Members of the Asterid II clade have the typical Asterid floral formula, with the notable exceptions that, in Apiales, the petals are free at maturity and the stamens are free from them. In most members of the Asterid II clade, including all of the ones we cover in this course, the ovary is inferior.
Apiaceae - This is yet another family with an alternate name - Umbelliferae. It is an extremely important family, providing many common cooking herbs (coriander, parsley, cilantro, anise) as well as vegetables (carrots, parsnips). In California, the species of this family are mostly herbs (some quite large) with distinctive enlarged leaf bases, lobed or compound leaf blades, and flowers arranged in umbels or heads. There are 40 genera in California, and some of them are quite difficult to key - the species distinguished by minute or variable characters. Fruit characteristics are emphasized in both the key to genera and the keys within individual genera; therefore, it is important to try to collect specimens of this family that have a range of maturity within the inflorescence, with some fresh flowers and some developing fruits. Without fruits, it may be impossible to key the specimen to species.
Heracleumlanatum "cow parsnip"
A large herb of moist places (drainages). The big leaves are palmately lobed or compound; look at the large leaf bases. The inflorescence is a compound umbel of white flowers. Look carefully at the flowers; is the ovary inferior or superior? ______________
What is the symmetry of the flowers? __________ Is this plant glabrous or tomentose? _________________
Conium maculatum "poison hemlock"
A non-native that is quite poisonous when eaten. This is the species that killed Socrates (given to him as a form of capital punishment). Note the highly dissected leaves, with serrated leaflets, and splotches of purple on the stem. The flowers are white.
Other genera that we may have on display:
Unusual looking Apiaceae with spiny bracts and leaves. The flowers are arranged into dense heads which may be arrayed in cymes. A number of these species are vernal pool endemics and are rare. The juvenile leaves of the pool plants are tubular and hollow, reaching to the top of the pool and allowing oxygen to enter the plant. As the pool dries, the adult leaves develop.
A common large non-native with highly dissected leaves with the odor of anise. The flowers are yellow.
A genus of small perennial herbs with winged fruits that are difficult to key! A number of species are uncommon serpentine endemics.
Rather common herbs with strong-smelling leaves (like celery but stronger). The flowers, which may be either staminate or bisexual, are arranged in dense heads and the corollas can be yellow or purple. The fruits are covered with prickles.
Daucus "wild carrot; Queen Anne's lace"
We have both a native and in introduced species in this genus, and they don't look much alike. Daucus pusillus is our hairy, unshowy native, while D. carota (Queen Anne's lace) is a common non-native. Look at the umbel of flowers in the latter species; are the corollas all the same color? _________________________
Plants with opposite leaves.
Adoxaceae - Represented in California by two genera of shrubs, Viburnum and Sambucus, each with 2 native species. The flowers are radially symmetric with rotate (open, spreading, wheel- or saucer-shaped) and each is quite small, but in both genera in CA they are aggregated into large showy inflorescences. The leaves in Viburnum are simple while those in Sambucus are pinnately compound.
Sambucus - "elderberry"
Small trees or shrubs with opposite, pinnately compound leaves. The leaflets are serrated. The white flowers are small, but they are arranged into large terminal panicles.
Caprifoliaceae - Another family with just two genera in California, though sometimes treated more broadly to include Adoxaceae, as in the first edition of The Jepson Manual. Shrubs and vines whose flowers may be radially or bilaterally symmetric.
These are shrubs or twining vines, often deciduous. The leaves are mostly entire; sometimes the leaves just below the flowers are fused around the stem. The corolla has a well-developed cylindrical tube and the limb may be radial, but it is often bilateral (two-lipped). At the base of the corolla, there may be a swelling (pouch) on one side.
Shrubs with simple, sometimes shallowly lobed, deciduous leaves. The corolla is bell- or funnel-shaped with a short tube and radial symmetry. The mature fruits are white.
Members of this order have an interesting pollen presentation method called a "plunger mechanism." In this arrangement, when a flower opens, the stamens are partly or fully connate around the style, and the style has not yet grown to its fully mature height. Within an individual flower, the anthers shed pollen into the staminal tube, before the stigma unfolds. After the pollen is shed, the style then begins to elongate to its mature height, with the non-receptive (closed) stigma pushing the pollen out the top of the staminal tube. Pollinators can then take the pollen from the top of the tube. After this procedure is complete, the stigma finally opens and is receptive, awaiting pollen from a different flower.
Campanulaceae - In California, the members of this family are herbs, usually with alternate, simple leaves and showy flowers. The key in the Jepson Manual separates most of the genera in the family into two subfamilies: Campanuloideae, with radially symmetric corollas and free stamens, and Lobeloideae, with bilaterally symmetric, bilabiate corollas and the stamens, including the filaments and the anthers, fused into a tube. A third subfamily, Nemacladoideae, with bilaterally or radially symmetric flowers and partly fused filaments, is represented by just one genus (Nemacladus).
