Senna dariensis var. gatunensis

  • Title

    Senna dariensis var. gatunensis

  • Authors

    Howard S. Irwin, Rupert C. Barneby

  • Scientific Name

    Senna dariensis var. gatunensis (Britton) H.S.Irwin & Barneby

  • Description

    14b. Senna dariensis (Britton & Rose) Irwin & Barneby var. gatunensis (Britton & Rose) Irwin & Barneby, comb. nov. Chamaefistula gatunensis Britton ex Britton & Rose, N. Amer. Fl. 23(4): 234. 1930.—Type from Gatun, November-December 1859, S. Hayes 548."—Holotypus, NY (2 sheets)!—Cassia fruticosa var. gatunensis (Britton & Rose) Schery, Ann. Missouri Bot. Gard. 38(1) [=F1. Panama 5(31)]: 81. 1951.

    Lf-rachis as long or commonly somewhat longer than petiole; venation of upper lft-face either immersed or prominulous but not or scarcely depressed, the lower face paler than the upper but not notably glaucescent; sepals of var. dariensis except more promptly deciduous; long petals 15-25 mm.—Collections: 29.

    Habitat of var. dariensis and sympatric with it in Canal Zone and (locally) Darien, but apparently commonest on the Caribbean slope of the Divide in San Bias, Panama, extending e. and s.-e. to Turbaco in Bolivar, Colombia and centr. Choco; one disjunct record from n.-e. Costa Rica (Heredia).—Fl. IV-XII, perhaps throughout the year.

    Very close to typical var. dariensis, indeed identical in the narrow pod, but differing not only in vesture, as overemphasized by Schery (1951), but also in the generally longer petioles, less impressed venation of the leaflets’ upper face, and deciduous sepals. Where var. dariensis and var. gatunensis cohabit, as near Gamboa on the Canal and on the Pacific slope in Darien, they are readily distinguished by these features and we have seen no doubtfully intermediate specimens. Our one record from Choco (White & Warner 99, MO) is unusual in the pallor of the dorsal leaf-venation and exceptionally short-beaked anthers; we lack the pod, necessary to confirm the identity. The var. gatunensis was encountered first by Humboldt and Bonpland, in ripe fruit in April, 1801, near Turbaco, Colombia, but the specimens (Bonpland 1425, P) were either not seen or ignored by Kunth when he was working up the Caesalpinioideae for Nova Genera & Species.