A little background

Identifying Native Bamboo

Margaret C. Cirtain, Department of Biological Sciences, University of South Carolina, Columbia, SC

While many of the bamboos (grass family, Poaceae) found in the southeastern United States are invasive, non-native species, they may be distinguished from the native species fairly readily. One of the most aggressive non-native species is golden bamboo, Phyllostachys aurea. The stand shown in Figure 1 is typical of those found in the landscape across much of the United States and Figure 2 shows another Phyllostachys species.

Figure 1: Stand of golden bamboo found along Highway 72 near Corinth, MS.

Figure 2. Stand of Phyllostachys makinoi in North Carolina near the Joyce Kilmer Memorial Forest.

Golden bamboo, as well as other bamboos in the genus Phyllostachys, were introduced as ornamental plantings as early as the mid-1800’s throughout the US. This species is found along the Broad River in Columbia, SC. Another common introduced ornamental was Pseudosasa japonica, or arrow bamboo, and is shown in Figure 3.

Figure 3. Arrow bamboo commonly found in midtown Memphis, TN.

The bamboo species native to the southeastern United States are Arundinaria gigantea (river or giant cane), A. tecta (switch cane), and A. appalachiana (hill cane). They are very rarely found in urban areas and most often in rural areas with little disturbance, for example along stream banks and field and fence edges. They are also often understory plants in forested landscape and an excellent example of this is in Congaree National Park (Figure 4).

Figure 4. Switch cane is a common understory component of the Congaree National Park forest.

Historically, native bamboos formed extensive canebrakes, often stretching for miles and so dense that early travelers and explorers would detour around them. Many animals used these canebrakes as habitat, foraging and nesting within the thick, protective canes. The diversity of canebrake dwellers was large, from many invertebrate species including butterflies and moths, to avian species (Swainson’s warbler), reptiles (canebrake rattler), and mammals (black bear, swamp rabbit) (Platt et al 2001). The canebrakes have declined rapidly and are currently considered an endangered ecosystem (Noss et al 1995). This has had a negative impact on these faunal species with some being extirpated or extinct, as well as ecosystem services provided by canebrakes. Researchers have found river cane improves water quality from agricultural runoff and reduces erosion on stream banks and road sides (Dattilo and Rhoades 2005; Schroonover et al 2003, 2006), two critical ecosystem services (Figure 5).

Figure 5. River cane found along a stream bank, Coldwater River in northern Mississippi.

Distinguishing the Arundinaria spp. from non-native species and between the species is most easily seen in differences in distribution and vegetative characteristics. Typically switch cane is found in coastal plains and lower elevations, hill cane in higher elevations (Appalachian Mountain region), and river cane more widely distributed in the southeastern US (Triplett et al 2006; Triplett 2010).

The morphological characteristics of the bamboos are unique and bear identifying, particularly the culm, or stalk. The underground root system is primarily composed of segmented rhizomes with smaller roots extending from the rhizomes. Bamboos are divided into two rhizomal types, pachymorph or clumping, and leptomorph or running. The aboveground structure or culm and branches, is composed of segmented components consisting of solid nodes and hollow internodes. Branching (monopodial, one main axis with secondary arising from it) arises from axillary buds at the node on alternating positions along the culm. Bamboo bud or branch grouping at the node is called a branch complement. The number of branches and array pattern of the branch complement is a useful means of species identification, typically at midculm. There are two types of bamboo leaves, culm and foliage. The culm leaves form protective sheaths around the culm; the primary function of foliage leaves is photosynthesis. The uppermost leaves on the culm may help in identification, although variation in individuals makes this less reliable. Bamboos rarely flower, primarily propagating vegetatively. It has been estimated that Arundinaria spp. flower at 20 – 30 year intervals and seed is often not viable (Figure 6). Much of this as well as additional information can be found in two excellent sources, American Bamboos by Judziewicz et al and Bomboos for Gardens by Meredith.

Figure 6. Flowering Arundinaria gigantea

All three Arundinaria species have leptomorphic rhizomes differing only in presence (switch cane and sometimes in hill cane) or absence of air canals (river cane). River cane culms, or stems, are generally taller than the other species with a height from 2 to 8 meters with a slightly larger culm diameter. The branch complement characteristic for the Arundinaria spp. is one of the most useful in not only distinguishing among the three species, but from other bamboos as well (Table 1). Foliage is another distinguishing characteristic between the three species with hill cane having papery, deciduous foliage leaves, switch cane and river cane with leathery, persistent foliage leaves. There are generally fewer (6-8) and shorter (16-24 cm) leaves on the top branches of river cane than switch cane (9-12; 20-30 cm); hill cane (6-12; 9-22.5 cm) is similar to river cane (Triplett 2010).

