Why do Botanists Always Tell You the Plant Family? repost

Repost from 2013: Why Botanists Always Tell You the Plant Family

choke cherries, rose family, Rosaceae

People writing about plants are forever sticking the plant family into the discussion.

Plant Names and Families

Indian temple tree (Plumeria, dogbane family, Apocynaceae)

Some of my earliest blogs (spring, 2013) were about botanical classification because I wanted to explain why I used it.

I recently settled down to read a technical book on ecology and found the references (Somebody 2002, Somebodyelse and Coauthor 2011) distracting. Annoying, actually. There was a time when I read over those without a thought.

I elected from the beginning to include references in this blog, but only at the end. But I do stick in technical plant name information (Fancylatin name, twig family, Fancylatinaceae), every time I mention a plant. I am not about to give that up, intrusive as it is. So perhaps I should explain again.

Common Names -- Different Names in Different Places

I've been drawing attention to problems in looking up plants online by their common names. Here is one final issue with common names: they are often regional. That means you can find the same name on a different plant if you are in a different part of the United States. Or not find useful websites because on those websites they use a different common name.

goatsbeard, Tragopogon

For example, looking at plant books from different regions, I find two goatsbeards, Aruncus dioicus (see photos I don't have one of my own) and Tragopogon spp. (above and photos). Aruncus grows across the eastern US., Canada and along the West Coast (USDA maps, description at Missouri Botanic Garden). Tragopogon grows there too, but eastern U.S. books it is called salsify or oyster plant. Aruncus is not found in the central U.S., and in some plant identification books from here, it is Tragopogon that is called goatsbeard. I believe the name goatsbeard for Tragopogon came with it from Europe (see Culpeper, Grieve). Aruncus is an American species, more recently named goatsbeard, for the way it looks. Currently, the USDA plants website has Tragopogon as goatsbeard and Aruncus as bride's feathers while the Flora of North America calls Aruncus goatsbeard and Tragopogon salsify. No knowing what you'll get if you ask for goatsbeard. 

Common Names--What a Mess!

Saskatoon berries, or you might know them as...

Here are the fruits on my saskatoon--you might know them service berries or June berries. In the East you might call this a shadbush. Robins don't argue over the names, they just gobble the fruits down.

To entertain with the stories I love, I have to identify the plant. That is what names are for--communication. Why is it so difficult to have widely recognized plant names?

Botany Rules: How Can Some Plants Have Two Scientific Names?!

Buchloë dactyloides or Bouteloua dactyloides ???

Botanists routinely assert that each plant has only one scientific name. When you look up a plant and find two authoritative sources giving different scientific names, botanists seem like liars.

I recently encountered that with buffalo grass, listed as both Buchloë dactyloides and Bouteloua dactyloides. (posts on buffalo grass: and bison, drought-tolerance)

Botany Rules: Why Change Scientific Names?! Part 2

stiff sunflower Helianthus rigidus
when the photo
was taken, now Helianthus
pauciflorus

     Plant names of American plants are changing more right now than they have for centuries because of the joint impact of the Flora of North America Project and DNA sequencing. I talked about the Flora of North America project last post.  LINK   

  There would certainly have been changes in American plant names as a result of the writing of the Flora of North America, but the concurrent emergence of DNA sequencing has produced surprising new data to integrate. 

      Compared to animals, plants have a simple structure. Botanists recognize only three tissues: root, stem and leaf. Flowers and fruit are specialized leaves. From descriptions of the arrangement and details of these three tissues botanists created plant classification. They used all the tools they had: complex measurements, chemical analysis, geographic patterns, and ability to hybridize, for example. 

  

     After 400 years of applying these techniques, plant biologists thought they were pretty close to having found the true relationships among plants. They were wrong. DNA data has revealed many surprises. In particular, it has shown convergence, where two plants look very similar but turn out not to be closely related at all. For example, flowering plants living in ponds or streams have similar characters for living in or under water, but their ancestors are found all over the plant kingdom. 

Botany Rules: Why Change Plant Scientific Names?! Part 1

Trientalis europea, formerly Trientalis latifolia. Why?

   Two very important things happened to plant names in the botanical world starting in the 1980s:  the flora of North America project and DNA sequencing. I'll talk about the Flora of North America today and DNA sequencing next time.

     For the post on California coastal forests ( LINK) I looked up the plants I saw this May in plant books published in the 1970s. I found the plants but when I checked, almost all the names had been changed. Specifically star flower, in the old books as Trientalis latifolia is now Trientalis europaea, what was called Rubus vitifolius, the Pacific dewberry is now Rubus ursinus and Montia perfoliata, miner’s lettuce is now Claytonia perfoliata, 

   Books and botanists tell people that each plant or animal has only one scientific name so it is surprising and a bit annoying to discover the name you learned is incorrect.   

