lab manual

 

<< Lab 7 Monocots: Alismatales (Araceae); Liliales (Liliaceae); Asparagales (Agavaceae, Alliaceae, Themidaceae, Iridaceae, Orchidaceae) >>

 

Alismatales

Araceae - A mostly tropical family, with 7 genera that contain species native and/or naturalized in California. Most members of the family are characterized by an unusual inflorescence in which the unisexual flowers are borne in a tight spike called a spadix, which is subtended and surrounded by a large bract called a spathe. However, in the duckweeds and relatives (genera Lemna, Wolffia, and Wolffiella), which are floating aquatics that form dense clonal populations on bodies of fresh water, the inflorescences and flowers, which are rarely seen, are extremely reduced, as are the vegetative bodies. There is no differentiation between leaves and stems, and Wolffia and Wolffiella lack roots as well.

  • Zantedeschia aethiopica - "calla lily" This species is a native of South Africa, but it is found naturalized here and there in coastal California, often near old homesteads. Look at the spadix and spathe. Where on the spadix are the pistillate and staminate flowers borne? _____________________________

  • Lemna - "duckweed" Small flattened, elliptic plant bodies, greenish or reddish in color. New bodies are made through budding.

 

Members of the following two orders are primarily perennial herbs that persist from year to year via underground storage organs (bulbs, corms, rhizomes). The flowers generally have six tepals (“perianth parts” in the Jepson Manual) in two whorls of three, all of which are petal-like in color and texture, but in some cases the two whorls are different in size and/or shape, and then the parts of the outer whorl are referred to as sepals and those of the inner whorl as petals.

Liliales

In this order, the tepals are often spotted.

Liliaceae

  • Calochortus "fairy lantern, mariposa lily"
    Native perennial herbs, arising from bulbs, with lanceolate basal and/or cauline leaves. The perianth may be closed into a sphere or opened widely. There are 3 sepals and 3 petals, all free of one another. Each petal has a nectary at its base and there are usually hairs on the inner surface of the petal as well.

 

Asparagales

Agavaceae - a diverse family, including shrub- and tree-like forms with thick, rigid leaves (Agave, Hesperoyucca, and Yucca), as well as perennial herbs with thin leaves (e.g., Camassia, Chlorogalum).

  • Chlorogalum pomeridianum "soap plant"
    Native perennial herbs with long wavy basal leaves that arise from a bulb covered with fibrous leaf bases. The inflorescence is a tall panicle of white flowers. Each flower opens for one day only. It is called soap plant because of the saponins contained in the bulb - just add water and lather up!

  • Hesperoyucca/Yucca "our lord's candle, Joshua tree"
    Subshrubs to trees with stiff, sword-like, leaves that grow in dry habitats, especially deserts. Joshua tree (Yucca brevifolia) can be a dominant tree in some parts of the Mojave Desert. The inflorescence is a panicle. The flowers have six large, waxy tepals. In some species of Hesperoyucca, the plant dies after flowering. Members of these genera have specialist moth pollinators that visit the flowers, roll the pollen into little balls and carry the balls to another plant, where they pack the pollen balls onto the stigmas of the flowers. After this, the moths deposit their eggs inside the ovary of the pollinated flower. When the moth larvae hatch inside the ovary, they eat a certain proportion of the seeds of the developing fruit, leaving plenty of other seeds to mature.

 

Alliaceae - perennial herbs, generally with an onion odor, with the flowers in scapose umbels (occasionally reduced to just one flower) subtended by bracts.

  • Allium "onion"
    Native perennial herbs, arising from bulbs, with 1-5 linear basal leaves. The patterns of cell sculpture on the layers of the bulb coat are important in the identification of the species. Note that although there are bracts subtending the umbel inflorescence, the pedicels within the umbel lack individual bracts. All species have a characteristic onion odor, when fresh.

