Eutaxia

Taxonomy

Eutaxia R. Brown In W. T. Aiton, Hortus Kew. ed. 2. 3: 16. Oct-Nov 1811.

Subfamily: Faboideae.
Phylogenetic Number: 3.24.26.
Tribe: Mirbelieae.
Group: Pultenaea.
Species Studied - Species in Genus: 4 studied; 10 in genus.

Description

Fruit: A legume; unilocular; 0.4–0.6 cm long; 0.25–0.3 cm wide; 0.1–0.25 cm thick; length less than twice as long as width; with deciduous androecial sheath; with deciduous corolla, or persistent corolla; with standard petal (and wings); with persistent calyx, or deciduous calyx; with calyx shorter than fruit; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; symmetrical, or asymmetrical; ovate; with 1 straight and 1 curved suture; widest near middle or D-shaped; not inflated; compressed, or flattened; without beak, or with beak; hooked; with solid beak the same color and texture as fruit; rounded at apex; aligned with longitudinal axis of fruit, or oblique with longitudinal axis of fruit; rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous; seed chambers externally invisible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; substipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; passive. Replum invisible. Epicarp dull; monochrome; reddish to dark reddish brown; with surface texture uniform; pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent; with pubescence gray; with pubescence uniformly distributed; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not smooth; with elevated features; veined; reticulately veined; not tuberculate; not exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; thin; surface not veined; 1-layered; without balsamic vesicles; without fibers; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome; reddish tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1, or 2; length parallel with fruit length; neither overlapping nor touching, or overlapping and touching; in 1 series. Funiculus 0.5–1 mm long; of 1 length only; filiform, or thick; straight. Aril present; fleshy; when fleshy topknotlike; entire; covering less than 1/2 of seed; yellow.

Seed: 2.2–2.7 mm long; 1.5–2 mm wide; 1–1.5 mm thick; not overgrown; not angular, or angular (somewhat); asymmetrical; mitaform; compressed; with surface smooth; with visible radicle and cotyledon lobes; without external groove between radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; dull; not modified by a bloom; colored; monochrome, or mottled and streaked; with frequent mottles; with frequent streaks; brown to reddish brown; with brown overlay (dark reddish), or tan overlay; glabrous; smooth, or not smooth; with elevated features; reticulate; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; partially concealed; concealed by aril and radicle lobe, or wing; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; punctiform; between cotyledon and radicle lobe; flush; within rim; rim color lighter than testa (reddish). Lens discernible; with margins straight, or curved; somewhat wedge-shaped; elliptic; not in groove of raphe; confluent with hilum; mounded; similar color as testa; darker than testa; brown; not within corona, halo, or rim. Endosperm present; thin; not pluglike and not resembling tip of radicle; covering entire embryo; adnate to embryo. Cotyledons smooth; both outer faces convex; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; not concealing radicle; split over radicle; with lobes; with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis deflexed; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; lobe tip straight; deflexed and parallel to cotyledon length; centered between cotyledons; 1/2 to nearly length of cotyledons. Plumule rudimentary; glabrous.

Distribution

Southern Australia.

Old World; Australia (southern).

Generic Notes

Crisp et al. (1999) performed cladistic analyses using morpholgical and DNA characters with an ingroup consisting of one species of Almaleea (3.24.24), one of Aotus (3.24.21), two of Dillwynia (3.24.25), one of Euchilopsis (3.24.20), one of Eutaxia, one of Latrobea (3.24.18), one of Otion (a projected new genus), one of Phyllota (3.24.19), six of Pultenaea (3.24.23), and one of Urodon (3.24.22). They concluded that Pultenaea neurocalyx N.S. von Turczaninow and Pultenaea selaginoides (J.D. Hooker) M.D. Crisp & P.H. Weston are more closely related to Eutaxia and Almaleea, respectively, than they are to Pultenaea. Pultenaea neurocalyx is being separately studied by J. Chappill and G. Henderson.

Tribal Notes

Tribe Mirbelieae

Crisp and Weston (1987) analyzed the Mirbelieae, and we are following their species counts. We did not treat the following new taxa of Crisp and Weston: the Pultenaea incurvata A. Cunningham group of five species; Pultenaea neurocalyx P.K.N.S. Turczanivow, a one species group; Aotus phyliocides G. Bentham, a one species group; and, Oxylobium microphyllum G. Bentham, a two species genus. The genus Cupulanthus J. Hutchinson is listed on page 85 of Crisp and Weston (1987) and not mentioned by them again. Crisp and Weston (1995) have continued their phylogenetic studies of Mirbelieae, and proposed two major generic changes, the resurrection of Podolobium R. Brown with six species of Oxylobium (24.09, see Notes for Oxylobium) and a new genus, tentatively to be named Otion. Otion, as projected, will have six species, two new ones and four from four different genera: Aotus phylicoides G. Bentham, Burtonia simplicifolia F.J.H. von Mueller & R. Tate, Oxylobium microphyllum G. Bentham, and Phyllota luehmannii F.J.H. von Mueller.