12 Feb
Part I: History of Plant Taxonomy
Taxonomy is perhaps the oldest branch
of botany. Many early human civilizations categorized plants based
on practical uses such as food, medicine, timber, tools,
weapons etc. We have records of Chinese, Indian, Egyptian and
Meso-American plant names and classifications that are thousands
of years old. These "folk" taxonomies often made very
accurate distinctions and were sometimes quite sophisticated.
2000 B.C. Atharva Veda (Parashara) was a treatise on the medicinal uses of plants and delimited a number of present-day species.
The science of Western taxonomy vs. practical or folk taxonomy arose out of the Mediterranean region (which is one reason why we have a legacy of Latin names).
Pre-Renaissance or "form" based taxonomy:
Theophrastus
(Greek, 370-287 B.C.)
Studied with Plato and Aristotle. His was the first recorded system
that organized plants by their intrinsic nature vs. practical
uses.
Theophrastus
1) classified plants into 4 "great groups" - trees,
shrubs, subshrubs
and herbs.
2) recognized that there were several kinds of sexual and asexual reproductive systems.
3) recognized that the calyx and corolla were modified leaves AND that the fruit developed from the ovary.
4) recognized that plants do not always breed true from seeds.
5) described over 500 plants and named them, including Asparagus and Narcissus (daffodils).
He was an early Western vegetarian and thought that it wasn't natural for humans to eat animals - he believed that the practice of meat eating must have evolved when early civilizations had their crops destroyed by war.
A small family of dicots from the New World tropics, was named for him (Theophrastaceae).
Pliny the Elder (Roman,
A.D. 23-79)
Published approx. 37 volumes on natural history including plant
taxonomy. When moveable type was invented in the 15th century,
these works were among the first books printed. Pliny died on
Mt. Vesuvius during an eruption.
Dioscorides
(Greek, A.D. 1st century)
Was a contemporary of Pliny and a physician in Nero's army. Was
one of the first to recognize superficial relationships between
groups of plants. Wrote de Materia Medica (ca. A.D. 77)
, which named and described the medicinal uses of over 600 plants.
This volume continued to be used throughout Europe for the next
1500 years!
Little work of new botanical significance was made during the Middle Ages, but Albertus Magnus (1193-1280) was the first to recognize the difference between monocot and dicot seeds (in de Vegetabilis).
Renaissance taxonomy ("Age of Herbals" ):
As the 16th century began, there were still only about 1000 described plant species. Books illustrated with woodcuts started to become more common during this period and the many new plant descriptions of the era were generally made in the form of medically oriented herbals.
It is important to note that this lecture is following the history of European botany. In China, where traditional plant-based medicine is still widely practiced today, extensive herbals were being compiled both before and during the European Renaissance period. The Cheng Lei Pen Tsao (Tang Shen) was written in 1108 and new editions continued to be revised and published for 500 years.
During the 17th century, world exploration brought huge numbers of plants back to Europe, many of which did not fit into the taxonomic schemes currently in use. The need for a formal, comprehensive system of classification was becoming apparent.
Andrea Caesalpino
(Italian, 1519-1603)
Described 1520 species of plants, arranged into categories of
herbaceous or woody. Caesalpino recognized that the characters
of the flower and fruit were more useful to taxonomy than those
of habit and form.
Gaspar Bauhin
(German, 1560-1624)
Came up with the idea of an international (i.e. European)
register of plant names. He was the first botanist to suggest
hierarchical classification concepts more detailed than the 4
great groups of Theophrastus, AND the first attempt using bionomial
nomenclature.
John Ray (English, 1628-1705)
A blacksmith, Ray traveled extensively and was a keen observer
of plant form. He catalogued 18,000 species and further divided
the system of Theophrastus to include 25 dicot and 4 monocot classes.
These groupings included the modern mustard, mint, legume and
grass families.
Sexual system of plant taxonomy:
Carolus Linnaeus
(Swedish, 1701-1778)
Student at University of Uppsala. His work was the culmination
of centuries of botanists striving to create a workable plant
classification system.
1) Assumed reproductive features were more important than vegetative and incorporated these ideas into his "sexual system", published as Systema Naturae in 1735. Many of the 24 categories in the sexual system had to do with number and degree of fusion of the stamens. This system was hierarchical and artificial. Plants grouped by external similarity, not biological relatedness. But later in his career, he recognized that species could arise through hybridization.
2) Formalized bionomial nomenclature. Before this, plant names were confusing and cumbersome. For example, before the Linnaean system, Drimys winteri was known as Periclymenium rectum folius laurifolius OR Laurifolia magellanica cortice acori.
3) 1 May 1753: publication of Species Plantarum . 1000 genera, 7300 species. Names published before this date have no nomenclatural priority.
4) Required herbarium specimens as permanent historical records and type species to document each named species.
Early "natural" systems:
As worldwide exploration continued (late 1700's), botanists realized that there was some "natural affinity" between plant groups above and beyond structural similarity, even thought they still had no concept of evolution.
Michel Adanson
(French, 1727-1806)
Explored flora of Africa. Rejected Linnaean system in favor of
his own.
Antoine-Laurent de Jussieu (French, 1748-1836)
Published the work of his uncle, Bernard, who was a contemporary
of Linnaeus and was dissastified with the sexual system. Jussieu
is credited as the starting point of conserved plant family names.
