lab manual

 

<< Lab 9 Gymnosperms: Gnetales (Ephedraceae); Pinales (Pinaceae, Cupressaceae, Taxaceae); Lycophytes: Lycopodiales (Lycopodiaceae, Selaginellaceae, Isoetaceae); Monilophytes: Equisetales (Equisetaceae); Polypodiales (Blechnaceae, Dennstaedtiaceae, Dryopteridaceae, Woodsiaceae, Polypodiaceae, Pteridaceae); Salviniales (Azollaceae); Ophioglossales (Ophioglossaceae)  

 

As explained in lecture, gymnosperms are vascular plants that bear ovules and seeds but not flowers - they lack carpels and so their seeds are uncovered. The gymnosperms of California are woody trees and shrubs that usually bear their ovules and seeds in cones on cone scales. Usually, there are two types of cones which may be on the same plant or different plants: a) pollen cones and b) seed (or ovulate) cones. Gymnosperms are often wind-pollinated, and since they lack carpels, the pollen from the pollen cones lands directly on the ovules in the ovulate cones; once pollinated, the ovules mature into seeds.

Their leaves often have "decurrent" leaf bases, meaning that the leaf base is adherent to the stem for some distance. The stems often look green, because they are actually covered with leaf bases. The leaf blades are often flattened or linear needles; sometimes they are awl-shaped. All of our gymnosperm species are evergreen.

Pinales

Pinaceae - A family of 10 genera, of which we have 5 in California. These are monoecious trees and shrubs of many different plant communities. The leaves are flattened or linear needles, arranged alternately or grouped into bundles. The cone scales are in an alternate spiral. The pollen cones have papery scales that fall off easily. The seed cones have thicker, often woody, scales; characteristics of the seed cones are often important in recognizing the genera and species.

  • Pinus "pine"
    This is our most common genus of gymnosperm in California, dominating many of our mountain plant communities. There are three types of leaves in pines: there are scale-like leaves that cover the branches with their leaf bases; there are obvious needles that are grouped into bundles; and there are the sheath leaves that surround the needles at their base and group the needles into bundles (there are cases where there is only one needle per bundle, but sheath leaves will still be present). Make sure that you can see all three types of leaves.
    The seed cones have woody tongue-shaped scales which may be prickly at the tip. The seed cones can last for years on the tree or on the ground. The pollen cones are much more fragile and short-lived. In some species of pine, the seed cone scales do not open when the seeds are mature; rather, the cones scales stay closed for years, either until the heat of a fire opens them or they open gradually after a long time. Such pines are called "closed-cone pines", and their seeds often require a fire for successful germination.

The following species of pine may be available in lab:

  • P. ponderosa "ponderosa or yellow pine"
    A three-needle pine with relatively long, yellow-green needles and prickly seed cones. The bark has large plates and is not supposed to smell vanilla- or pineapple-like (but sometimes it does). This species dominates large areas of the lower elevations of the Sierra Nevada (the ponderosa pine belt).

  • P. jeffreyi "Jeffrey pine"
    This species resembles ponderosa pine, but it is less common, being found at higher elevations and on serpentine. The bark is darker than in ponderosa pine and is supposed to smell vanilla- or pineapple-like. The needles are supposed to be blue-green. The seed cones have prickles at the tips of the scales, but the prickles are longer than in ponderosa pine and are bent under, so that when you pick a cone up, it doesn't actually prick you.

  • P. sabiniana "foothill or gray pine"
    This is a very common, droopy-looking pine found in the foothills circling the valley. The groups of 3 grey-green needles droop down, the leaves are quite sparse, and their are several major branches from the lower part of the tree (rather than one long, tall central trunk as is common in ponderosa and Jeffrey pine). The seed cones in this species are quite large and heavy with reflexed scale tips.

  • P. coulteri "coulter pine"
    This pine is not common in our area - it is more common in the Bay Area and southern CA. It is a three-needled pine with stiff green needles. The seed cones resemble those of foothill pine, but they are even bigger and can be really lethal if they land on you.

  • P. torreyana "Torrey pine"
    This is a rare 5-needled pine that grows in a restricted area of southern California and on Santa Rosa Island. This specimen was obtained from the arboretum.

