Fall Fliers

 

Fall-blooming Blue Mistflower and White Boneset attract late season butterflies.

Butterflies are frequently thought of as insects that fly primarily in the spring and summer seasons.  This is because the emergence of many butterfly species is unimodal, which means that their numbers increase as environmental resources increase.  These resources are defined as their host plants and nectar plants, which also become available during these warmer seasons.  

However, there are some species that have bimodal emergences, or increases in numbers in both the spring/summer and fall seasons.  It is thought that the division of offspring between two different emergence times may have evolved to avoid producing all offspring at one time.  This approach would reduce the risk of species mortality in case of potential fluctuations in habitat quality. 

Whether they be unimodal or bimodal, butterfly species typically exhibit a tightly synchronized adult emergence in order to help them locate mates. Further still, some species are present in low numbers during most of the year, but their numbers increase during the fall.  In central Texas these species include the Tailed Orange (Pyrisitia proterpia), Julia (Dryas iulia), Common Mestra (Mestra amymone), Queen (Danaus gilippus), and White-striped Longtail (Chioides albofasciatus).

In the fall, the Tailed Orange is in its winter form, yellow with brown lines and blotches below and a noticeably pointed hindwing edge.  Its summer form is unmarked yellow below and the hindwing edge is less pointed. It flies late summer through fall, and uses senna species as its host plant.

Tailed Orange, winter form

The fast-flying Julia is mostly orange above and orange to brown below, with the female being a duller orange than the male and having a dark forewing band.  Its longwing shape is quite distinctive and it prefers woodland edges and gardens where it uses passionvine species as its host plant.

Julia, male

A slower, flat-winged flyer, the Common Mestra is pearly white above with a pale orange border on its hindwing, and mostly pale orange below with a thin, white spotband.  It is most often seen from June to November, and it uses noseburn species as its host plant.

Common Mestra

The Queen butterfly is often confused with monarchs, as it also uses milkweed species as its host plant.  Rich dark brown to deep orange above with white spots in the black wing margins, it lacks the strong black veining on the wings like monarchs, and can be found in any open habitat usually visiting flowers.

Queen

Straying into our area from south Texas, the White-striped Longtail is a dark brown butterfly with very long tails, and a prominent white stripe on the underside of its hindwing.  It usually perches with its wings closed, and uses various legume species as host plants.

White-striped Longtail

One way to increase your chances of seeing these fall fliers in your yard is to provide native plant species that bloom in late summer and well into fall. These plants include Frostweed, Gregg’s Mistflower, Blue Mistflower, White Boneset, Lindheimer’s Senna, Plateau Goldeneye, and Texas Lantana.  And remember, fall is the perfect time to plant!

Glorious Goldeneye

 

Plateau Goldeneye

From late September to November our roadsides, woodland edges, and meadows are brimming with the profuse yellow blooms of Plateau Goldeneye (Viguiera dentata).  Also called Toothleaf Goldeneye and Sunflower Goldeneye, this native plant is extremely drought tolerant, prefers well drained soils, and grows up to 3 feet in full sun and to 6 feet in partial shade.  It can be found throughout central and west Texas, and into New Mexico, Arizona, and Mexico.

Blooms appear at the tips of long, branched stalks

Plateau Goldeneye is a bushy, much-branched plant that tends to grow in colonies.  The yellow daisy-like flowers are numerous, 1.5 inches wide, and appear at the tips of long, slender, leafless stalks.  These composite flowers have a button-like central cluster of fifty or more tiny yellow disk flowers surrounded by 10 to 14 golden yellow ray flowers with notched tips and nearly parallel veins. 

Each ray flower (petal) has a notched tip and somewhat parallel veins

The green leaves of Plateau Goldeneye are triangular with a broad base, tapering to a point, and toothed or serrated along the edges.  They can vary from 1 to 6 inches in length, and can be attached to the stem in either alternately (near the base) or oppositely (toward the tip). As fall approaches, their typical rich green color turns more of a gray-green, and the plant starts to develop flower buds around September.   

Leaves have roughly serrated or toothed edges

Throughout its growing season, Plateau Goldeneye attracts many types of pollinators, especially bees, and is one of the preferred host plants for the Bordered Patch butterfly. In fall and winter, spent flower heads provide good forage for Lesser Goldfinches and other seed-eating birds, as each flower produces numerous achenes, or small, dry single-seeded fruits that do not open to release the seed.  If left to its own devices, Plateau Goldeneye reseeds readily under favorable conditions, but it is easy to manage.

Bordered Patch

Lesser Goldfinch

The Aztec/Nahuatl people called this plant Chimalacate, and in several Mexican states infusions of Plateau Goldeneye are used as an antibacterial treatment for baby rash.  A pharmaceutical study in 2008 confirmed that a compound extracted from this plant does indeed show antifungal properties. Plateau Goldeneye is in the genus Viguiera in the Aster family, and is named in honor of the 19th century French botanist and physician Louis Guillaume Alexandre Viguier.  Regardless of this plant’s history, enjoy the glorious blooms it provides us in the fall, along the roads and trails of central Texas!