Table 1. Morphological comparison of midculm branch complement (primary branch base) for Arundinaria appalachiana, A. tecta, and A. gigantea. Source: J. K. Triplett

          A. appalachiana                                    A. tecta                                     A. gigantea

2-5 unexpanded basal internodes

2-4 unexpanded basal internodes

0-1 unexpanded basal internodes

The Arundinaria canebrake ecosystem has been an important landscape component of the southeastern United States making restoration and reintroduction necessary for maintaining biodiversity. The canebrake ecosystem, particularly river cane, offers potential for restoration because of its ability to recover from wind and fire disturbance, supply much needed ecosystem services and soil stabilization, and provide habitat biodiversity. In light of the widespread, negative anthropogenic effects on the earth, the resulting loss of sustainability and imbalance to these ecosystems and associated systems would likely be minimized by restoring the damaged and declining canebrake ecosystem.

 Dichotomous Key for identification of ARUNDINARIA Michx. (Lynn G. Clark and J.K. Triplett)

1. Primary branches with 0–1 compressed basal internodes; culm internodes usually sulcate; culm leaves deciduous ... A. gigantea

1. Primary branches with 2–5 compressed basal internodes; culm internodes usually terete; culm leaves persistent to tardily deciduous ... 2

2. Foliage blades coriaceous, persistent, abaxial surfaces densely pubescent or glabrous, strongly cross veined; primary branches usually longer than 50 cm, basal nodes developing secondary branches; topknot blades 20–30 cm long ... A. tecta

2. Foliage blades chartaceous, deciduous, abaxial surfaces pilose or glabrous, weakly cross veined; primary branches usually shorter than 35 cm, basal nodes not developing secondary branches; topknot blades 9–22.5 cm long ... A. appalachiana 

1. Arundinaria gigantea (Walter) Muhl. (River Cane, Giant Cane)

Rhizomes normally remaining horizontal, sometimes hollow-centered, air canals absent.

Culms 2–8 m tall, to 3 cm thick; internodes typically sulcate distal to the branches.

Culm leaves deciduous; sheaths 9–15 cm; fimbriae 2.2–7 mm; blades 1.5–3.5 cm.

Topknots of 6–8 leaves; blades 16–24 cm long, 2–3.2 cm wide, lanceolate to ovate-lanceolate.

Primary branches to 25 cm, erect or nearly so, with 0–1 compressed basal internodes, lower elongated internodes flattened in cross section.

Foliage leaves: abaxial ligules usually ciliate, sometimes glabrous;

blades subcoriaceous, persistent, evergreen, 8–15 cm long, 0.8–1.3 cm wide, bases rounded, abaxial surfaces glabrous or pubescent, strongly cross veined, adaxial surfaces glabrous or almost so.

Spikelets 4–7 cm, greenish or brownish, with 8–12 florets.

Glumes unequal, glabrous or pubescent, lowest glumes obtuse to acuminate or absent;

lemmas 1.2–2 cm, usually appressed-hirsute to canescent, sometimes pubescent only towards the base and margins.

Caryopses oblong, beaked, without a style branch below the beaks. 2n = 48.

Arundinaria gigantea forms extensive colonies in low woods, moist ground, and along river banks. It was once widespread in the southeastern United States, but cultivation, burning, and overgrazing have destroyed many stands.

2. Arundinaria tecta (Walter) Muhl. (Switch Cane)

Rhizomes normally horizontal for only a short distance before turning up to form a culm, hollow-centered, air canals present.

Culms usually shorter than 2.5 m tall, to 2 cm thick; internodes terete in the vegetative parts.

Culm leaves persistent to tardily deciduous; sheaths 11–18 cm; fimbriae 1.5–8.5 mm; blades 2.5–4 cm. Topknots of 9–12 leaves; blades 20–30 cm long, 1.8–3.2 cm wide, lanceolate to ovate-lanceolate.

Primary branches usually 50+ cm, basally erect and distally arcuate, terete, with 3–4 compressed basal internodes, basal nodes developing secondary branches, lower elongated internodes terete in cross section.