  • P. attenuata "knobcone pine"
    This is a 3-needled, closed-cone pine. It isn't terribly common, but it has a wide distribution in California. The whorls of seed cones can remain on the tree for years.

  • P. radiata "Monterey pine"
    This species is planted widely in different areas of California (both as a street tree and in state and county parks). It is native to Point Lobos, south of Monterey. It is a 3-needled, closed cone pine with long spreading branches. The seed cones resemble those of knobcone pine, but the two species differ both in the size of the cone and the knobbiness of the ends of the cone scales.

  • P. contorta "lodgepole pine, Bolander pine, shore pine"
    This 2-needled species has several varieties, including the Bolander pine which is found in the pygmy forest in Mendocino County. The larger lodgepole pine is a very common component of mid- and upper-elevation pine forests in the Sierra Nevada and ranges all the way to the Rocky Mountains.

The following genera of Pinaceae do not have their needles grouped into bundles:

  • Abies "fir"
    Several of the species in this genus are found in upper elevation coniferous forests, however two are found in coastal forests.  The younger trees are rather distinctive, because the bark is so smooth.  The flattened leaves do not have decurrent leaf bases, and their attachment scar is smooth and round.  The leaves are often curved upward, so that it looks like they are just on the upper sides of the stems.  The seed cones are upright on the branches, and upon maturity, the cone scales fall off, leaving the upright cone axis on the stem.  The needles of most species are rather blunt-tipped, but Santa Lucia Fir (A. bracteata) is a distinctive rare species with huge sharp needles.

  • Picea "spruce"
    This genus is not all that common in California, although it is much more common in Oregon and Washington.  Look at the leaves on the demonstration material.  The leaf bases are decurrent on the stem, and when the needles fall off, they leave woody pegs where they were attached.  The needles are often well-distributed on all sides of the stem, but occasionally they are curved upward.  The needles tend to have rather pointy tips.  The seed cones, which hang down, have rather thin cone scales.

  • Tsuga "hemlock"
    Droopy trees with nodding tops. One species is found in northern California, especially in the coast ranges; the other species is found at high elevations in the Sierras. The flattened needles have leaf bases that leave woody pegs as in Picea, but the leaves are blunt tipped. The seed cones have delicate, thin scales and hang downward.

  • Pseudotsuga menziesii "Douglas-fir"
    One of two species in this genus in California. This species is very common in coniferous forest, both at the coast and in the Sierras. The buds are distinctive in being quite long and acute. When chewed, the needles have a citrus taste. The needles resemble those of Abies in being rather blunt at the tip, but the leaf bases are decurrent on the stem, and if you tear a needle off, it leaves an uneven leaf scar (not a smooth round one as in Abies). The seed cones are very distinctive, because of the long bracts that hang out of the cone scales.

 

Cupressaceae - We have 8 genera in this family in CA.  These are monoecious or dioecious trees and shrubs.  The leaves are scale-like, awl-like or linear, alternate, opposite, or whorled, and they often cover the branches.  The seed cones are woody or fleshy, and the scales are sometimes peltate.

  • Juniperus - "juniper"
    Shrubs or trees, sometimes of dry areas, usually with blunt awl-like leaves that lay close to the stem; sometimes the young growth bears very sharp needle-like leaves that curve away from the stem.  The leaves of subsequent pairs or whorls are similar, and the stems look cylindrical.  The seed cones are roundish with fleshy cone scales (“juniper berries”). Many species are dioecious.

  • Hesperocyparis
    A genus with a number of rare or uncommon species found in various plant communities throughout California. The leaves and stems resemble those of Juniperus, but the seed cones are round with woody, peltate cone scales (resembling soccer balls). Some species of this genus are closed-cone species that require fire for successful seed dispersal and germination.

  • Calocedrus decurrens - "incense cedar"
    A common species of the ponderosa pine belt. In this genus, the leaves of subsequent pairs are unequal in width, and the shape and arrangement of the leaves makes the stems look quite flattened. The scales of the seed cone are woody and elongated.

  • Thuja - "western red cedar, canoe cedar"
    More common in the Pacific Northwest, this species is found in northwestern California and the Klamath Range. The stems have the flattened look found in Calocedrus, but the scales are all about equal in shape. The cones are somewhat similar to those of Calocedrus, but the cone scales are wider and shorter.

