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Plant Highlight: Hechtia argentea
by Brian Kemble
About the genus
The genus Hechtia, belonging to the Bromeliaceae (the Bromeliad Family), is primarily native to Mexico, although its range extends into Texas in the north and into Central America in the south. The various species generally have rosettes of long tapering, sword-like leaves, and in most cases these are armed with sharp marginal teeth. While the leaves may sometimes be green, they are often flushed or blotched with red, or in other cases have a coating of pale scales that give them a silvery sheen. One particular species was named for its silver appearance: Hechtia argentea.
Area of occurrence
Hechtia argentea was named in 1884, and a plant brought to Kew Gardens in England even before that is still growing there today, after having flowered for the first time in 1870. Unfortunately, collection records indicating its place of origin have not survived, and bromeliad aficionados long sought to find out where it occurs naturally. Finally, a thriving population was discovered in Toliman Canyon in the state of Hidalgo, and plants are now established in cultivation.
About the plant
H. argentea grows as a single stemless rosette with up to 100 long narrow silvery leaves which spread horizontally so as to give the plant has a somewhat flattened appearance. The leaves are up to 2 feet long (60 cm), tapering gradually to a point, with sharp spines (up to a little over a quarter-inch long, or 7 mm) arrayed along the margins. The spines are white, pale yellow or pale brown, and though they sometimes stick straight out, they are often hooked. There is a dense coating of silvery-white scales on both the upper and lower leaf surfaces, and this is the source of the plant’s name (argentea = silvery).
About the flowers and seeds
This species is spring-flowering, with its peak at the Ruth Bancroft Garden being in May and June. As is usual in Hechtia, this is a dioecious species (having separate male and female plants). Male flowers have pollen, but are not able to set seed, while female flowers do not produce pollen and must have it brought from a male plant in order to make seeds. In either case, the rosette produces multiple long slender flower stalks, emerging from between the leaves and bending upward, with very short lateral branches bearing compact rounded clusters of small white flowers. While the inflorescence may be nearly vertical, it often bends to the side, sometimes arching out and extending laterally. On our plants at the Ruth Bancroft Garden, male inflorescences have been up to 43 inches long (109 cm), while female ones have been up to 48 inches long (122 cm). Plants of both sexes have similar-looking tight flower clusters, with the lowest clusters subtended by stiff narrowly triangular bracts up to .8 inch long (2 cm), while the bracts on the upper ones are considerably reduced. The individual flowers have 3 white cupped petals, clasped by 3 thick brown sepals, with their diameter being up to .2 inch (5 mm). The male flowers are pink-tipped at the bud stage, but pure white when they open, with the yellow pollen of the anthers visible within the cup. The female flowers are also tinged purplish-pink as buds, whitening as they open, but with a slight blush of lavender remaining on the pistils, and sometimes on the petal tips as well. There are three diverging stigma-lobes atop the pistils, ready to receive pollen if a pollinator should come by. The stalks of the inflorescences, as well as the bracts and sepals, have a coating of white scales that make them look fuzzy, but these are not so dense as to hide the darker color of the surface from which they arise. Female plants produce dry capsules with 3 carpels (seed chambers) that are oval with beaked tips, splitting open along a vertical seam at maturity to release the small brown winged seeds.
Relationship to H. glomerata
Hechtia argentea is closely related to Hechtia glomerata, which has a wide distribution from Texas to Guatemala, and some authors consider it to be just a form of that species. Certainly the two have similar-looking rounded heads of flowers, but it might be useful to point out some differences. First, H. argentea is a larger plant with more leaves (up to 100 leaves, with a length of up to 60 cm; vs. about 40 leaves, with a length of up to 40 cm, for H. glomerata). Also, H. argentea has solitary rosettes, while H. glomerata often forms clumps. Most obviously, the leaves of H. argentea are coated with silvery scales on both surfaces, while in H. glomerata these are found only on the undersides. (Here, however, it should be noted that on younger plants of H. argentea the coating on the upper surface may be only partial). The petals of H. argentea are also a little longer (7 mm, vs. 5 mm for H. glomerata). and the fuzzy white scales seen on the sepals of the former are not present on the latter.
