Angiosperm phylogeny

Tue Apr 27 18:00:19 CDT 1999

An update of our 'Angiosperm Families' package has been posted at the DELTA
Web site, at

               http://biodiversity.bio.uno.edu/delta/angio/

This version incorporates the classification of Flowering Plant Families
presented by The Angiosperm Phylogeny Group (APG) in Ann. Missouri Bot.
Gard. 85, 531-553 (1998). Their classification into ordinal and (informal)
supra-ordinal groups reflects recent, far reaching molecular phylogenetic
studies. It has appeared without group descriptions, but inclusion in our
package makes it easily accessible (along with earlier classifications) for
detailed research into morphological, phytochemical, etc., character state
correlations, and for preparing comparative group descriptions, via our
family descriptions in association with Intkey and other DELTA facilities.

The appended natural-language descriptions for the 'Asterids' and 'Rosids'
series of the APG's 'Core Eudicots' have been generated using Intkey and
Confor. To conserve space, they are restricted to a small suite of the
characters showing different tendencies in these two groups. They exemplify
the feasibility of preparing comparative descriptions via the present
package, and the opportunities available for researches into intra-group
variation by extended applications of Intkey to our descriptive data.
Ordinal descriptions may be expected to display less intra-taxon variability
than is apparent at this level.

The SUMMARY option of Intkey generates character-state distributions for any
grouping of families, using all the available characters or selected
character suites. This takes no more than a minute or two for any grouping
that is directly built into the current package, and preparing one for any
other series of families requires only that the user first selects their
names. Automatic conversion of the data into natural-language descriptions,
in RTF or HTML format, may be performed by applying Confor to the Intkey
output.

The following tables (obtained using Intkey) also compare the APG Rosids and
Asterids groups, our Tenuinucelli and Crassinucelli (this package, cf. Young
and Watson 1970) and Cronquist's (1966, 1981) subclasses, in terms of family
compositions.

______       Tenuinucelli Crassinucelli Unassigned
Asterids _____    98 _____      0 ______    2
Rosids  ______     0 ____     149 ______    0
Unassigned *1      2 _____     31 ______    2
Unassigned *2      8 _____     90 ______    6

_______      Asteridae Rosidae  Magnoli. Hamamel. Caryophyll. Dilleni.
Asterids _____  46 __     29 ______ 1 _____  1 ______  0 _______ 23
Rosids  ______   0 __     88 ______ 1 _____ 18 ______  0 _______ 42
Unassigned *1 _  0 __     10 ______ 0 _____  2 ______ 15 _______  8
Unassigned *2 _  0 __     25 _____ 39 _____  7 ______ 15 ______  18

*1 APG Core Eudicot but neither Rosid nor Asterid
*2 APG Oddment family, or basal order, or family of uncertain position at
the highest group level; or Eudicot but not core Eudicot; or core Eudicot
but neither Rosid nor Asterid

The first table shows that the APG Asterids are to all intents and purposes
the Tenuinucelli, while their Rosids are the Crassinucelli minus 19 families
they assign to 'basal orders' and numerous others they leave unclassified.
The Asterids also compare quite well with the Sympetalae (Metachlamydeae,
Gamopetalae) of Nineteenth Century systems (e.g. Bentham and Hooker, 1883;
Engler and Prantl, 1892), while the Rosids are recognisable as a restricted
version of Engler's Archichlamydeae.

By contrast, the second table shows how poorly the APG groupings compare
with the pseudo-phylogenetic subclasses Asteridae, Rosidae, Dilleniidae,
etc., and the two tables clearly demonstrate that 'Asterids' and 'Rosids'
are infelicitous names. When the impending, overhauled classification of the
Flowering Plants is formalised, it would surely be appropriate to
acknowledge nomenclaturally the astuteness of the Nineteenth Century
taxonomists who detected important groups without the benefits of embryology
and molecular biology, and with little or no regard for evolution.

A statement on the research applications for which the 'Angiosperm Families'
package was specifically designed may be seen in the introductory paper
(Watson and Dallwitz 1992). These included "monitoring the taxonomic
effectiveness of classifications derived from nucleic acid sequencing", the
appearance of which was then assumed to be imminent. The classificatory
components of the package are discussed in the Character Notes accompanying
#513 et seq., which may be read in the HTML version of the character list or
accessed via Intkey. Relevant references are included in the package.