  • Sequoia sempervirens - "coast redwood"
    This is one of the tallest species in the world (as well as one of the longest-lived). These majestic trees grow in alluvial soil in canyons near the coast (in the fog belt). The leaves are mostly flattened needles, but the stems (especially at the top of the trees) also bear scale leaves (you can find sprays of these stems on the ground beneath the tree). The branches grow in yearly segments that resemble compound leaves. To make things even more confusing, the trees shed branches, not leaves, reinforcing the impression that it has compound leaves. The seed cones are borne at the ends of the branches.

  • Sequoiadendron giganteum - "big tree"
    Another one of our special species, found in only a few places in the Sierra Nevada. The leaves are awl-shaped and alternate. The seed cones are much larger in this species than in Sequoia.

 

Taxaceae - A family with 5 genera worldwide, 2 of which are found in CA. The species are trees and shrubs. The California genera have alternate, flattened needles. The seed cone is highly modified so that the ovule is enveloped by a fleshy structure called an aril. The pollen cones have stamen-like structures bearing the pollen.

  • Taxus brevifolia "pacific yew"
    This small tree is found in forests in northern California. Sometimes, material of this native tree is unavailable, and we have a non-native cultivated shrub to examine. Note the flat needles.  The aril is often reddish.

  • Torreya californica "California nutmeg"
    This tree is found in shady canyons near the coast and in the Sierras.  It has huge flattened needles with pointy tips.  Measure the needles and find out how much bigger these leaves are than the other genera and species you need to know.  The aril on the seed cone on this species is quite large and greenish. The pollen cones have stamen-like structures.

 

Gnetales

Ephedraceae - A family with one genus.

  • Ephedra "mormon tea"
    In California, we have 7 species of Ephedra, all of which are dioecious shrubs of dry or desert communities. What color is the stem? ______________ Where are the leaves on this plant? ____________________ Are the leaves the major location of photosynthesis? __________________ What is the phyllotaxis? _______________ The cones are very reduced, the seed cones having 1 ovule in each of the upper bracts and a few sterile bracts below; the pollen cones have structures that resemble stamens in the upper bracts.

 

Lycopodiales

Lycophytes - club mosses, spikemosses, and quillworts
The extant taxa of this group are small plants, but many of their ancestors were large trees.  Their leaf-like structures have only one vascular bundle and are called microphylls; these sometime have an appendage on their upper (adaxial) surface called a ligule.  The sporangia bearing leaves are called sporophylls.  In the Jepson Manual, these leaf-like structures are just referred to as leaves (those bearing sporangia are called fertile leaves).

Lycopodiaceae - In CA, we have two genera in this family, each with one species.

  • Lycopodium clavatum  - "running pine"
    This species arises from a horizontal rhizome which produces upright stems.  One individual can form a large colony, forming rings of active growth, while the middle of the colony dies.  The phyllotaxis is alternate spiral, and the microphylls lack a ligule.  These are homosporous plants, with the sporangia occurring singly in the axils of the sporophylls.  The sporophylls are aggregated into definite cone-like structures (and appear quite different from the infertile microphylls).

 

Selaginellaceae - A family with one genus; in CA, we have 10 species.

  • Selaginella "spike moss"
    These are usually small, delicate plants in a mostly tropical genus; a few of the species specialize in dry habitats, such as "resurrection plant", which dries up into a ball in time of drought, and lies flat when moisture is available.  In California, usually the plants arise from a horizontal stem, which in some species gives rise to upright stems (in others just the horizontal stem is present).  The phyllotaxis is alternate spiral, but the microphylls are often 4-ranked and sometimes of different sizes depending on the rank to which they belong; ligules are present on the adaxial sides of microphylls.  All the species in this genus are heterosporous, with megasporangia and microsporangia borne singly in the axils of megasporophylls and microsporophylls; the sporophylls are grouped into definite cones, which may contain just one type of sporangium or both types.

 

Isoetaceae - A family with one genus; in CA, we have 6 species.

  • Isoetes - "quillwort"
    In this genus, the stem is a corm, which bears a dense tuft of linear microphylls, with broad overlapping bases and a ligule on the adaxial side.  Each microphyll is a potential sporophyll.  All species are heterosporous, which means that either a megasporangium or microsporangium can develop at the base of each microphyll.  The numbers of spores produced per sporangium is larger than in any other seedless vascular plant.  The sporangia are indehiscent - they disintegrate over the winter and release their spores.

