Douglas Justice contributed today’s write-up. Douglas writes:
Thanks to Alan Tracey for today’s image. Alan recently traveled to the Chilean Andes, where he took many photographs of fascinating and unusual plants. We hope to show a number of Alan’s excellent images over the next few weeks.
Chusquea (mountain bamboo) is a New World genus of woody, evergreen, semelparous (= monocarpic; i.e., once flowering) bamboos, native from northwestern Mexico and the West Indies, south to southern Chile and Argentina. They are differentiated from most other bamboos by their solid, pith-filled culms, although at least two species are reputed to have hollow culms. Chusqueas also typically have dimorphic branch buds at each node (there is usually one large central bud with smaller subsidiary buds arranged below and to the sides), and lack both fimbriae and auricles. Auricles are tiny outgrowths of the culm leaf sheath and are characteristic of many bamboos, while fimbriae, often called oral setae, are the bristle-like hairs associated with them. Nearly all species are reported to have pachymorphic (i.e., short, thickened and freely branching) rhizomes. Such rhizomes produce clumping, rather than running, bamboos. See Chris Stapleton’s Bamboo Identification page for an excellent primer on the subject of bamboo identification.
Chusquea culeou is the hardiest of its genus, but is still relatively rare in cultivation. It suffers badly from cold winters in the Vancouver area, as the exposed portions of the culms burn back when temperatures drop to anything less than minus 10°C for an extended time. This species is known as the foxtail bamboo because, in the most commonly cultivated forms, its multiple, leafy, nodal branches are thickly produced and are all approximately the same size. This creates a tufted, bottle-brush effect along the upper part of the culm. Another significant ornamental characteristic is the contrast between the bright green to dark brown culms and their persistent, papery straw-coloured sheaths, a feature most evident on the taller growing forms. The species is evidently quite variable, and in some places, grows to as much as 7.5 m tall. The mature plant pictured here, and those nearby (according to Alan) grow to only about 2.5 or 3 m tall.
A further notable characteristic of the species is that it is taxonomically confused. Some authors attribute this to the fact that chusqueas in the southern Andes are actively speciating. Add to this the fact that Chusquea culeou evidently flowered in a number of places in the early 1990s and copious amounts of seed were subsequently planted. These factors go a long way to explaining the variability within the species, the proliferation of names, and their sometimes contradictory descriptions. For an excellent profile of the genus, see “Chusquea — Mountain Bamboo of Latin America” (PDF) via the RHS journal, The Plantsman.