Acacia hindsii × cochliacantha
Creators: name: David S. Seigler
name: John E. Ebinger
Publisher: name: Zenodo
Year: 1995
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Fabales
Fabaceae
Acacia
Acacia hindsii × cochliacantha

description: Acacia hindsii x A. cochliacantha.
Acacia x gladiata Saff., J. Wash. Acad. Sei. 5: 359. 1915. Myrmecodendron gladiatum (Saff.) Britton & Rose, N. Amer. FI. 23: 92. 1928. TYPE: Mexico. Sinaloa: vicinity of Rosario, 1849, J. Gregg 1135 (holotype, MO; photo, F, NY; fragment and photo, US).
Shrub or small tree to 4 m tall, twigs dark reddish brown, nearly glabrous. Stipular spines light brown to reddish brown, glabrous, flattened (sometimes oval in cross section), symmetrical, widely spreading with an angle of 160 to 180°, linear-lanceolate, constricted toward the base, to 60 mm long, 5-13 mm wide. Leaves 70-130 mm long; pinnae 8-16 pairs per leaf, 15-35 mm long, 5-10 mm between pinna pairs; rachis puberulent, a columnar gland with a depressed apex located near the node between each pinna pair (sometimes absent); petiole grooved, puberulent, 7-10 mm long. Petiolar glands columnar to volcano-shaped, 1-2 scattered along the petiole, glabrous, striate, apex 0.4-1.5 mm across. Leaflets 14-20 pairs per pinna, glabrous, linear, 2.5-4.5 mm long, 0.7-1.2 mm wide, one vein from the base, lateral veins not obvious. Inflorescence a loosely flowered, cylindrical spike, 8-17 mm long, 3.5-5 mm thick, in clusters of 2-6; peduncles to 13 mm long, puberulent; involucre located at or above the middle of the peduncle, 4-lobed, puberulent. Floral bracts spatulate. Flowers sessile; calyx 0.6-0.9 mm long, the lobes puberulent; corolla puberulent, maroon, 5-6-lobed, about twice as long as the calyx. Fruits not seen.
Representative specimens. MEXICO. Oaxaca: 3 mi. N of Puerto Escondido, Seigler et al. 11566 (ILL). Sinaloa: 14.4 mi. NW of Rosario on hwy. 15, Janzen 1720 (EIU, ILL), Ortega 4884 (US).
The narrow cylindrical inflorescences, the small leaflets, and the presence of rachis glands indicate that A. hindsii is the ant-acacia parent, while the enlarged, flattened stipular spines suggest that A. cochliacantha is the non-ant-acacia parent. In many of its characteristics this hybrid is intermediate between the parents. The large, compressed stipular spines are similar to those of A. cochliacantha, although these spines are not spoon-shaped as in typical A. cochliacantha. No specimens were found on which the spines exhibited the characteristic entrance holes made by acacia-ants. Overall, the leaves are similar to those of A. cochliacantha in that they are relatively short and narrow. The leaflets, however, are similar to those of A. hindsii, being 3.0- 4.5 mm long and 0.7-1.2 mm wide. In A. cochliacantha, in contrast, the leaflets are typically 0.8-2.4 mm long and 0.3-0.6 mm wide (Seigler & Ebinger, 1988). Furthermore, the presence of rachis glands indicates a relationship to A. hindsii, as does the presence of Beltian bodies on the lower 1-4 leaflet pairs of most pinnae.
description: Published as part of David S. Seigler & John E. Ebinger, 1995, Taxonomic Revision of the Ant-Acacias (Fabaceae, Mimosoideae, Acacia, Series Gummiferae) of the New World, pp. 117-138 in Annals of the Missouri Botanical Garden 82 on pages 136-137, DOI: 10.2307/2399983