Showing posts with label Asters. Show all posts
Showing posts with label Asters. Show all posts

Thursday, January 25, 2018

Emilia fosbergii - Weeds I Like

Since I've been fulminating against weeds, I thought I'd mention some of the ones I like. One of them is Emilia fosbergii, or "Florida Tasselflower." Since there's no grass to compete against, it comes up everywhere in the yard, but it is easy to pull, so I leave it where I like it, and pull out the rest. (Or not. I am a lazy gardener).The ones that  haven't yet gone to seed go into the compost pot. Pollinators like it too.





The top and the bottom of Emilia sort of don't match. Tall, thin stalks end in delicate nodding, drooping, sometimes upright heads of rose-red disc flowers(more on this later). The anthers (pollen-bearing structures) and pollen are bright orange-yellow. The heads are around a half-inch long or a little more, depending on where the plant is growing, and about a quarter-inch wide at the base. The bottom of the plant on the other hand, is robust and vigorous.

Vigorous Bottom Portion of Plant


The stems and new leaves can be intensely hairy. Older leaves and "sepals" (phyllaries) show varying degrees of hairiness. The way the heads seem just to float above the foliage would make Emilia a nice plant to include in a mixed border. A larger plant with 8-10 flowering stems could even have the honor of a place in front, but since Tasselflower is a weed, its growth can be unpredictable. The flowering heads can be anywhere from 4 -to - 6 inches above the ground in young plants, up to around 20 inches above ground on older, larger plants. Growing conditions also affect the size and number of flowering stalks. The plants deteriorate after they set seeds. I haven't tried dead-heading to see whether I could prolong blooming, because the plant self-sows so vigorously.


The growth form of the plant is pretty cool. The first leaves on the stem are quite different from those farther along. They are roughly the shape of an inverted triangle on a long thin stem. The "stem" is actually not a petiole, but an extremely narrowed part of the leaf blade itself. As you move up the plant you get  intermediate leaf stages with increasingly shortened "stalks." The leaf itself becomes more oblong, and eventually arrow-shaped. At first glance it looks like the stem punches through the higher-up leaves, but a closer look shows that the base of the leaf clasps the stem.

Another leaf clasping a stem is formed between the "old" leaf and the main stem. This smaller leaf gradually enlarges to full size as the stem new itself grows longer. In the drawing below you can see the tiny leaf just to the right of the caption. The new stem elongates while the leaf enlarges, until you get the structure in the right hand of the drawing, in which the leaf and stem appear "on top" of the older leaf.





Another species, Emilia sonchifolia, "Lilac Tasselflower," occurs much less frequently in the yard. In general it seems a more diminutive and less vigorous plant, but that may be a function of its environment. The disk florets are a beautiful purple-pink instead of red. It is less common than its red cousin. According to the USDA Plants Database website, Emilia fosbergii occurs in Florida, Georgia, Louisiana, Texas and California. Its origin is unclear, with Asia, Australia, and South and Central America all listed as possibilities.


Emilia is a member of the Aster family. What many people (and I used to be among them) think of as a single flower in this family is actually a conglomeration, or composite, of individual flowers or florets, called a "head." This might seem like a trick the botanists have come up with to  keep us amateurs out, but it actually makes sense once you start really looking hard. The things that look like petals are "ray florets," and the things in the middle are "disk florets." The first drawing, on the left, shows the entire head, with ray florets around the outside, and the disk in the center. The drawing on the far right shows a cross section of the disk, with opened disk florets near the outside of the circle, and unopened disk flowers near the center. I gather, and I may be wrong, wrong, wrong, that in a case like the one illustrated, the ray florets are sterile, while the disk florets are fertile.



Pityopsis graminifolia
"Narrow leaf Silk Grass"





To make things more complicated, some members of the Aster family have only ray flowers. In this case they are fertile, and they are called ligulate florets. Ligulate florets have teeth. In the drawing of Hieracium megacephalon, "Hawkweed," below, there is no central disk, only ligulate florets. The sexual parts of the florets emerge from the base, so are clustered in the center of the head. Notice the teeth.

Hieracium megacephalon
Coastal Plain Hawkweed


And, there are members of the family with only disk florets, like Emilia, Ageratum, or thistles.

