Notes on taxonomic issues for curators.

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Notes on taxonomic issues for curators.

• A very basic introduction.
• Alan Whittemore, U. S. National Arboretum

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Common problems requiring taxonomic information

• You have a plant with no name, or you are not
  confident of the name.
• Your plant was reliably named, but the name is no
  longer in use.
• You want to target relatives of your crop for
  preservation, and you need complete lists of
  related taxa.
• You are preparing herbarium specimens or
  photographs, and you want to make sure that
  you're capturing the characters that are
  important taxonomically.

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Resources for taxonomic information

• Some general notes on whats available

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• Mabberleys Plant Book is a good starting point
  for general information on a group of plants.

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Mabberley gives the number of species, native
range, family placement for genera, economic
uses, common names, and references to monographs.
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Heres his treatment of Juglans.
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Mabberley is good for finding obscure common
names, too.
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Monographs are thorough taxonomic treatments of
particular plant groups. They commonly include

• Keys, descriptions, synonymy, discussion,
  illustrations.
• Discussions of past erroneous usage and current
  problems.
• Discussions of variability within and among taxa.
• Specimen citations.
• Studies of species relationships and evolutionary
  history

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There are hundreds of thousands of plant species
and very few taxonomists, so most groups haven't
been monographed, at least not in decades or
centuries.

• If a good monograph is available, it may contain
  a great deal of information on the biology of the
  group, as well as its taxonomy.

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Manuals are treatments of limited groups of
plants - often, those of a particular region.

• Some cover weeds or cultivated plants, but most
  are floras - treatments of the wild plants of a
  region.

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Manuals vary in how much data they contain.

• Some may present detailed data and discussions.
  Others may give very brief treatments. They
  often contain references to other literature,
  including recent monographs.

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It's worth getting to know the floras from areas
where your plants are native. They often are
the best sources for information on the species,
their synonymy, their wild relatives, and
characters that distinguish the taxa.
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Here are a few pages from the Flora of North
America, which gives keys, descriptions,
illustrations, range maps, ecological data, and
discussions of taxonomic changes, excluded
species, and other issues.
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Even if you can't read a flora, you can get
useful information from it - starting with a list
of species found in the region.

• In the next slide, you don't have to read Chinese
  to see that the author

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considers Solanum capsicastrum a synonym of S.
pseudocapsicum var. diflorum.
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Checklists commonly give accepted names,
synonyms, and often literature references.

• They are useful if you just need a list of
  recognized species, or if you have an old name
  for a species and you want to find the correct
  name.

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The herbarium allows you to compare your plants
with authentic material.

• Arrange beforehand if you want to bring dry plant
  material into an herbarium. Dried plant material
  is an insect hazard, and normally it must be
  frozen for several days at -80C before it will
  be allowed into the room where the collection is
  housed.

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Working with outside taxonomists.

• Professional taxonomists may be more familiar
  with the taxonomic literature, more practiced in
  identifying dried plants, and may have access to
  herbaria with species that you haven't seen.

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A specialist who is doing taxonomic research on
your group can be a very useful resource. In
addition to checking identifications, s/he may be
doing fieldwork in areas of interest to you, may
be able to give you precise locations for
populations of species you would like to get, may
have specific data on species relationships, and
may be aware of unusual populations or possible
undescribed taxa that could be of value to you.
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Taxonomists working on the flora of an area where
your group is native can help with localities,
local contacts, and information on local
conditions. Collaborating on fieldwork could be
beneficial to both sides.
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Developing long-term relationships with
taxonomists in your field can be a valuable
investment. John and I can help you find out who
might be doing work relevant to your collection.
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A specialist in your group may be able to name
your plants very easily. For others, it may
require a significant investment of time to find
all the literature and get to know the group.
Some groups are much harder than others, of
course.
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If you want to send plants for identificationCon
tact the taxonomist in advance, make good-quality
herbarium specimens, and keep in mind it may take
some time. Taxonomists tend to travel a lot, and
few of us get much administrative support for
time spent identifying other people's specimens.
We have to fit it in around other activities.
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How much plant material can you send without
overloading your taxonomist?

• There's no hard-and-fast rule. Ask the
  taxonomist how much s/he can handle. Keep in
  mind The more you send, the longer it's likely
  to take to get an answer back. A few specimens
  will often be looked at just to get them out of
  the way. Large shipments are set aside until the
  taxonomist has time to tackle a large project.
  (We all know how that ends.)

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Making herbarium specimens

• Plants are dried under pressure in a press, with
  corrugated cardboard inserted to allow air
  circulation and drying.

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The corrugations run side to side, not end to
end, to allow maximum air circulation.
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• Get enough pressure on it. Standing on it is
  about right, if youre heavy. Keep tightening it
  until dry - the press will loosen as the
  specimens shrink and flatten.