Foliage leaves: abaxial ligules fimbriate to lacerate, sometimes ciliate;

blades 7–23 cm long, 1–2 cm wide, coriaceous, persistent, evergreen, bases rounded, abaxial surfaces densely pubescent or glabrous, strongly cross veined, adaxial surfaces pubescent.

Spikelets 3–5 cm, with 6–12 florets, the first occasionally sterile.

Glumes unequal, glabrous or pubescent; lowest glume obtuse to acuminate or absent;

lemmas 1.2–2 cm, glabrous or nearly so.

Caryopses oblong, beaked, a rudimentary hooked style branch present below the beak. 2n = unknown.

Arundinaria tecta grows in swampy woods, moist pine barrens, live oak woods, and along the sandy margins of streams, preferring moister sites than A. gigantea. It grows only on the coastal plain of the southeastern United States.

3. Arundinaria appalachiana Triplett, Weakley & L.G. Clark (Hill cane)

Rhizomes normally horizontal for only a short distance before turning up to form a culm, sometimes hollow-centered, air canals sometimes present.

Culms 0.5–1 (1.8) m tall, 0.2–0.6 cm thick; internodes terete.

Culm leaves persistent to tardily deciduous; sheaths 5.5–11 cm; fimbriae 1–4.6 mm; blades 0.8–1.4 cm.

Topknots of 6–12 leaves; blades 9–22.5 cm long, 1.4–2.8 cm wide, linear, linear-lanceolate, or ovate-lanceolate.

Primary branches usually shorter than 35 cm, erect, terete, with 2-5 compressed basal internodes, basal nodes not developing secondary branches.

Foliage leaves: abaxial ligules glabrous or ciliate, fimbriate or lacerate; blades 5–20 cm long, 0.8–2 cm wide, chartaceous, deciduous, bases rounded, abaxial surfaces pilose or glabrous, weakly cross veined, adaxial surfaces pilose.

Spikelets 3–5.5 cm, usually somewhat reddish purple, with 5–8 florets. 2n = unknown.

Arundinaria appalachiana grows on moist to dry slopes and in seeps. It is restricted to the southern Appalachians and upper piedmont.

References

Clark, L. G. and J. K. Triplett. 2010. Dichotomous key for Arundinaria Michx. http://herbarium.usu.edu/treatments/Arundinaria.htm.

Dattilo, A. J. and C. C. Rhoades. 2005. Establishment of the woody grass Arundinaria gigantea for riparian restoration. Restoration Ecology 13: 616-622.

Judziewicz, E.J., L.G. Clark, X. Londoño, and M.J. Stern. 1999. American Bamboos. Smithsonian Institution Press: Washington, D.C., U.S.A. 392 pp.

Meredith, T. J.  2001.  Bamboo for gardens.  Timber Press.  Portland, Oregon.

Noss, R. F., E. T. Laroe, III, and J. M. Scott.  1995.  Endangered ecosystems of the United States: a preliminary assessment of loss and degradation.  United States Department of Interior, National Biological Service, Biological Report 28, Washington, D. C., USA.

Platt, S.G., C.G. Brantley, and T.R. Rainwater. 2001. Canebrake fauna: wildlife diversity in a critically endangered ecosystem. The Journal of the Elisha Mitchell Scientific Society 117: 1-19.

Schoonover, J. E. and K. W. J. Williard. 2003. Ground water nitrate reduction in giant cane and forest riparian buffer zones. Journal of the American Water Resources Association 39: 347-354.

Schoonover, J. E., K. W. J. Williard, J. J. Zaczek, J. C. Mangun, and A. D. Carver. 2006. Agricultural sediment reduction by giant cane and forest riparian buffers. Water, Air, and Soil Pollution 169: 303-315.

Triplett, J. K., A. S. Weakley and L. G. Clark. 2006. Hill cane (Arundinaria appalachiana), a new species of bamboo (Poaceae: Bambusoideae) from the southern Appalachian Mountains. SIDA 22(1): 79-85.

Triplett, J. K. 2010. http://www.umsl.edu/~triplettj/

Zhu, Z., C-D. Chu, and C. Stapleton. 2006. Arundinaria. Pp. 113–115 in Z.-Y. Wu, P.H. Raven, and D.-Y. Hong (eds.). Flora of China, vol. 22 (Poaceae). Science Press, Beijing, Peoples Republic of China and Missouri Botanical Garden Press, St. Louis, Missouri, U.S.A. 653 pp. http://flora.huh.harvard.edu/china/mss/volume22/index.htm.

All images copyright M. C. Cirtain.

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