A genus of small, glabrous, annual herbs that are common in vernal pools. The symmetry of the corolla is _______________. An interesting feature of the flowers of this species is that the corolla becomes inverted (upside-down) during its development, so that the large lower lip was actually the upper lip, when the corolla began to develop.
We will also have a representative of Campanuloideae - e.g. Campanula - for you to examine.
Asteraceae - Yet another family with an alternate name - Compositae. This is the largest family of eudicots in the world (and the second largest family of angiosperms, after Orchidaceae) as well as the largest family of vascular plants in California, with 239 genera, including many native and introduced species. It is very important economically, providing seeds and oils (ex. sunflower), herbs (chamomile, feverfew, etc.), and vegetables (artichokes, lettuce, dandelion greens, etc.). The structure of the inflorescence of this family is more complicated than in other families, and specialized terminology has been developed to deal with it. Your T.A. will guide you through the dissection of several different genera, so that you will get a feel for the variation in structure and associated terminology.
Important terms used in the Jepson Manual (refer to lecture slides for illustrations of terms):
Head: The type of inflorescence found in the Asteraceae.
Receptacle: In the Asteraceae this term usually refers to the large area in the head to which all the flowers are attached. In addition, each individual flower has its own receptacle, which is the area to which all the flower parts are attached.
Phyllary/involucre: The bracts subtending/surrounding the head of flowers. Each bract is called a phyllary; together, all the phyllaries make up the involucre.
Series of phyllaries: This refers to the number of whorls of phyllaries that are present in the involucre. Sometimes there is just one series (i.e. one whorl), other times there is more than one series. In the latter case, the phyllaries are often graduated (the inner phyllaries are longer than the outer - another term for this is imbricated).
Palea(e): A scale-like bract subtending an individual flower on the receptacle. If present, the head is said to be paleate; if absent, epaleate. In the tarweeds (e.g, Layia, Madia), paleae are present only in a ring between the ray and the disk flowers. Some heads that lack paleae have long hair-like bristles among the flowers (“heads bristly”)/ Heads that have neither paleae nor long bristles may nonetheless have minute scales or short hairs among the flowers, or their receptacles may be glabrous.
Disk flower: A flower type that is usually radially symmetric, with 5 equal lobes; sometimes several lobes are longer than the others (ex. in Cirsium). Disk flowers are usually bisexual, but sometimes they are staminate.
2-lipped flower: This type of flower, rare in the California Asteraceae, has one very long lip and one short lip.
Ligulate flower: A bisexual flower with a ligule, the tip of which has 5 small dentations.
Ligule: A much elongated, strap-shaped corolla limb on a ligulate flower of the Asteraceae (in the Poaceae, the term “ligule” has a very different meaning).
Ray flower: A flower found at the margin of a radiate head, with a strap-shaped corolla limb that usually has 3 small dentations. Ray flowers are either pistillate or neuter.
Ray: A much elongated, strap-shaped corolla limb on a ray flower of the Asteraceae.
Filiform flower: A flower that resembles a disk flower but either lacks lobes (it just consists of a tube), has very reduced lobes, or has a vestigial liguleFiliform flowers are either pistillate or neuter.
Discoid head: A head made up only of disk flowers; usually all of the flowers are perfect, but sometimes they are just staminate.
Radiant head: A discoid head in which the outermost flowers have much enlarged, often bilateral corollas, giving an appearance similar to a radiate head.
Liguliferous head: A head made up only of ligulate flowers, all of which are perfect.
Radiate head: A head that is made up of disk flowers in the center and ray flowers around the outer edge. The ray flowers are either pistillate or sterile. The disk flowers are usually bisexual.
Disciform head: A head that contains pistillate or sterile flowers with inconspicuous or no corollas (filiform flowers); it may or may not contain bisexual or staminate disk flowers as well.
Unisexual head: A head that contains only staminate or only pistillate flowers; if pistillate, the flowers are filiform, as in disciform heads. Species bearing unisexual heads may be monoecious or dioecious. Species with disciform and/or unisexual heads are found under group 2 in The Jepson Manual second edition.
Pappus: The modified calyx of an Asteraceae flower. The calyx may be missing (no pappus present) or be modified into bristles, awns, or scales.
Achene: The fruit type of the Asteraceae (derived from the inferior ovary). A more specific name for this fruit type is a cypsela, which is an achene to which the calyx remains attached.
You will dissect the following plants with your TA. Fill out the appropriate blanks:
Eriophyllum lanatum "woolly sunflower"
A very common subshrub with woolly pubescence, present in many plant communities throughout California.
