B. ligustrina DC. Prodr. 5: 421. 1836.
B. vitis-idaea Oliver. Trans. Linn. Soc. Bot. II, 2: 277. 1887.
B. roraimae Schomb. Fauna & Fl. Guy. 1078. 1848. Nomen nudum.
B. ptariensis Steyermark, Fieldiana Bot. 28: 624. 1953.
DeCandolle described simultaneously B. brachylaenoides, B. venulosa, and
B. ligustrina. Baker (in Mart. Fl. Bras. 63 I: 82. 1884) synonomized B. venulosa
under B. brachylaenoides, although he apparently did not see the Haenke specimen
upon which B. venulosa was based; the photograph of the type material
(F8178) indicates that Baker was correct, as do subsequent Peruvian collections
(Killip & Smith 25704, Spruce 4333). Subsequent authors of varieties of B.
venulosa (Hieronymus, Cuatrecases, Steyermark) without explanation did not
follow Baker's interpretation; isotypes of B. venulosa var. cuspidibracteata
Steyermark and B. venulosa var. oblanceolata Hieron. have been examined by us
and are certainly conspecific with B. brachylaenoides; whether they are sufficiently
distinct to be varieties is not germane to the present discussion. Typical
var. brachylaenoides has large broadly oblanceolate acute to shortly acuminate
leaves and a well-developed large panicle. Typical var. ligustrina has small,
narrowly to broadly oblanceolate obtuse, apiculate, often 1-3-mucronulate leaves, smaller stature, less well developed panicles, and fewer flowers per head (10-15 rather than 12-25). Many geographically uncoordinated intermediates exist; even the more typical specimens show little geographical correlation. Typical var.
bracbylaenoides is represented by Riddel 575, Glaziou 11047, 6610, Gardner
490, 778, all from southeastern Brazil; Schomburgk 1014, Maguire & Maguire
35084, 35179, 35359, 35447 from Venezuela; and the previously mentioned
Peruvian collections. Collections with varying degrees of intermediacy toward
var. ligustrina are: Gardner 4915, Miers 3624, Glaziou 11111, 11114, from southeastern
Brazil; Rusby 1490, Williams 1454, Bucbtien 258r Rusby 1579 from
Bolivia; and Pbelps & Hitchcock 446, Cardona 1976 from Venezuela. More or
less typical var. ligustrina is represented by: Riedel HI/73 and Glaziou 15088
from southeastern Brazil; Tate 285 from Bolivia; Steyermark 58725, 59928,
60123. Steyermark & Wurdack 337, 338, 339, 340, 773, Phelps & Hitchcock 398,
Maguire & Maguire 40439, Steyermark 74892, 75872, Maguire, Wurdack, & Bunting
37114, 37297, 37313, Pinkus 110, Steyermark 58796, Ouelch & McConnell 91,
and Tate 399, all from southern Venezuela and adjoining Brazil. The quantitative
characters used to distinguish B. ptariensis from B. vitis-idaea have no significance;
the degree of inflorescence-development varies greatly within the series
Steyermark & Wurdack 337-340, all collected within a very small area on Chimanta-
tepul. It is believed that the robust plants of var. brachylaenoides represent
a response to a sheltered environment as contrasted to the usually open
areas in which the diminutive plants of var. ligustrina grow, at least in the
Pacaraima cumbres. This study has been supplemented by a generous loan of
the Kew material of the taxa concerned.