Hovea

Taxonomy

Hovea R. Brown ex W.T. Aiton In W.T. Aiton, Hortus Kew. ed. 2. 4: 275. Dec 1812.

Subfamily: Faboideae.
Phylogenetic Number: 3.23.04.
Tribe: Bossiaeeae.
Group: Templetonia.
Species Studied - Species in Genus: 11 studied; ca. 20 in genus.

Description

Fruit: A legume; unilocular; 1.2 cm long; 2.1 cm wide; 0.35–0.5 cm thick; wider than long; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight; not plicate; not twisted; asymmetrical; circular (subcircular); with both sutures parallelly curved; not inflated; compressed; without beak; rounded at apex; aligned 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; nonstipitate; with all layers dehiscing; splitting along suture(s). Dehiscence of valves along both sutures; apical and down; active; with valves enrolling. Replum invisible. Epicarp dull; monochrome; brown; with surface texture uniform; glabrous, or pubescent and indurate; with hairs erect; with 1 type of pubescence; puberulent, or villous; with pubescence golden; with simple hairs; pliable; with hair bases plain; eglandular; without spines; not 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; tan; smooth; without adhering pieces of testa; nonseptate; chartaceous; not exfoliating; remaining fused to mesocarp and epicarp; without wings; entire. Seed(s) 1; length parallel with fruit length. Funiculus thick; curved. Aril present; fleshy, or dry (rarely); when fleshy cupshaped; entire; covering less than 1/2 of seed; when dry cupshaped; entire; covering less than 1/2 of seed; brown, or tan.

Seed: 4–6 mm long; 4–5 mm wide; 2–2.5 mm thick; not overgrown; not angular; asymmetrical; elliptic to oblong; compressed; without visible 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; brown; glabrous; smooth; coriaceous. Pleurogram absent. Pseudopleurogram absent. Fracture lines absent. Rim absent. Raphe visible; from hilum through lens to base of seed and terminating; not bifurcating; darker than testa. Hilum present; partially concealed; concealed by aril; with faboid split; with the lips of the faboid split the same color as the rest of the hilum; larger than punctiform; 2 mm long; with curved outline; elliptic; marginal according to radicle tip; flush; not within corona, halo, or rim. Lens discernible; with margins curved; circular; not in groove of raphe; adjacent to hilum; 1 mm from 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 testa. 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; partially concealing radicle; split over radicle; with lobes; with lobes touching (auriculate); with the interface division terminating at base of radicle; without margins recessed; yellow; inner face flat; glabrous on inner face. Embryonic axis straight; oblique to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; bulbose; oblique to cotyledons; centered between cotyledons; less than 1/2 length of cotyledons. Plumule moderately developed; glabrous.

Distribution

East to Southwestern Australia (Queensland to Tasmania).

Old World; Australia (Queensland to Tasmania).

Generic Notes

Polhill (1981n) listed ca. 12 species, Ross (1988) listed ca. 20 species, and we are following the latter count. Polhill (1976) provided a full page plate of external and internal seed characters of Hovea heterophylla A. Cunningham ex J.D. Hooker (now H. linearis (J. Smith) R. Brown). Valves of Hovea fruits curve inwardly from apex to base bringing both closer together because they are wider than they are long. These are unusual legume characters because most faboid valves curve inwardly from their sides leaving the apex and base in the same relative position and are usually much longer than wide. The seeds of Hovea species have a surprisingly large hilum. The hilum-seed length ratio is similar to the ratios seen in seeds of some genera in tribe Phaseoleae (10) and Lamprolobium (23.02).

Tribal Notes

Tribe Bossiaeeae

The Bossiaeeae with ten genera traditionally has been divided into two groups in part on fruit and seed characters. The Templetonia group with the first four genera (including at the time Lamprolobium, 23.02) has non-winged, coriaceous legumes and compressed seeds bearing a collarlike often-lipped aril (except Templetonia biloba (G. Bentham) R.M. Polhill), and a short, straight radicle. The Bossiaea group with the remaining genera has the legumes keeled to winged or not so, plump seeds often covered by a hooded caplike aril (lacking in Muelleranthus (23.08) and Ptychosema (23.09)), and a slender deflexed radicle exserted from the cotyledons. Crisp and Weston (1987, pages 105–107) in their cladistic analysis of the Bossiaeeae, Brongniartieae (22), and Mirbelieae (24), provided compelling evidence that the Bossiaeeae should be redefined to include only the Bossiaea group (genera 23.05–23.10). The Templetonia group would be moved to the Brongniartieae becoming genera three through eight, after Brongniarta (22.01) and Harpalyce (22.02). The proposed generic sequence would be: 3, Templetonia (23.01); 4, Lamprolobium; 5, Plagiocarpus (23.03); 6, ?Genus A (Templetonia incana J.H. Ross); 7, ?Genus B (Templetonia biloba (G. Bentham) R.M. Polhill); and 8, Hovea (23.04). They (Crisp and Weston, 1995) retracted their proposal to transfer the Templetonia group because of Chappill's (1995) cladistic analysis of the entire family, and we have used the traditional circumscriptions of the two tribes (Pohill, 1994a, 1994b).