SAMPLE DESCRIPTIONS.

Where not all families of a group are recorded for a character, fractions
indicate 'number of families for which the character state is recorded / the
number for which the character is recorded (known) and applicable'.
Intrafamilial variation results in the sum of the numerators of all the
states of a character exceeding the denominator. These examples incorporate
minor editing of the CONFOR output, to emphasize the more obvious
inter-group differences.

ASTERIDS (100 families)

Leaves stipulate (17), or EXSTIPULATE (96). Flowers tricyclic (3/75), or
TETRACYCLIC (70/75), or pentacyclic (12/75), or polycyclic (4/75). Free
hypanthium present (14/86), or absent (81/86). Hypogynous disk extrastaminal
(1/11), or astaminal (11/11). Perianth with distinct calyx and corolla (95),
or sequentially intergrading from sepals to petals (1), or sepaline (13), or
petaline (7), or vestigial (2), or absent (3). Corolla polypetalous (43/96,
but then often only occasionally so), or partially gamopetalous (1/96), or
GAMOPETALOUS (72/96); unequal but not bilabiate (23/81), or bilabiate
(25/81), or regular (70/81). Androecial members free of the perianth
(53/98), or adnate (64/98). Staminodes (when present)  external to the
fertile stamens (3/20), or in the same series as the fertile stamens
(17/20), or internal to the fertile stamens (1/20). Stamens 1-9-'many';
alternating with the corolla members (50/56), or opposite the corolla
members (4/56), or both alternating with and opposite the corolla members
(5/56).

Pollen grains 1-4-40 aperturate. Gynoecium 1-4-'many' carpelled. Ovules
UNITEGMIC (71/82), or bitegmic (14/82); TENUINUCELLATE (73/80), or
crassinucellate (13/80), or pseudocrassinucellate (2/80). Outer integument
(when present) contributing to the micropyle (3/13), or NOT CONTRIBUTING TO
THE MICROPYLE (10/13). Endosperm formation CELLULAR (56/74), or nuclear
(22/74), or helobial (1/74). Embryo chlorophyllous (11/42), or
achlorophyllous (35/42).

Iridoids detected (52/85), or not detected (33/85). Ellagic acid present
(9/70), or absent (65/70).

ROSIDS (149 families)

Leaves stipulate (98/148), or exstipulate (92/148). Flowers tricyclic
(6/69), or tetracyclic (42/69), or PENTACYCLIC (40/69), or polycyclic
(15/69). Free hypanthium present (54/121), or absent (84/121). Hypogynous
disk extrastaminal (17/38), or intrastaminal (26/38). Perianth with distinct
calyx and corolla (120), or sequentially intergrading from sepals to petals
(3), or sepaline (53), or petaline (5), or of 'tepals' (1), or vestigial
(14), or absent (16). Corolla (when present) POLYPETALOUS (115/119), or
partially gamopetalous (3/119), or gamopetalous (36/119, but then often only
slightly or rarely so); unequal but not bilabiate (19/83), or regular
(72/83). Androecial members free of the perianth (132/140), or adnate
(27/140). Staminodes (when present) external to the fertile stamens (17/28),
or in the same series as the fertile stamens (8/28), or internal to the
fertile stamens (9/28). Stamens 1-21-'many'; alternating with the corolla
members (14/39), or opposite the corolla members (9/39), or both alternating
with and opposite the corolla members (24/39).

Pollen grains 2-5-'many' aperturate. Gynoecium 1-5-'many' carpelled. Ovules
unitegmic (13/121), or BITEGMIC (114/121); tenuinucellate (14/112), or
CRASSINUCELLATE (103/112). Outer integument (when present) CONTRIBUTING TO
THE MICROPYLE (68/85), or not contributing to the micropyle (36/85).
Endosperm formation cellular (6/98), or NUCLEAR (94/98), or helobial (3/98).
Embryo chlorophyllous (40/61), or achlorophyllous (31/61).

Iridoids detected (4/83), or not detected (80/83). Ellagic acid present
(40/94), or absent (70/94).

Dr. Les Watson
78 Vancouver Street            Email: lesw at albanyis.com.au
Albany, WA 6330, Australia     Phone: +61 898 41 6181