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Dry plants by forcing dry air through the
corrugates. This is usually done by placing the
press sideways above a low heat source. The
purpose of the heat is to make the air rise and
circulate and to drop the relative humidity - not
to heat up the plant material!
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Low wattage incandescent lights make appropriate
heaters for drying plants.
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Be as sparing as possible with the heat, but make
sure that there's air circulation - otherwise you
will just grow fungi. Heat makes wet plant
material go moldy, and it makes dry plant
material fade and become brittle. Take plants
off as soon as they are dry. Evaporation keeps
them cool while they're drying, but as soon as
they're dry they heat up.
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Tips for preparing good specimens

• -- Pay attention to the size of the specimen!
  Specimens that are even a little bit larger than
  the sheet can be very difficult to mount once
  they're dry and brittle.

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-- Preserve the important parts of the plant! If
you don't know what's important, look up the
genus in a few appropriate manuals look at the
keys, and see what organs of the plant they ask
for.
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Here's part of the Allium key from the Flora of
North America. There are lots of flower and bulb
characters here - make sure you get these organs.
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-- Make sure that the characters show! Press
organs face- or side-on, not crumpled, and turn
over a leaf or two so that both leaf surfaces
will be visible after the specimen is glued
down.-- Put the data on the label - don't
expect people to look it up in your database when
they're keying the plant! URLs change, and I can
assure you that when youre examining 150
specimens of a species, you soon give up trying
to find remote data on a sheet-by-sheet basis.
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Plants vary from quite easy to press and dry
(many herbaceous plants) to very difficult.
Succulents require specialized techniques
plants with very large organs (palms, etc.)
require a real knowledge of the essential parts
of the plant, since so little of it can be
pressed.
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• For special problems, check herbarium literature,
  like The Herbarium Handbook. It will give you a
  lot of information about how to solve different
  problems.

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The herbarium label should state

• Where the plant was collected. If the seed came
  from a known location, tell us where it came
  from, too.
• Collector's name and collection number.
• Date of collection.
• Notes on characters that don't preserve - flower
  color, height and growth form of a tree, etc.
• Other information of interest - PI number,
  economic use, common name, etc.

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• Heres an economic collection from North
  Carolina, documenting use as well as locality
  (see next two slides).

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• Collection notes taken by Frank N. Meyer in China
  in 1914.

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Notice that many specimens have later annotations
as well as the original label.When specialists
examine the specimen, they give their opinion in
writing. The specimen becomes documentation of
their work and their scientific conclusions.
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This wild potato relative has been annotated by
all three of the great potato taxonomists -
Donovan Correll, John Hawkes, and David Spooner.
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Specimens like this become more and more valuable
as time goes by. They allow you to see and check
the data and conclusions of experts who have
worked on the group, long after they are gone.
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Your relationship with herbaria

• They devote time, space, and money to preparing
  and maintaining the specimens. Their reward is
  to add well prepared specimens with good data to
  their collections.

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If a local herbarium is interested in preserving
your specimens, should you put them there or at
the National Arboretum?

• Both is best - collect duplicates, and deposit
  one in each place. Building ties with your local
  (usually university) herbarium is good. Warning
  right now herbarium funding almost all comes from
  wild plant work, so you may find them reluctant
  to devote space and resources to cultivated
  plants. This is unfortunate, but it's the way
  things are right now.

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Collecting in duplicate makes the collections
more secure. We work hard to preserve the
world's plant collections, but two important
herbaria were lost in the 20th Century the
California Academy of Sciences burned in the fire
following the San Francisco earthquake of 1906,
and the Berlin Herbarium, one of the largest in
the world, was accidentally bombed during World
War II.
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Most herbaria are now databasing their holdings,
but there is a lot of material to catch up on,
and I know of no large herbaria that are even
close to fully databased. The National Arboretum
herbarium database now has about 45,000 of our
650,000 specimens. We continue to database
important collections, and we hope to post the
database to our website when our webmaster
position is filled.
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Detailed locality data is often suppressed on web
postings, to prevent the destruction of rare
plant populations and to protect the privacy of
the current landowners. If you find a specimen
of interest, the herbarium can tell you if more
data is available.
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Taxonomists now have very good tools for
analyzing genealogical relationships among taxa.
Studies of many groups of plants are available.
Most of these analyses are found in recent
journals.
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• Heres one cladogram from a recent DNA study of
  Physalis. The old classifi- cation of the genus
  didnt hold up in this study.

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Data like this can be very helpful in identifying
close relatives of your crop. Likewise, NPGS can
be a big help to the taxonomist who is looking
for material of different species.