Taxonomy: This is a cladogram depicting a time-calibrated molecular phylogeny of conifers, showing the relationships between existing taxa and the estimated times since they shared a common ancestor (Figure 1 from Leslie et al. 2018).
Example of a LIDAR point cloud for a very tall Pinus ponderosa [M. Taylor, 2022].
Example of how photogrammetry can be used to precisely image and calculate the volume of an irregular trunk (the Grizzly Giant, a famous Sequoiadendron) [R. Van Pelt, 2022].
Description of Database Fields
Because this database is very much a work in progress, many fields are empty for many taxa. Fields may be omitted for some taxa, particularly above the species level.
The scientific name of the organism. Taxonomic names consist of two parts. The first part is botanical Latin and essentially consists of a one-word description of the taxon. For species, it's a two-word description because species are conventionally referred to by their "binomial", meaning one word for the genus that a species belongs to and one for the name of the species (its "specific epithet"). Sometimes the scientific name is descriptive; Abies grandis, for example, literally translates as "grand fir". Other times, the scientific name may describe the location where the plant was collected (Cryptomeria japonica) or commemorate a person, often the collector (Pinus maximartinezii); the "Remark" section often provides the derivation of the scientific name. The second part of a taxonomic name is the name of the author(s) who first described that taxon. This is a critical part of the name because the description prepared by that author is literally the definitive description of the taxon. (I say "literally" because some of the old descriptions, especially from the 19th century or before, are notoriously vague.) The naming of taxa is governed by a strict set of rules, the International Code of Nomenclature for Algae, Fungi and Plants. The study of plant classification and its associated nomenclature is called plant systematics or taxonomy; a good library will have some texts on the subject (I won't mention any because the technology moves so fast, a new textbook comes out every couple of years); see also the Wikipedia article on taxonomy. The fundamental goal of plant systematics is to classify all plants within a phylogenetic hierarchy, such that plants with a shared evolutionary history are placed near each other in the hierarchy.
Just as a reminder, here's the hierarchy of taxa, with examples in parentheses:
Phylum (Pinophyta)
Class (Conopsida)
Order (Pinales)
Family (Pinaceae)
Genus (Pinus)
Species (balfouriana)
Variety (austrina).
(Note that names above the rank of genus are not italicized.)
What is a species?
For that matter, what is a genus, what is a family, what is an order? Every plant taxonomist has their own, personal views on these questions, and I expect that every one will also find scientific names on this website with which they disagree. There is disagreement even at the highest levels - how many phyla there are in the Gymnosperms - and the controversy proliferates down the chain from there.
Some of the disagreement occurs because a name was once useful but has become outmoded in the face of new knowledge. For example, there used to be a widely known family of conifers called the Taxodiaceae, that included many famous species such as the redwood, Sequoia sempervirens. Some years ago it was conclusively shown that the Taxodiaceae are polyphyletic, meaning that they are not derived from a single common ancestor, and some of them are more closely related to species in the Cupressaceae than they are to their fellow members of the Taxodiaceae. All of the species formerly assigned to the Taxodiaceae are generally accepted to have closest relatives in the Cupressaceae, so the two families have been merged (there has also been a lot of reorganizing within the Cupressaceae). Note that although the Taxodiaceae are not a discrete phylogenetic entity, they are still unique and readily distinguishable from the rest of the Cupressaceae in some respects; for instance, they all have fairly low drought tolerance, whereas most of the rest of Cupressaceae has moderate to high drought tolerance. This points up the fact that there are reasons why a plant classification does not necessarily have to be phylogenetic to be useful; but this is not a widely-held idea, and modern plant systematics almost always seeks to understand the phylogeny of a taxon.
Disagreement between taxonomists occurs because of differing perceptions about what constitutes a species, as opposed to a variety or a genus, and this usually arises because of differing interpretations of evidence indicating similarities or differences between populations of plants. Before Darwin, people thought that "species" were literally sacred -- that God had created each species, separate and unique, but had not created varieties or genera or any other taxonomic group; these were simply Man's interpretation of God's work. So, when Darwin said that God didn't create species (he simply accepted that long ago, God created Life [footnote]), he was stating a scientific heresy, and it took about twenty years for most scientists to come around to his way of thinking. After this controversy had simmered down and he penned the final edition of "Origin of Species" (Darwin 1872), he could look back and say
It is quite possible that forms now generally acknowledged to be merely varieties may hereafter be thought worthy of specific names; and in this case scientific and common language will come into accordance. In short, we shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations made for convenience. This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term "species."
I agree with Darwin, and so I suggest you simply accept that this Database may not divide species up in quite the same way that other authors do, but that it does try fairly to set forth the great diversity of Gymnosperm life, and that it tries to incorporate the latest scientific knowledge with regard to questions about the origins and phylogeny of the taxa treated here.