    Why?

Plant Story: Common Houseleek, Sempervivum tectorum, Folklore

Sempervivum tectorum, hens-and-chickens, aka Jupiter's  beard
stonecrop family, Crassulaceae

   One widely-planted succulent (see previous post) is the plant I grew up calling hens-and-chickens Sempervivum tectorum (Crassulaceae, stonecrop family). These days the preferred common name seems to be houseleek. There are 34 genera and 1,400 species in the Crassulaceae, with 30 species of Sempervivum and hundreds of Sempervivum hybrids and cultivated varieties. Sempervivum tectorum thus gets called the common houseleek, since you might want to call all the other sempervivums houseleeks too. 

   Native to Europe, the common houseleek has been grown in and around human settlements for millennia. Like many plants that are familiar to a lot of people, it has many common names. Frequently used in the U.S. are hens-and-chickens and common houseleek. More obscure common names are Aaron's rod, bullocks eye, Jupiter's beard, Thor's beard, syngreen, and a half dozen more (see Wikipedia entry).

Sempervivum tectorum rosette -
note thickness of leaf I broke

   The scientific name, Sempervivum, means "live forever" (semper = always, vivum = living), as does the common name syngreen and its variants. This doubtless refers to the fact that uprooted plants can survive for weeks, living on their stored water. Pluck up a pansy (Viola tricolor) or a dandelion (Taraxacum officinale), with or without roots, and in hours they are wilted and in a day or two, dead. Do the same thing to a rosette of hens-and-chickens, and more than a week later you can stick it back in  moist soil and it will recover. Try it!
This is the benefit of storing water the way a succulent does.

   The hens-and-chickens common name follows from the growth form, where little clones are grow around the initial plant. (See picture below, but I don't have a really classic photo of hen with chickens.)

hens-and-chickens in
rock garden in Colorado

    The tectorum in Sempervivum tectorum and the English names Jupiter's beard, Thor's beard and houseleek all refer to the plant's long association with lightning.

     This is a story that seems very odd to us in the modern world.

Botany Rules 3: Why do Botanists Always Tell You the Plant Family?

choke cherries, Rose family, Rosaceae

        People writing about plants are forever sticking the plant family into the discussion.

Ipomoea,  Convolvulaceae,
morning glory family

      The photo to the right is a morning glory, Ipomoea (morning glory family, Convolvulaceae)

yarrow, Achillea 
millefolium,
Asteraceae,
sunflower family

   To the left, yarrow, Achillea millefolium, (sunflower family, Asteraceae)

    That intended to be helpful. There are at least 300,000 species of land plants. Nobody knows all 300,000. They are organized into classes made of orders, made of families, made of genera and species. Most of the land plants, about 280,000 species, are flowering plants, angiosperms, and are in the same class. There are approximately 60 orders, 400 families and 12,000 genera of angiosperms. Orders are so big that they contain very diverse plants. For example the order Asparagales includes orchids, onions and century plants. Writers include the plant family in hopes that you’ll know one plant in the family mentioned and it’ll give you a decent guess what the plant described is like.

  
      Here, for example, are capsule descriptions of a few major plant families, not intended to describe their characteristics as much as to prod your memory of them. Plants differ and botanists group them based on those characteristics, so plants in the same family share important characteristics while those in different families seem, and are, different.

rose, Rosa sp., rose family, Rosaceae

   For example, members of the Rose Family have a ring of five petals around a center and produce a usually fleshy fruit with a few hard seeds inside. Lots of them are shrubs or small trees. Members of the rose family, in addition to roses, are apples, plums, apricots and pears.

Botany Rules 2. Scientific Names, Genus and Species

prickly pear cactus

 As every basic biology class explains, scientific names were created to organize communication about plants and animals. In the 1500s and 1600s, Europeans spread out over the globe and brought back all kinds of unknown organisms. By the early 18th century, they had chaos--lots of organisms and no system of organization. 

morning glory, Padre Island, Texas

morning glory  Happy Grove, Jamaic

    Here’s a purple-flowered morning glory from the beach in from Jamaica and in Texas. Same or different? 

yarrow, Boulder Colorado

Yarrow from Narvik, Norway and Boulder, Colorado. Same or different?

yarrow, Narvik Norway

   

   
     Linnaeus set up a hierarchical system: groups are made of subgroups made of more subgroups. It was logical and mostly it worked. His hierarchy was Kingdom, Phylum for animals/ Division for plants, Class, Order, Family, Genus and Species.