 8 fruits (achenes) in dark green 7. Flowers with only one type of sterile part (sepals), or completely without petals and sepals 9 Wolfsbane (Aconitum lycoctonum), an 8. Three sepals, flowers purple, blue or white HEPATICA extremely toxic species 8. Five sepals, flowers yellow or white RANUNCULUS 9. Large sepals, resembling petals and very visible and strongly coloured 10 9. Four small sepals that fall very early, coloured stamens, highly dissected compound leaves THALICTRUM 10. Five yellow-orange sepals, kidney shaped leaves CALTHA 10. More than 5 white, purple or pale yellow sepals, very dissected leaves 11 11. Fruits (achenes) with a long feathery style ; Plants often covered with long hairs PULSATILLA 11. Fruits (achenes) with deciduous style. Plants generally with few hairs ANEMONE

A key to some alpine species of the genus Aconitum, all highly toxic species 1. Flowers yellow 2 1. Flowers blue Aconitum napellus 2. Narrow helmet, much taller than wide. Leaves with large lobes Aconitum lycoctonum 2. Helmet only just taller than wide. Leaves with filliform lobes Aconitum anthora Alpine anemone (Pulsatilla alpina): the fruits Kupher’s ranunculus (Ranunculus kupferi), a (achenes) have a long feather-like style species from wet alpine grasslands which grows after fertilisation