"Common" names are vernacular names for a taxon, including non-English names where relevant (after all, the majority of conifers are native to lands where English is not the primary language). The definition of "common" is a bit artificial. Most of these plants have names used by native peoples within their range, but in many cases those names have been lost, as have the native peoples themselves. "Common" in the 21st century usually means "English," and many plants are known by nearly everyone outside of their native range by an English name, often one used in horticulture. In the database, I try to present the name of each plant using the dominant languages in use within its native range, as well as English and, where available, aboriginal names or names in other widely-used languages. See Pinus for an example.
A plant may have had a wide variety of scientific names over the years. These past names are called synonyms, and synonyms (abbreviated Syn.) are listed in this field. This field also describes considerations affecting the classification of a species. For example, the Database uses very recent genetic analyses to identify taxa of ponderosa pine (Pinus ponderosa) that are not, to my knowledge, treated outside of the strictly scientific literature. This is an example of the sort of taxonomic assessment I can present in the Database, that you will simply not see in any source prepared for the general public. The "taxonomic notes" field also notes known instances of natural hybridization that may locally blur the distinctions between related species, and hybrid taxa (such as the Albert spruce) are only described here, rather than having separate pages.
These days (2022) molecular analysis is largely the arbiter of taxonomic decisions. This is a complex subject, but briefly, it usually consists of sequencing portions of the DNA (or sometimes all of it) in a group of organisms, and using their similarities and differences to infer phylogenetic relationships. DNA useful for these purposes can be derived from chloroplasts, which only receive DNA from the male (pollen) parent; from mitochondria, which only receive DNA from the female (seed) parent; or from nuclei and ribosomes, which receive DNA from both parents. Sometimes these sources tell substantially different stories, and very different interpretations are possible depending upon which part of the genome is being studied. Thus caution is needed in interpreting molecular results before they have been tested by different, independent studies. Molecular analysis may also be applied to other chemical constituents of a plant; in conifers, it most often examines the volatile organic compounds that give conifers their distinctive odors. These essential oil studies can yield insights to phylogenetic relationships as well as to ecological and physiological aspects of the plant's biology.
Plant taxonomy is a complex subject and it's not practical for me to explain the principles and processes. However, the following Wikipedia articles give a good foundational knowledge of much of what I discuss:
The description tells you what the plant looks like, i.e. its readily distinguishable morphological features. In most cases, this includes the plant's stature, growth form, and characteristics of its foliage and reproductive organs. When I have information on phenology, such as when the cones mature, that is also presented here. The description may also mention subspecies, varieties, or similar species, and discuss how to identify them.
At a minimum, the distribution section lists the countries where a taxon is found. For many countries, it also lists local administrative divisions (states, provinces, etc.). It may also describe climate, soils, major vegetation communities, disturbance regimes, or other ecological matters influencing the distribution of the taxon. Since the majority of conifer taxa are to some degree threatened by human activity, and many are in danger of extinction, there is also usually a discussion of the species' conservation status. If the species has ecological importance, that is also discussed here.
For many species, there is a distribution map. There are three types of distribution maps in the Database.
The first and most traditional type is one that has been assembled by a dendrologist, often with the help of a cartographer, on the basis of both personal experience and professional knowledge of many different data sources. It is an inclusive map, by which I mean that it includes the entire range of the species, but also includes many locations and habitats where the species does not occur.
The second type is one that consists of locations associated with collections or observations, usually as recorded on herbarium sheets or using a "citizen science" app such as iNaturalist. It is an exclusive map: each data point represents a known occurrence of the species, but the species also occurs in many places not shown on the map. Also, a practical limitation of the map is that many herbarium sheets give location with very low precision. An older collection might simply say "northern California" for example. However, point maps are very useful because they show where the species really can be found, and I prefer them when I'm searching for a particular species, especially if it's a rare one. For most species, this is the best available map.
The third and best type of map uses point data in conjunction with a knowledge of species climate and habitat requirements along with habitat type maps and climate data. It combines these data to produce a predictive geographic model of where the species is likely to be found. These maps are laborious to produce but have been shown to be highly accurate, sometimes accurately predicting the species' location in places where it has not previously been collected. An example is the map for Pinus monophylla; see also the online Burchfield map referenced for Pinus longaeva. These maps are increasingly important, too, in the era of rapid climate change; by the late 21st century, most native trees will be occupying sites where the prevailing climate is not suitable for their successful reproduction, and predictive range maps will be essential for humans to plant trees in areas with suitable climate. For some species, such planting programs will be needed in order to avoid extinction.
I try to present data for both living and historical trees having superlative diameter, wood volume, height, age, or other remarkable attributes (e.g. culturally important specimens). Most data in this field come from organizations devoted to recording big trees (see Big, Tall and Old Trees). I do not present information on where to find these trees. Superlative trees tend to attract attention, and it is usually fatal, either suddenly (as when a tree is cut or burned by someone through accident, malice or mental illness; see Taxodium distichum for an example) or slowly (as its popularity leads to a decline in its root system and increased vulnerability/exposure to disease and injury; see Picea sitchensis for an example). If you care about these trees, it is usually best to leave them alone, except when that means leaving them unprotected from exploitation. See the "Ethnobotany" section of Sequoia sempervirens for a "happy ending" story of such protection, but also note that researchers preferred that the locations of both the largest and tallest specimens of that species remain a closely-guarded secret. That did not happen, though; the secret got out, and now (writing in 2022) both the largest and tallest specimens display considerable damage due to visitor-related impacts.