 

Monilophytes

Equisetales

An order with one family.

Equisetaceae - A family with one genus; in CA, we have 5 species.

  • Equisetum - "horsetails"
    This may be one of the oldest extant genera, for it shows up very early in the fossil record.  The plants have lateral rhizomes, which produce vertical above-ground stems.  The stems are rough due to the deposition of silica, ribbed, and jointed (with obvious nodes and internodes).  The microphylls (referred to as "scale-like leaves" in the Jepson Manual) are borne at the nodes in whorls and are connate for part of their length, forming a sheath.  Sometimes there are linear branches present between the scale leaves (which are therefore whorled).  The homosporous sporangia are grouped into cones, with usually one cone terminating a vertical axis; in some species there are sterile, non-cone bearing vertical stems, as well as fertile, cone-bearing vertical stems, and these two types of stems may look very different from one another.  The cones consist of whorls of peltate structures called sporangiophores, each of which bears 5-10 sporangia.

 

Polypodiales

Leptosporangiate ferns
The taxa of this group have true leaves with a branched vascular system (not microphylls). The stems are usually rhizomes. Sometimes there are scales on the rhizomes that can be diagnostic. The leaves usually make up the major part of the plant body. The leaf diversity is amazing, and the branching patterns of the fern rachis and leaflets (pinnae) are equivalent to that of the angiosperm stem and leaves. Venation patterns on leaves and leaflets can be diagnostic. Sometimes one needs to look at the vascular bundle traces in the petioles to help decide between certain genera.
Most of the taxa of Leptosporangiate ferns are homosporous, except for some of the aquatics. The sporangia in these plants are not borne singly on leaves, but rather they are borne in groups called sori (singular = sorus), usually with many sori per leaf. The position of the sori - along veins, the midrib, or along the leaf edge - can be a diagnostic character. Sometimes the sori are covered with a flap of tissue called an indusium. The presence or absence of indusia can be diagnostic. If present, the shape of the indusium - peltate, cups, or attached one side - can be helpful in identification. Sometimes there are no indusia, but the margin of the leaf is inrolled so as to cover the sorus. This situation is known as a "false indusium".
The fertile or sporangia-bearing leaves or portions of leaves of some ferns are different in appearance from the sterile or non-sporangia-bearing leaves or portions of leaves. In such cases, the leaves are dimorphic (in The Jepson Manual, the language is "leaves of two kinds").
Most Leptosporangiate ferns have thin-walled sporangia that dehisce by a line of tissue called the annulus. This is a different type of sporangium than is found in the Eusporangiate ferns, such as the Ophioglossaceae; in that family, there are thick-walled sporangia.

Aquatic ferns

Azollaceae - A family with one genus. In California, we have 2 species.

  • Azolla "mosquito fern"
    These species are free-floating aquatics or stranded on mud. The plant body is small (1-5 cm long) and often fan-shaped; there are roots hanging from the stem forks. The plant body branches frequently and easily separates at branching points, producing clones. There are tiny leaves arranged alternately in 2 rows; these are sessile and often overlapping. Each leaf has 2 lobes, the upper floating or emergent and the lower submersed. All species are heterosporous, and the sporangia are borne in spore cases near the axils of the leaves. The microsporangia are many to a case; the megasporangia are just 1 per case.

 

Non-Aquatic ferns

Blechnaceae - In California, we have 2 genera in this family, with 1 species each. The genus Blechnum, "deer fern", is not available in lab, but it is interesting, because it has dimorphic leaves.

  • Woodwardia fimbriata "chain fern"
    This fern has very large leaves (1-2 meters long!) that arise from short, horizontal or erect, scaly rhizomes.  The leaves are once-pinnate and all alike, with each leaflet deeply pinnately lobed.  In this genus, the sporangia are in linear to oblong sori, which are parallel to the nearest leaflet midrib, and covered by indusia (the sori sometimes resemble chains of hot dogs).

 

Dennstaedtiaceae - In California, we have just 1 genus (with one species).