Circium, sp. "Thistle"



I find the seemingly infinite variety of ways in which plants go about their business utterly fascinating, and I keep discovering new things every time I look hard even at familiar plants.





Tuesday, November 14, 2017

Yes, South Florida Has Seasons!


People often lament that there are no seasons in Florida, especially South Florida. I’ll admit they are subtle, but they do exist. The big divide is wet vs. dry, but there are other changes as well. October is a transitional month - it may be wet, dry, or both. For us here on the coast, the rain faucet was turned off the second week of October, and I have used just about all of the rainwater I managed to save during the summer. Bright, breezy days dry plants out in a hurry.

It definitely gets noticeably cooler and drier after September. Though we can have hot and humid days all year, the relative humidity does drop in the fall, and it just doesn't "feel" like summer any more. We can turn off the air conditioning and open the windows again. What a liberation! Skies tend to be a more intense blue, as the summer haze disappears. 


 One of the first signs of autumn – the arrival of huge swarms of blackbirds and starlings - makes me very melancholy.  They swarm like something out of  Hitchcock, lining up on the power lines by the hundreds, or making sweeps of open lots and lawns. I could live with the blackbirds, because they are at least native, but I hate the destructiveness of the ever-increasing hordes of starlings. We have starlings all year,  but our summer numbers are augmented by northern migrants.

Another sign of autumn is the same as “up north.” The asters start blooming. The Elliott’s Asters in our front yard got so blown and burned by Irma that they may not bloom this year, but late summer and autumn definitely are glory time for many members of the Asteraceae
Aster elliottii - Elliott's Aster


Elliott's Aster is a diminutive plant, with heads no larger than a dime. You need a clump to have any garden impact, but that is not hard given the plant's suckering habit. In fact, unless you have room to spare, you will be pulling out plants regularly to keep it within bounds. The plant occurs naturally in swampy or marshy places. It grows in a lower area of my garden, which stays more moist than the rest, but is scarcely swampy unless we have a particularly wet summer. During the winter, when we get little rain, it may go dormant and disappear entirely, the way northern perennials do to survive cold weather. In spite of its eagerness to take over the garden, it really is a charming plant, and various pollinators love it.

Autumn is the time Florida's beautiful native grasses come into bloom.

 The chalky-silver/blue-green blades of Elliott's Lovegrass, Eragrostis elliottii, make it lovely even out of bloom. In late summer to early fall it sends up hundreds of tall, delicate, multi-branched bloom stalks that first bear tiny flowers, and later multiple seed heads (spikelets). In full bloom the plant seems to be covered with a fine white or golden-beige mist. I don't water it, so it turns brown, and may even disappear during winter. Maybe this year I will water one clump to see whether the foliage will persist. It will make a clump about 2-3 feet wide and tall. My only complaint with this plant is that its brittle seed stalks break off and tumble in the wind. They always want to blow in the door when I go in and out, and they have the very irritating habit of working their way up my pants leg. It's impossible to fish them out without taking my trousers off. A real nuisance! But worth it.




The blooms of Pink Muhly Grass, Muhlenbergia capillaris, are even more delicate and diffuse than those of Elliott's Love grass. Muhly grass comes into bloom a little later, though the showy times overlap. Muhly grass is one of our most beautiful native grasses. It likes seasonal moisture with  a winter dry-down, so it is perfect for my yard. It has a more vase-like form than Elliott's love grass, and also grows taller.

The rising or setting sun shining through the flowers gives a golden sheen to their  pink/purple coloration - one of the many beautiful sights provided by Florida native plants.

Fall  is mating time for the ospreys. Their melodic, piercing chirps and squeals mark the early mornings and early evenings. They are in the sky a lot, performing their aerial displays. This year the ospreys have more work than usual, since many of their nests were destroyed when Hurricane Irma toppled trees, power poles, and channel markers.

Migratory birds start arriving, Palm Warblers being among the first.

 To quote  Morton C. Winsberg, Florida Weather. (University of Central Florida Press, 1990, page 26): "{Those} who find Florida's climate monotonous ...might learn to use criteria other than temperature to differentiate one season from another." There are lots of signs that summer is over - we just have to get outside and look around us.

Carphephorus corymbosus (Chaffhead) - A Florida Native Plant in the Aster Family