Ayensua uaipanensis (Maguire) L.B.Sm.[as Ayensua uaipanensis (Maguire) L B Smith]

Observations: —Ayensua uaipanensis [Maguire] L.B. Smith by J. BOGNER in J. Brom. Soc. 25(6): 215-9. 1975
This very interesting bromeliad was first described in 1957 as Barbacenia uaipanensis Maguire (Velloziaceae). Later on, in 1962, Dr. L. B. Smith transferred it to Vellozia, another genus of the Velloziaceae, and called it Vellozia uaipanensis (Maguire) L. B. Smith. When Dr. E. S. Ayensu studied the anatomy of this plant, his results demonstrated that it belongs not to the Velloziaceae, but to the Bromeliaceae. Later, with more adequate material, Dr. L. B. Smith described for the plant in 1969 a new genus, Ayensua L. B. Smith, and made the new combination Ayensua uaipanensis (Maguire) L. B. Smith. The genus is named in honor of Dr. E. S. Ayensu, of the Smithsonian Institution in Washington, D. C. It was first discovered by K. D. Phelps and C. B. Hitchcock on the Uaipan-tepui ( Tepui is an Indian word and means "table mountain.") on January 27, 1948. Ayensua is a monotypical genus and is placed in the sub-family Pitcairnioideae.
Ayensua uaipanensis grows only on the summit of Uaipan-tepui and Auyan-tepui in Estado Bolivar, Venezuela. These two tepuis are to be found in southern Venezuela in an area called La Gran Sabana. The natural habitat of Ayensua uaipanensis on Auyan-tepui has an altitude between 2,200 and 2.400 m at "El Libertador", but it is also reported growing at an altitude of 1,660 m in the western Auyan-tepui; the locality on the Uaipan-tepui is 1,900 m high. Thus, this species grows only at high elevations.
I visited the summit of Auyan-tepui in February, 1975, where this bromeliad is growing abundantly. The Auyan-tepui is one of the largest tepuis. It is a very typical one with a flat topped appearance and is surrounded by high vertical cliffs of rose to red colored sandstone. The summit is dissected by deep crevices and has swamps, streams, and areas with small forests and low vegetation. It has a summit area of 700 square kilometers, and its highest altitude measures 2,500 m. This tepui also has the highest waterfall in the world, the famous Salto Angel, which has a free fall of about 1,000 m.
Ayensua uaipanensis grows mostly in cushions on the accumulations of humus on the deeper parts of the sandstone at the summit. But it also is commonly found growing between rocks as well as on cliffs. The soil is very acid, peat-like, and very low in mineral contents. Ayensua uaipanensis grows together with Stegolepis (Rapateaceae), Paepalanthus (Eriocaulaceae), Xyris and Orectanthe (Xyridadeae), Cyrilla (Cyrillaceae), Tepuia and Notopora (Ericaceae), Brocchinia and Cottendorfia (Bromeliaceae), Heliamphora (Sarraceniaceae).
Ayensua uaipanensis forms cushions 30 to 60 cm high, plants caulescent; stems simple or few-branched, covered with the old, dry leaf-sheaths and only at the terminal part with complete leaves; roots stout. Leaf-blades very narrowly triangular, glabrous, 3-8 cm long, light green. Inflorescence central and sessile, capitate; floral bracts equaling or exceeding the flowers; flowers white; sepals and petals very similar to each other, stamens in two very unequal series; fruits subglobose.
Several plants were in flower in February, 1975. I sent living specimens of Ayensua uaipanensis to Germany, but they have been very difficult to grow. We cultivate them in a warm greenhouse in rough peat which is kept wet.
Ayensua uaipanensis (Maguire) L. B. Smith emend. L. B. Smith & R. W. Read. Phytologia 38(2): 137. 1977
Petalis ellipticis, late rotundatis, cum sepalis vix similibus.

J. Bogner, Journ. Bromel. Soc. 25: 215, fig- 1975.
VENEZUELA: BOLIVAR: Auyan-tepui, "El Libertador", forming cushions, 2400 m, Bogner 828 (M).

Bogner's color photo shows such different sepals and petals that it did not seem possible that it could be the same species as Ayensua uaipanensis. However, comparison of his collection with earlier ones showed that the difference was due to age. In the earlier ones the thin petals had shriveled until they closely resembled the sepals, a condition not previously known in the Bromeliaceae and now happily removed.

Edited from : Smith & Downs 1974. Pitcairnioideae (Bromeliaceae) in Flora Neotropica.