  • Pteridium aquilinum "bracken fern"
    This interesting species is found worldwide.  The leaves, which are all alike, arise from a horizontal, usually hairy rhizome. The petiole is strongly grooved on the upper side, and the leaf blade is generally 1-5 times pinnately compound.  The sporangia are borne at or near the margins of the leaflets and are covered by the inrolled edge of the leaflet (a false indusium).

 

Dryopteridaceae - In California, we have 3 genera in this family.  The leaves are tufted (several arising in one spot), and the rhizomes are short, suberect or erect, with large scales.  The leaves are all alike, with leaf blades that are 1-4 times pinnately compound.  The sporangia are borne in round sori which are situated along the veins; indusia of various shapes are present.

  • Dryopteris arguta "wood fern"
    This species is quite common in the Coast Ranges and the Sierra Nevada in open woods. The leaves are once- or twice-pinnate; if you look at a cross-section of a petiole, there are several vascular bundles arranged into an arc.  The sori are reniform (kidney) shaped and are the attachment is perpendicular to and on top of the veins of the leaflets. 

  • Polystichum "sword fern"
    This genus is very common, especially near the coast, in both coastal scrub and forests.  The leaves are once-pinnate, and each leaflet has a little lobe at its base.  The sori are round.

 

Woodsiaceae - We have 3 genera in California. As in Dryopteridaceae, the leaves are tufted. The rhizomes are again short but they may be creeping to erect, and the scales can be small to large. The leaves are 1-3 times pinnately compound.  The sori are round, oblong, or J-shaped, and indsuia may be absent or of various shapes.

  • Athyrium felix-femina "lady fern"
    This species is also common in the same habitats as wood fern and the two can be confused.  The leaf blade of this species is more delicate than that of wood fern; if you look at a cross-section of the petiole, there are two main crescent-shaped vascular bundles.  The sori are semi-circular to crescent-shaped and are attached along (parallel to) the veins of the leaflets.

 

Polypodiaceae - In California, we have one genus with 5 species.

  • Polypodium "polypody"
    These are common tufted ferns from short to long, horizontal, scaly rhizomes.  The leaves are all alike or the fertile ones may be larger than the sterile.  In California, the leaf blade is usually pinnatifid to once-pinnately compound.  The sporangia are borne in round to elongate sori in one row on either side of the midrib of the leaf. No indusia are present.

 

Pteridaceae - In California, we have 10 genera.  The leaves arise from horizontal to erect, scaly rhizomes.  The leaves usually all alike, rarely dimorphic.  The petioles are often wiry, thin, and of dark color.  The blade is generally pinnately compound or palmate and the segments pinnate.  The blade is often 2 or more times compound, with the segments of unusual shapes (round, fan-shaped, oblong).  The lower surface of blade often  has glands or powdery exudate.  The sporangia are borne  in sori or not, marginal, submarginal or along the veins; if marginal, they are sometimes covered by the inrolled edge of the leaflet margin (false indusia).  No true indusia are present.

  • Adiantum jordanii "California maiden hair fern"
    Note the fan-shaped leaflets and the color of the rachis and petiole in this interesting fern.  The sori are borne at the margins of the leaflets and are covered by the margin.

  • Adiantum aleuticum - "five finger fern"
    The leaves of this species are palmately compound, with the segments pinnately compound.

  • Pellaea andromedifolia - "coffee fern"
    Like maiden hair fern, this species also has interesting looking leaflets, false indusia, and a dark rachis and petiole.  How would you tell the two species apart? _________________

  • Pentagramma triangularis - "golden-back fern"
    You can make yellow fern prints with this species, because the back of the blade is covered with yellow powder.  The blades have a triangular shape overall and are 2-3 times pinnate.  The sporangia are not grouped into sori but are scattered throughout the back of the blade.

 

Ophioglossaceae - Eusporangiate ferns that differ from the leptosporangiate ferns in having thick-walled sporangia borne on leaf segments.  The fertile leaf segment bearing these sporangia (sporpophores) always looks quite different from the photosynthetic, sterile leaf segments (trophophores).

  • Botrychium - "grape-fern, moonwort"
    These beautiful ferns are often found at higher elevations.  Their leaves are relatively thick for ferns and have a very distinctive look to the leaflets.  Many species are becoming rare.

  • Ophioglossum - "adder's-tongue"
    Found in marshy areas; the spathe-like leaf segment is distinctive.

 

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