Whorled Wonders

Great Plains Ladies Tresses

The spiral, which is a fundamental form in nature, is most splendidly illustrated in a genus of wild, native orchids called Spiranthes.  Commonly known as ladies tresses, the genus name comes from the Greek speira meaning ‘coil’ and anthos meaning ‘flower’, and refers to each species spirally arranged inflorescence.  The most predominant species of orchid found in Texas prairies, several members of this genus are colonizers of sparsely vegetated areas, appearing on newly disturbed sites such as roadsides and cleared fields, increasing in number until outcompeted by other vegetation.

Of the 15 native Spiranthes species in Texas, several are so similar in appearance that either a hand lens or microscope is often needed to distinguish one from another. To add to the confusion, many closely related species are also known to hybridize. However, Central Texas, the most common include the Great Plains Ladies Tresses (S. magnicamporum) and the Nodding Ladies Tresses (S. cernua).  

Great Plains Ladies Tresses has 2 to 4 narrow, grass-like basal leaves, up to 6 inches long, that are usually absent or withering during the flowering period.  The flower spike can range from 4 to 24 inches tall, and is made up of 12 to 54 small white tubular fragrant flowers, tightly or loosely spiraled, that nod abruptly from the base.  Blooming from September to November, it prefers calcareous grassland habitat, often growing in association with our native Seep Muhly.  In wet years, this orchid may appear in robust spikes numbering in the hundreds, and in dry years it may not flower at all.

Nodding Ladies Tresses has 3 to 5 narrow, grass-like, basal leaves, 8 to 10 inches long, and are typically present at flowering.  It has a flower spike that can grow from 4 to 19 inches tall, and consists of 10 to 50 small white tubular flowers, tightly or loosely whorled in 2 to 4 rows along the upper portion of the stem.  Blooming from late September through November (and sometimes even into December), it can grow on wet or dry sites, but prefers more acidic, sandy soils.

Flowers of Spiranthes orchids begin opening at the bottom of the inflorescence.

Like most orchids, the flowers of these Spiranthes species are resupinate, or twisting during development into an upside-down position.  In fact, the tendency of the flowers to droop slightly gives the Nodding Ladies Tresses both its common and species name, for cernua comes from the Latin and means ‘drooping.’  Unlike other closely related species, the flowers of the Nodding Ladies Tresses have little or no fragrance, but like other closely related species, the flowers are pollinated by bumblebees.  As with most Spiranthes, bumblebees start at the bottom and move upward on the inflorescence in search of nectar. Older flowers at the base of the flower stalk have more nectar, which makes them an efficient first stop for the foraging bumblebees.

As mentioned above, many Spiranthes are difficult to identify to species, and both the Great Plains Ladies Tresses and the Nodding Ladies Tresses are no exceptions.  In fact, Nodding Ladies Tresses is known as a compilospecies, which is defined as a genetically aggressive species that incorporates the heredities of a closely related species by hybridization through unidirectional gene flow, and may even completely subsume that species over time.  Now that’s a whorled wonder!

Astonishing Acorns

Texas Red Oak is one of many types of oaks that produce
acorns in autumn

Famous for its oak trees, there are more than 50 species of oak native to Texas.  In our region of Central Texas, some of the most common include Live Oak (Quercus virginiana), Texas Red Oak (Quercus buckleyi), and Bur Oak (Quercus macrocarpa).  

A familiar tree with a stately growth habit, Live Oak is commonly 50 feet tall but with several large, twisting limbs that form a low, dense crown that can spread over 100 feet.  Its leaves are oblong in shape, leathery, 2 to 4 inches long and 0.5 to 2 inches wide.  Slow-growing but long-lived, it appears to be evergreen rather than deciduous since its old leaves fall just as new leaves emerge in the spring.  The annual acorns of this tree are dark brown and shiny, about 1 inch long and 0.5 inch wide, half covered in a gray, downy cup borne on a long stem. 

Live Oak Acorns

Texas Red Oak, also called Spanish Oak or Buckley Oak, is a small to medium tree to 35 to 70 feet tall, and its habitat is restricted to limestone ridges, slopes, and creek bottoms.  Its leaves are deeply lobed and it provides good shade in the summer and deep red color in the fall.  Its acorns are biennial, or maturing every other year, but when they do occur they are plentiful.  They can occur singly or in pairs, are up to 0.75 inches long and 0.5 inches wide often streaked with dark lines, and set in a shallow cup covering one-third to one-half of the fruit.

Texas Red Oak Acorns

A large, deciduous tree reaching a height of 80 feet or more, the Bur Oak has heavy branches that form an open, spreading crown, and leaves with highly variable lobes that can grow to 12 inches long and 6 inches wide.  But what is most characteristic is its’ distinctively large annual acorns, up to 2 inches long, set into a deep mossy-fringed cup that gives this species its common name.  In fact, an alternate common name is Mossycup Oak.  Bur Oaks have a medium growth rate, and develop a deep taproot that allows them to draw water and anchor the tree, even in drought conditions.

Bur Oak Acorn

The origin of the word acorn is dubious, as several sources are possible including Old Norse akarn meaning ‘fruit of wild trees’, Gothic akran meaning ‘fruit’, and Old English aecern meaning ‘mast or oak-mast.’  Mast is a term often applied to the fruit of oak trees, especially when they are used as food source for animals.

In Texas, oaks are important trees for wildlife as they provide acorns for food, shelter in their huge branches, and both food and shelter as they slowly decay.  For humans, oaks protect against soil erosion, buffer homes from strong winds, and provide true beauty in the landscape.  All of these benefits are derived from the simple yet astonishing acorns!