Number of phyllary series: ________ What types of flowers are present? _____________________
Head type: _________________
Are paleae or bristles present on the receptacle? ________________
What type of pappus is found on the achenes? _______
What color are the most mature achenes? _______
Where are the most mature achenes located in the head? _________
Dissect one of the maturing achenes; how many seeds are inside the achene? ____________________ Group # ______
A genus of shrubs of drier scrub communities in various parts of California, especially southern California.
Number of phyllary series: ________
What types of flowers are present? _____________________ Head type: _______________________________
Are paleae or bristles present on the receptacle? ____________
If so, where are they located in the head? ____________________________________
What type of pappus is found on the achenes? ______________________
Are the achenes hairy? ___________
Where are the hairs located on the achenes? __________________________________
Are all of the ovaries developing into achenes? _____________________________________ Group # ________
Matricaria discoidea "pineapple weed" - A very common, non-native annual herb.
Number of phyllary series: __________
Are the series of equal length? _______________________
What types of flowers are present? _____________________________
Head type: ___________
Are paleae or bristles present on the receptacle? _______________
Is there pappus on the achenes? _______________________
Are all of the ovaries developing into achenes? __________ Group # ___________
Leontodon (or related substitute such as Hypochaeris, Taraxacum or Sonchus)
Number of phyllary series: __________
Are the series alike? ____________________________
What types of flowers are present? ___________________________
Head type: _______________
Are paleae or bristles present on the receptacle? _________________
What type of pappus is found on the achenes? ___________
Tear off part of the plant. What color is the sap? _________________ Group # ____________
Baccharis salicifolia "mule fat"
Number of phyllary series: __________ Are the series alike? ____________________________ Are the flowers (1, 2) bisexual? __________________ What types of flowers are present? _______________ Head type: _______________ Are paleae or bristles present on the receptacle? _________________ What type of pappus is found on the achenes? ___________ Group # ______________
You are now ready to key out today's unknowns and examine the rest of the lab material.
The following additional genera of Asteraceae may be on display. Some you have already dissected:
Common herb with aromatic, dissected foliage and white flowers.
Non-native herbs, sometimes with bitter scent, dissected or lobed foliage, white ray flowers. Are paleae or bristles present on the receptacle in the heads? _______
Artemisia "sagebrush, mugwort"
Aromatic herbs and shrubs, sometimes medicinal. California sagebrush (A. californica) is an important component of many scrub or chaparral communities. The alternate leaves are usually lobed or dissected. The heads are either discoid or disciform.
Baccharis "coyote brush, mule fat"
Native shrubs. There are two local species. Coyote brush (Baccharis pilularis) is the more common plant and is an important dominant in our scrub and chaparral communities (we may or may not have this species to examine - it flowers in the fall). The second species, mule fat (Baccharis salicifolia), which is in flower now, is common along watercourses. All the species of this genus are dioecious and lack ray flowers. Given that piece of information - what types of heads would you expect these species to have? ____________________
Our common C. intybus is a roadside weed with blue flowers that wither quickly.
Cirsium / Carduus / Centauria / Silybum "thistles"
Prickly herbs with stiff, sharp phyllaries. We have both native and non-native species of Cirsium, but only non-native species of the other three genera.
Cotula coronopifolia "brass buttons"
A very cute non-native, common in wet areas, especially near the coast. Look at the heads - are there ray flowers present? What type of heads are these? __________________
Shrubs of drier habitats, the leaves often drought deciduous. The flowers are yellow.
Herbs and subshrubs with colorful rays (often white, pink, purple) and yellow disk flowers. The pappus is of fine bristles.
Eriophyllum "woolly sunflower"
Low, rather hairy herbs or subshrubs with yellow flowers.
These are native herbs and shrubs that are found in a range of habitats. Notice the phyllaries in this plant - what is distinctive about them? ___________________ ____________________ Touch the heads - how do they feel? __________________________
Showy natives with large yellow ray flowers and elongated basal leaves.
Mostly native species, a few non-native. Feel the leaves and stems - what sort of hairs are on the surface - what does it feel like? _________________
Lasthenia "gold fields"
Annual herbs with opposite leaves and yellow flowers. How many series of phyllaries are there in this species? _________________
Layia / Madia "tarweed, tidy-tips"
Interesting, often strong-scented plants, with glandular hairs. The paleae in these plants are present between the ray flowers and the disk flowers in one whorl. Look at the phyllaries - each phyllary is wrapped around the ovary of a ray flower (1, 2).
Senecio "butterweed", "groundsel"
Herbs or shrubs, usually with yellow flowers; the involucre is often made up of just one series of equal phyllaries (sometimes there are two series, each equal, or the main phyllaries are subtended by much shorter bracts).
Taraxacum / Leontodon / Hypochaeris "dandelion", "hawksbeard", "cat's ear"
What is the leaf arrangement in this introduced weed? _____________ What is the head type? ____________________ How do the achenes get dispersed? _________
Wyethia "mule ears"
Large herbs with large basal leaves and big radiate heads with yellow rays.