Sigmoidala J.Compton & Schrire, 2019

Compton, James A., Schrire, Brian D., Koenyves 3, Kalman, Forest, Felix, Malakasi, Panagiota, Sawai Mattapha, & Sirichamorn, Yotsawate, 2019, The Callerya Group redefined and Tribe Wisterieae (Fabaceae) emended based on morphology and data from nuclear and chloroplast DNA sequences, PhytoKeys 125, pp. 1-112 : 35-36

4. Sigmoidala J.Compton & Schrire gen. nov.

Diagnosis.

The monospecific Sigmoidala kityana has several affinities with Endosamara racemosa including the absence of bracteoles and glabrous ovaries, characters which also separate it from Callerya s.str. which has bracteoles and sericeous ovaries. Sigmoidala also shares with Endosamara the pubescent floral bracts and broadly campanulate, slightly oblique, subtruncate calyx as noted by Schot (1994: 25) but it was placed in Callerya on account of the fruits that lacked the lomented endocarp. The stipules in Sigmoidala are shorter, 3-7 mm long (vs. 9-12 mm in Endosamara ); pedicels shorter, 3-4 mm long (vs. 4-12 mm in Endosamara and Sarcodum ), floral bracts linear, 6-8 mm long (vs. linear-lanceolate, 8-12 mm long in Endosamara , 6-20 mm in Sarcodum ); the back of the standard densely, appressed rufous pubescent (vs. glabrous in Endosamara and Sarcodum ) and the wing petals of Sigmoidala are unique within Tribe Wisterieae being a sigmoid shape, reflexed at the midpoint and extending outwards towards the apex (see Fig. 3I ). The pods of Sigmoidala are flattened, linear to obovate, 7-11 × 1-2 cm (vs. septate, flattened, linear, 10-25 × 1-2 cm in Endosamara and botuliform in Sarcodum ).

Type species.

Sigmoidala kityana (Craib) J.Compton & Schrire ≡ Millettia kityana Craib.

Genus description..

robust, twining woody vine. Stems very dark green when young, terete. Leaves evergreen, coriaceous and nitid when mature, imparipinnate with 7-9 (- 11) leaflets, rachis 12-30 cm long. Stipules 3-7 mm long, narrowly deltoid, persistent. Stipels 3-6 mm long, linear, persistent. Leaflets 7-18 × 2-5 cm, elliptic to narrowly obovate, glabrous above and below, apex cuspidate, margins entire, base cordate. Inflorescence a robust many-flowered terminal panicle 20-50 cm long, peduncle sparsely hairy. Flowers 16-20 mm long, emerging from August - November. Floral bracts 6-8 mm long, caducous, linear. Bracteoles absent. Pedicels 3-4 mm long, glabrous. Calyx 4 × 6 mm, campanulate, green, densely puberulent externally, five lobed, lobes ± equal 1-6 mm long, rounded, obtuse or subtruncate becoming subentire after anthesis. Standard 10-12 × 12-13 mm, suborbicular, inner surface white with a pink flush, nectar guide broad, deep golden-yellow, back of standard densely appressed, ferrugineous or rufous pubescent, apex acute or emarginate. Callosities of boss type. Wing petals glabrous, longer than keel in length but notably sigmoid towards apex and thereby shortened, each narrowly semi-pandurate 10-14 × 3 mm with basal claws 1-3 mm long. Keel petals 10-12 × 4-6 mm, glabrous, united into a long navicular cup, apex acute. Stamens diadelphous, nine fused together, the vexillary one free, all curved upwards at apex. Ovary glabrous, style glabrous, 3 mm long, curved upwards at apex, stigma punctate. Pods 7-11 × 1-2 cm, flattened, linear to narrowly obovate, dehiscent, exocarp surface glabrous, speckled with small pustules, subseptate. Seeds 1 –5(– 8), ellipsoid or orbicular 12-14 × 12-13 × 13 mm, hilum 1.6-2 × 2 mm, elliptic. Fig. 3 C–D .

Figures

Figure 3. Sigmoidala kityana (Craib) J. Compton & Schrire. A Habit B young leaf C lower surface of leaf D leaflet detail of hairs E inflorescence F flower bud with bracteole and pedicel G calyx external surface H standard petal inner surface I wing petal J keel petal K staminal column lateral view L staminal column ventral view M stamen dorsal and ventral views N ovary lateral view O style and stigma P pod Q pod detail of surface R seed ventral view S seed lateral view (all from Clark 245). Drawn by Margaret Tebbs.