 

Themidaceae - perennial herbs with the flowers in scapose heads or umbels, with bractlets subtending the individual flowers as well as bracts subtending the entire inflorescence. In most of the genera, the tepals are connate at the base into a tube. The genera and species differ in stamen number, placement of staminodes, and other small details.

  • Dichelostemma "blue dicks, ookow"
    Common native perennial herbs, arising from corms, with several linear basal leaves. The inflorescence type is a ________________. Note the papery bracts subtending the inflorescence. In addition, each pedicel within the inflorescence is subtended by a bract. Is the corolla made up of petals and sepals or are there tepals? _______________ How many fertile stamens are there in the flowers of Dichelostemma capitatum? _____ Are all the stamens alike? Contrast this with the stamen number in Dichelostemma volubile. ____________________ Notice the crown of appendages surrounding the stamens and how the peduncle is somewhat twisted.

  • Triteleia "Ithuriel's spear, brodiaea, triteleia"
    Common native perennial herbs, arising from corms, with several linear/lanceolate basal leaves. The inflorescence type is a __________________. The bracts subtending and within the inflorescence are similar to those in Dichelostemma. The perianth is similar to that of Dichelostemma, but how many fertile stamens are there in each flower? _____

  • Brodiaea
    This genus is not as common as the previous two. The species of this genus can look similar to Dichelostemma or Triteleia but there are white flaps alternating with the stamens (staminodes). How many fertile stamens are there? _______

 

Iridaceae - Perennial herbs with 2-ranked, equitant leaves (the leaves are sharply folded along the midrib, which gives the appearance that the blades face sideways and are all arranged in the same plane). The flowers are variable in appearance and symmetry – all of our native species (in three genera) have radially symmetrical flowers, but some species in the naturalized genera have bilateral flowers. All species have flowers with inferior ovaries.

  • Iris
    A native genus of perennial herbs that arise from rhizomes. The flowers have 3 showy colored sepals, 3 smaller petals, and 3 petaloid styles that arch over the 3 stamens. Where are the stigmas? ____________________________ There is a hypanthium tube that can be quite well-developed (long) above the ovary.

  • Sisyrinchium bellum "blue-eyed grass"
    A native genus of perennial herbs that arise from rhizomes. The equitant leaves are grass-like. The flowers are very different from those of Iris. There are 6 tepals which are usually free. The 3 stamens may be free of the perianth or adnate to it. The flowers are very short-lived, opening in the morning and closing by evening.

 

Orchidaceae - An extremely large family (the largest family of angiosperms) with about 800 genera and 25,000 species worldwide.  In the tropics, these plants can be epiphytic, but in California, we have only 11 genera, all terrestrial. Many of the species are uncommon, due to either their biology, overcollecting by people, or herbivory (deer).
All orchids are highly dependent on a mycorrhizal fungal associate which aids in the absorption of nutrients from the soil. The fungal association begins as soon as the seeds germinate (the seeds are dispersed with the fungal spores). In fact, the seeds are so small, they contain no nutrients for the developing seedling. Some orchids (such as our "phantom orchid" - Cephalanthera austiniae) lack chlorophyll, and are dependent on the fungus for all their nutrition at all stages of their life-cycle.
The family is characterized by its unusual flowers which are very specialized (they have very specific pollinators). Refer to the Powerpoint lecture slides for illustrations of the following floral parts (Orchid floral structure). The perianth has 3 sepals and 3 petals with the lower petal developed into a lip, sometimes with several lobes. The stamens, style, and stigma are all adnate to a structure called a column. Usually, there is only 1 stamen (sometimes 2), and the anther is a compartment with a lid; inside the compartment, there are pollinia (packages of pollen). The stigma cavity is below the anther compartment and there are 2 receptive lobes where the pollinia from another flower can be deposited.

  • Epipactis gigantea "stream orchid"
    A rather unshowy orchid with greenish flowers that grows in moist places throughout California. Find the anther chamber (with its pollinia) and stigma chamber. Is the ovary inferior or superior? ___________

 

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