Jussieu recognized that plant relationships in nature were continuous - there were no breaking points. Distinct classification groups were the work of man, not nature. He felt that a taxonomic hierarchy was just a set of words, each one referring to part of the natural continuum, constructed for human purposes only.
Augustin Pyramus de Candolle (French 1778-1841)
With his son and grandson continued to work on Jussieu's system.
Described 59,000 species. Placed ferns with monocots and gymnosperms
with dicots. Non-vascular plants, including fungi, were a separate
group called Cellulares.
European botanists had enormous respect for scientific authority. If a group had been "recognized" for centuries , this was sometimes taken as evidence that it was a natural group and systematists were often reluctant to make modifications.
Asa Gray
(American, 1810-1888)
Only North American botanist considered by Europeans to be fully
their equal. He also proposed a pre-Darwininan natural classification.
Post-Darwninan "natural" and modern classification systems:
Charles Darwin
(English, 1809-1882)
Proposed descent with modification, although he didn't understand
the underlying mechanism.
Botanists since Darwin have tried to make
their classifications reflect evolution. We have already discussed
Engler & Prantl, and Charles Bessey in some
detail and mentioned other botanists who proposed evolutionary
scenarios (and thus classification schemes) for the plant kingdom
(John Hutchinson, Lyman Benson, G. Ledyard Stebbins, Arthur
Cronquist, Armen Takhtajan, Rolf Dahlgren and Robert Thorne all
made important contributions to pre-molecular plant classification).
Part II: PLANT COLLECTORS IN ALASKA
Sir William Jackson Hooker
19th century botanist at the Royal
Botanic Gardens, Kew (and earlier at Glasgow). He catalogued hundreds
of specimens sent by plant collectors from all over the world
(including North America). Made Kew into a great institution filled
with specimens from the Era of Plant Hunters. Was benefactor of
David Douglas.
Archibald Menzies
Early 1790's was appointed surgeon-naturalist
on HMS Discovery under Capt. George Vancouver. First scientist
to explore PNW. Has 6 species and 1genus named in his honor -
more than anyone else. When his dried specimens and plant descriptions
from the PNW reached England, they aroused intense interest in
increased botanical exploration of the region.
Karl Heinrich Mertens
Circled globe 1826-1829, but spent most time collecting in
Sitka (you will be keying a lot of taxa bearing the specific epithets
mertensiana or sitchensis!).
David Douglas (Scotland,
1799-1834)
Left school at 11 to take a gardening apprenticeship. Impressed
William Hooker at Glasgow who became his patron. Made two journeys
to North America. On his first trip to the PNW, he walked and
canoed over 6000 miles, alone. His second voyage took him to SE
Alaska, Siberia, California, and along the Columbia and Fraser
River drainages. He never returned to England. Douglas is responsible
for introducing over 240 new plant species to the UK, including
economically important taxa such as Pseudotsuga menziesii
(Douglas fir) and Picea sitchensis (Sitka spruce). He introduced
the Monterrey pine (Pinus radiata, from California) to
New Zealand, a species which now represents over 90% of the acreage
planted for timber in NZ.
Known for his excellent, detailed journals, bad eyesight and terrible temper.
Died at 35 on the slopes of Mauna Kea, Hawai'i. He fell into a hidden pit dug by islanders to trap feral cattle and was gored to death by a bull. Foul play was suggested, but never proven. The morning of his death he met Ned Gurney, an ex-convict cattle rancher who says he warned Douglas of the pit. Records uncovered in England in 1970 suggest that it was common knowledge among Hawaiians that Douglas was having an affair with Gurney's wife
Edith Scamman
(American, 1882-1907)
Born in Maine and received a B.A. and M.A. in literature from
Wellesley and Radcliffe. Her father died when she was young and
she spent much of the next 40 years caring for her mother and
doing local church work in Maine. After her mother's death, she
drove to Boston and enrolled in some botany classes at Radcliffe.
She was 53 years old! A favorite professor, Merritt Fernald, got
her interested in the plant distributions of unglaciated Alaska
and in 1936 she made the first of 9 trips to Alaska to collect
plants. During the next 30 years she made collecting trips to
Alaska, Central America, Iceland and the Caribbean. She made over
5000 collections of Alaskan specimens which she gave to the Gray
Herbarium at Harvard. Two Alaskan plants (which she discovered)
now bear her name: Claytonia scammaniana and Oxytropis
scammaniana. She was active in the field until her 70's, then
continued to work at the Harvard Herbaria until her death at 85.
Eric Hultén
Swedish botanist took part in a
1920 expedition to Kamchatka and became interested in Beringian
plant distributions. He is credited with originating the term
"Beringia". Compiled the Flora of Alaska.
Jacob Peter Anderson
With Stanley Welsh made over 11,000
collections of Alaskan plants and also compiled a comprehensive
flora or the region.
Margaret Murie
Born in 1902 in Seattle, she moved
to Fairbanks in 1911. She was the first woman to earn a degree
from UAF (1924). With her husband Olaus, who was also a biologist,
she spent her life traveling throughout Alaska. Many of the plant
specimens she collected are housed in the UAF herbarium. She is
known as the "grandmother of conservation" and was one
of the founders of ANWR. In 1998 President Clinton awarded her
the National Medal of Freedom.