These notes were first published on the Taxacom Discussion List on 27 April 1999 — see http://usobi.org/archives/taxacom.html.
This package 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, comprehensive schemes) 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 further 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) 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.
Table 1
|
Tenuinucelli |
Crassinucelli |
Unassigned |
|
|
Asterids |
98 |
0 |
2 |
|
Rosids |
0 |
149 |
0 |
|
Unassigned *1 |
2 |
31 |
2 |
|
Unassigned *2 |
8 |
90 |
6 |
Table 2
|
Asteridae |
Rosidae |
Magnoliidae |
Hamamel. |
Caryophyll. |
Dilleniidae |
|
|
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
Table 1 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, Table 2 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 intrastaminal (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).