Bocoa ratteri H.E.Ireland

Ireland, H. (2007). Taxonomic Changes in the South American Genus Bocoa (Leguminosae-Swartzieae): Reinstatement of the Name Trischidium, and a Synopsis of Both Genera. Kew Bulletin, 62(2), 333-349. Retrieved from http://www.jstor.org/stable/20443359

Type

Brazil: Maranhão, 53 km from Loreto, J. A. Ratter 7762 (holotype K!; isotypes E!, UB).

Morphology General Habit

Tree about 2.5m tall, flowering with juvenile leaves

Morphology Trunk

DBH 20 cm

Morphology General Bark

Bark smooth, silvery-grey with small white horizontally elongated lenticels; young branchlets white pubescent, older branchlets glabrescent; stipules 2 - 3 mm long, 1 mm wide, triangular, densely ferruginous pubescent

Morphology Leaves

Mature leaves not seen; young leaves with rachis 80- 142 mm long, densely white sericeous; petiole 24 - 40 mm long; leaflets 5-6, alternate, ovate, apex acuminate, base rounded to cuneate, white sericeous above, densely grey sericeous to velutinous, beneath, 70 - 84 mm long, 22 - 23 mm wide, attached to the petiolule ventrally; petiolules 4- 5 mm long, 1.5 - 2 mm wide, densely white sericeous, the costa not raised above, prominent beneath, the lateral veins reticulate, not raised above and obscured by the indumentum beneath

Morphology Reproductive morphology Inflorescences

Inflorescence racemose, 50 135 mm long, the axis densely white pubescent; floral bract 2 - 2.5 mm long, linear, densely white pubescent externally, glabrous internally, bracteoles absent; pedicel 5 - 6.5 mm long, densely white pubescent

Morphology General Buds

Buds 5-6 mm diameter, subglobose

Morphology Reproductive morphology Flowers

Flower with calyx splitting irregularly, the segments recurved, white pubescent externally, glabrous internally; stamens 50 65 in bud, many are caducous when the flower is open, when the number of stamens is reduced to 20 - 35, anthers 1 mm long, 0.5 mm wide, pale creamy-yellow, splitting longitudinally, filaments c. 10 mm long, waxy white, ovary with one or occasionally two free carpels, glabrous, stipe c. 2 mm long, style subulate, 2 - 3 mm long.

Distribution

Maranhão, Brazil.

Ecology

In tall, undisturbed, open canopy cerrado with trees to about 13 - 14 m, on a high plateau (shepada). No other trees of this species were observed in the vicinity.

Note

Alternate leaflets are uncommon within the Swartzia group (Ireland et al., 2000) of the tribe Swartzieae (which is comprised only of Swartzia and Bocoa sensut sticto), and are only otherwise known in two species of Swartzia; S. microcarpa Spruce ex Benth. and S. alternifoliolata Mansano. Bocoa ratteri has dorsifixed anthers, however, which are a synapomorphy for Bocoa and distinguish it from Swartzia. This species was included in the cladistic analysis of trnL sequences by Ireland et aL (2000) (as Swartzia sp. nov.), and it emerged in a strongly supported clade with Bocoa viridiflora and Swartzia species. Relationships within the clade, however, were not resolved. This species is only known from the type collection. Moreover, the fruit is unknown, and the leaves differ from the other two species in the genus. It is therefore placed in Bocoa with some trepidation, but since it matches Bocoa in floral characters, it is best placed here at least until further material becomes available. This species is named in honour of James Ratter, who has worked on the identification and surveying of Brazilian cerrado vegetation for more than 45 at the Royal Botanic Garden Edinburgh. His work has provided valuable information for establishing priority areas for conservation in this endangered and often overlooked habitat. He collected the type specimen of this species, and provided much of the information for the description.