Showing Off the Woodies

Shrubs and trees often have beautiful flowers. Their woody stems give them a certain rigid architectural quality that can serve as a framework for herbaceous, stemmed flowers in an vase.

Hamamelis virginiana
Hamamelis virginiana

Shrubs begin flowering before leaf out in the spring. Your spring may begin with spicebush (Lindera benzoin), the so-called “forsythia of the woods,” and end with witch-hazel (Hamamelis virginiana), a shrub with flowers that persist after the leaves falls. Between April and November there is a continuous string of flowering woody plants.

The tiny yellow flowers of spicebush have a striking form; they float in the understory of the forest in flat sprays with a single shrub supporting blossoms at many levels. This horizontal arrangement is in marked contrast to the actual forsythia, a so-called “cane shrub.” Its form consists of wands thrown up vertically until they droop under their own weight.

Spicebush is a laurel and that family is noted for its brilliant floral displays. The mountain laurel (Kalmia latifolia) is not actually a laurel; it is a member of the heath family (Ericaceae). Ericads like azaleas, rhododendrons, and the mountain laurel are all well know as cultivars, but there are dozens of wild species that may be available from nurseries if you live in an area where landscaping with native plants has caught on.

Rhodora
Rhodora

In the Northeast wild varieties include the flame azalea (Rhododendron calendulaceum), rhodora (Rhododendron canadense), the pinxter flower (Rhododendron nudiflorum), and the great laurel (Rhododendron maximum). The first three are all small deciduous shrubs, but the last is an evergreen that can reach a height of 35 feet.

During the so-called Hypsithermal, or Holocene climate optimum, between 9,000 and 5,000 years before present, many plant and animal species spread northward as part of the recovery from the last Ice Age. The climate has been generally cooler since and many species retreated southward, but left behind “relict” populations in isolated northern areas where the climate was suitable for survival. One example of this is the scattered groves of great laurel that can be found through Connecticut, Massachusetts and southern New Hampshire. Rhododendron State Park in New Hampshire preserves the northernmost known site. The 16-acre grove blooms in mid-July.

redbud
Cercis canadensis

In addition to shrubs, some small understory trees have striking blossoms. The redbud (Cercis canadensis) is found in the wild north to the Southern Tier of New York, but it (or its Chinese cousin) have been planted extensively as ornamentals and it tends to spread rapidly where introduced. Some of the flowers erupt directly from the wood on fairly old branches, which makes the tree quite a sight when it blooms in May, bright fuchsia flowers against nearly black bark. The flowers are most profuse on the newer growth, where they are arrayed in drooping masses.

When the redbud is fading the lilacs (Syringa vulgaris) begin to take off. Although native to Europe and Asia, lilacs have been popular “foundation shrubs” in the United States since the late 18th century. One can often find them seemingly growing in the wild where a farmstead has burnt down or been abandoned years before and only the plantings and a few stone walls are left. The aroma of lilacs is quite strong and some may find it overbearing in a confined space. The most common colors are shades of purple, but pinks and whites are common as well.

Viburnum plicatum
Viburnum plicatum

As the summer progresses the viburnums become prominent. This is a large family and both introduced ornamentals and native species are widely planted. The nannyberry (Viburnum lentago) is a showy native, while Viburnum plicatum is a commonly seen and interesting ornamental from eastern Asia. V. plicatum has corymbs of small white flowers surrounded by larger, showier sterile flowers.

Even larger trees can have showy blossoms worth collecting and putting on display in a vase. Horsechestnuts and buckeyes (Aesculus spp.) have large spikes of white or pink flowers. Tulip or yellow poplars (Liriodendron tulipifera) have subtler yellow and orange cups that do, in fact, resemble tulips. Fruit trees, especially those in the rose family, such as apples, cherries, and peaches, have gorgeous white to pink flowers. The cherry displays of Washington, D.C. and urban Japan are revered and celebrated.

The traditional way to increase the surface area for the absorption of water once a woody plant is cut is to crush the base of the stems above the cut. A florist has recently informed me that this is not actually necessary, but it does work.