Technology has, during the 21st century, revolutionized the science of big trees in several ways. The tallest trees are now often discovered through processing of LIDAR data, a technology described by ESRI (2021); see also the image at right. LIDAR allows remote, precise height measurements to be done over very large areas, and the technology has been applied now to precisely assess all of the tallest tree species, including conifers such as Abies, Picea, Pinus, Sequoia, and Sequoiadendron. For many of these species, we now know not only the tallest tree, but the tallest 100 trees. Similarly, the "biggest" tree used to be defined by diameter, but LIDAR and related technologies, such as precise photogrammetry, now allow us to calculate the total wood volume in a tree, and this is now the preferred way to estimate tree size (image at right). Terabyte-sized datasets, however, largely restrict these technologies to scientists. It is possible, however, to buy a laser for as little as $100 (US) that will enable quick and accurate determination of tree heights with a precision that formerly required climbing the tree with a tape measure. The tape measure itself, however, remains cheap and reliable and is still the usual method used for assessing tree sizes.
If an age is known precisely, relevant details are provided. Age is one of the most frequently misrepresented attributes of a tree; countless trees are attributed great ages on the basis of no evidence whatsoever. In practice, it is usually quite difficult to accurately age an old tree; see How Old Is That Tree? for details.
Ethnobotany is the study of how plants are used by humans. This may include historic use, by native or colonizing peoples, as well as modern uses such as for timber, wood products, food, horticulture, or research.
Artificial hybrids are rarely included in the database. Neither are cultivars, and for that matter, horticulture is generally given short shrift. My interest in the gymnosperms is as an ecologist, so I prefer to deal with them as wildlife rather than cultivated plants. If you want to buy plants or seeds, or want to know how to grow these plants in your garden, then I suggest you consult gardening books or join a horticultural group such as the American Conifer Society. I also avoid any discussion of alternative medicine, a hot topic with regards to taxa such as Ephedra or Ginkgo. If you want to use gymnosperms as drugs, consult your doctor.
Dendrochronology is the study of tree rings, and is one field of scientific research that is entirely focused on trees, and mostly focused on conifers. Dendrochronology is not possible for cycads, which do not form annual rings, and I don't know of its being used for gnetophytes or ginkgo. Information on the dendrochronological uses of a species is either from my personal recollection, or cited from the literature.
The Observations section discusses especially good places to find the taxon. Usually I try to describe where to find it in habitat, except for certain rare species that may be endangered by irresponsible collection. For these, I try to give examples of exceptionally good specimens in public collections (botanical gardens and arboreta, usually).
The Remarks may include anything of interest that doesn't fit into one of the preceding fields, such as derivation of the scientific name, or the plant's role in history.
Bibliographic citations. Format is fairly standard. Links are provided to sources generally available on the Internet. For dead links, you can often find an archive copy of the page by using the Wayback Machine.
Printed references or links that are not included in the Citations, but will provide useful further information. As the years go by and the level of knowledge about gymnoperms continues its exponential growth, it is ever more difficult for this website to contain even the most important information about every gymnosperm taxon. Nonetheless, I still try to show you where to find that information.
N, S, E, W, C = North, South, East, West, Central. Sometimes I use the abbreviations for states in the U.S. or provinces in Canada, but abbreviations are not used in the "Distribution and Ecology" description in order to simplify the task of searching for all taxa within a particular geographic area. For that, just search for the names of countries (or states/provinces for Australia, Canada, China, India, Mexico, Russia, and the United States).
The database started as a group of word processing documents, subsequently converted to HTML 1.0, and updated since to the point where most pages are now HTML 4.0 using features like CSS, PHP, and javascript. I have tried to minimize using browser-specific features in an effort to make this material available to anyone. However, there are a couple of javascript routines that are called literally thousands of times, and these I can't work without. As best I can tell, everything works well on all currently-popular browsers running under MacOS or Windows. Others, I can't test. Since the database has been a work-in-progress since 1997, the size and quality of images varies enormously. Currently (2021) I use thumbnails with a maximum dimension of 140 pixels, and linked images with sizes of up to 1920 x 1080 pixels.
Darwin, Charles. 1873. The Origin of Species by Means of Natural Selection. London: John Murray. Available: Internet Archive, accessed 2022.04.19.
Leslie, A. B., J. Beaulieu, G. Holman, C. S. Campbell, W. Mei, L. R. Raubeson, and S. Mathews. 2018. An overview of extant conifer evolution from the perspective of the fossil record. American Journal of Botany 105(9):1531–1544.
Last Modified 2024-10-08
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