Advertisements

Fickle Plant Classification

<i>Alstroemeria saturne</i>
Alstroemeria saturne

One of the flowers that will live longest after it is cut is the Peruvian lily, or “lily of the Incas”. The blooms will last two weeks in the vase, but the leaves will not, so you are advised to strip off the leaves before putting them in water.

The popular names of this plant are, in this case, more or less accurate. Which is to say, they do originate in the Andes, but they have two centers of diversity: one is a winter-blooming group in central Chile, and the other is a summer-blooming group in eastern Brazil. From these points of origin approximately 90 wild species have developed, ranging from Venezuela in the north down to Tierra del Fuego.

They are also, in fact, lilies. The genus Alstroemeria, after some taxonomic revision over the last decade, has been, placed in the family Alstroemeriaceae. (They were once placed in the Amaryllidaceae with the daffodils.) The family also includes the genera Bomarea, Schickendantzia and Leontochir, and is part of the order Liliales in some taxonomies and included in the order Asparagales (in the class Liliopsida) in others.

Systematics is a part of natural science where controversy will never truly go away. Although all biologists agree that all living species can be traced back to a common ancestor, there is no common, all-inclusive consensus as to how everything is related.

When Linnaeus established the binomial nomenclature in the 18th century and began grouping living organisms together, he wasn’t even thinking of them as having a common ancestor. Rather he was just trying to bring some organization to the classification of organisms. Most Enlightenment naturalists felt that they were in the business of perceiving the logic of the divine plan, not describing a branching evolutionary scheme. It was believed that the similarities among species were a product of variations on themes that existed in the proverbial mind of God. Darwin’s theory of natural selection introduced a mechanism that provided a means for defending the idea that species were similar because of common descent rather than due to repeated tweaking of a heavenly mold.

Through the last half of the 19th century (On the Origin of Species appeared in 1959) taxonomies (i.e. theories of systematics) were based on identification of shared morphological traits. The more traits shared, the more closely related the taxa. The arguments in that era were over which traits were the right ones to use and what weight to give each trait. The early 20th century development of the field of genetics largely verified and clarified the taxonomies of the previous century, but the introduction of molecular genetics in the 1960s and the eventual analysis of shared genes by the 1980s, changed the study of taxonomy.

Willi Hennig
Willi Hennig

While relatedness was implicit in post-Darwin classifications, the systems were called ‘phenetic’ because they were based on traits that could be observed in organisms, but the ordering of the traits was entirely based on the erudition of the classifier, not a mathematical model. The presumption of evolutionary relatedness was brought to the fore with to the development of cladistics and phylogenetics. Multi-variate statistics were brought to bear on the question of which traits to use and how much weight to give each one. As more powerful computers became more accessible to more people, the analysis of data in this way became more commonplace and the phylogenetic approach became pre-eminent.

Arthur Cronquist
Arthur Cronquist

Arthur Cronquist, a botanist at the New York Botanical Garden, developed the most widely used phenetic taxonomy of plants beginning in the 1960s, before the advent of cladistics. He published the first edition of his The Evolution and Classification of Flowering Plants in 1968 (second edition 1988), 11 years before Willi Hennig issued Phylogenetic Systematics, the inaugural work of the cladistics movement. Cronquist’s system is still used by some botanists, but many have adopted the taxonomy of the Angiosperm Phylogeny Group (APG), which was published in 1998 and revised in 2003 as APG II. The APG system is based on the cladistic analysis of the DNA sequences of three genes, two chloroplast genes and one gene coding for ribosomes. It has drastically revised some parts of Cronquist’s system, particularly his Liliopsida class, which included all the monocotyledon-bearing plants.

The United States Department of Agriculture still uses the Cronquist system and still has Alstroemeria in the Liliaceae, while the Daviswiki, the “creative commons” for the California city that is home to the premier horticultural arm of the state university system, and the Atlas of Florida Vascular Plants keep the genus in the Amaryllidaceae. The International Society of Horticultural Scientists (ISHS), of course, uses Alstroemeriaceae name and is busy working out ‘genetic linkage maps’ among the wild species. The APG II (unchanged from the APG, in this case) recognizes the family and puts it in the order Liliales in the clade monocots.