Name: Gallium asprellum Michx.
Common Names: Rough bedstraw, kidney-vine, cleavers, clivers (1,7,12).
Etymology: Gala, the Greek word from which Galium is derived, means “milk”. Some species of Galium were used to curdle milk, thus giving the genus this name. The specific epithet, asprellum, means “slightly rough”, referring to the roughness of the leaves and stems (5,9).
Botanical synonyms: None found.
Quick Notable Features (4,6,9):
¬ Herbaceous plant with small hooked prickles that catch on clothing or fur
¬ Most leaves in whorls of 6
¬ Axillary and terminal panicles of small white flowers
¬ Paired, smooth, round capsules
Plant Height: Typically 0.5-2.13 m long (5,9,10).
Subspecies/varieties recognized (7):
G. asprellum var. dahuricum (Turcz. ex Ledeb.) Maxim.
G. asprellum var. fructohispidum Maxim.
G. asprellum var. lasiocarpum Makino
G. asprellum var. tokyoense (Makino) Nakai
G. asprellum var. typicum (Michx.) Maxim.
Most Likely Confused with: Other species of Galium (especially Galium aparine and G. verrucosum), Sherardia arvensis, and Mollugo verticillata.
Habitat Preference: Rough bedstraw prefers wet to moist habitats and it is considered an obligate wetland species. The species is found in swamps, wet thickets, calcareous fens, riparian zones, marshes, wet meadows, bogs, and wet disturbed habitats (1,3,6,10).
Geographic Distribution in Michigan: G. asprellum is widespread in Michigan, reported in every county in the Upper Peninsula, and most counties in the Lower Peninsula (1).
Known Elevational Distribution: The species grows between 0 and 300 m above sea level. The highest elevation reported was in Alger Co., MI (7).Complete Geographic Distribution: Native to eastern North America. In the United States, G. asprellum is found in every state east of Minnesota and north of North Carolina (except KY), and it was recently reported in Louisiana. In Canada, it is found in NB, NF, NS, ON, PE, and QC (3,13).
Vegetative Plant Description: G. asprellum is a perennial herbaceous plant growing from creeping rhizomes and producing 4-angled branched stems. The plant stems are erect, prostrate, or leaning on adjacent vegetation, often forming mats. The stems, the margins of leaves, stipules, and the abaxial side of the midribs are covered in retrorse (backward pointing) prickles or bristles. There are 2 opposite leaves and 2-4 leaf-like stipules that form a whorl of 4 to 6 apparent leaves: 6 on the main branches and stem, and sometimes 4 or 5 on branchlets. The leaves and stipules are elliptic to oblanceolate, apically cuspidate, basally attenuate, sessile, entire, 0.5-2.5 cm long, and 0.2-0.5 cm broad (5,6,8,9,17).
Climbing Mechanism: G. asprellum climbs by leaning on adjacent vegetation with the aid of its recurved bristles (9,14).
Flower Description: The small perfect flowers of G. asprellum (~ 0.3 cm broad) are borne in axillary and terminal panicles or cymes up to 1.9 cm broad that branch 1-3 times. The inflorescence is longer than the subtending leafy bracts, and the flowers are pedicellate. The calyx is unlobed and fused to corolla and filament bases as a hypanthium. The corolla is 4-parted, white, rotate, each lobe cuspidate and longer than wide. The 4 stamens have short filaments and exserted anthers. The bi-carpellate ovary bears 2 short styles with one capitate stigma each; the carpels bear one ovule each (2,5,6,8,9).
Flowering Time: May-September in northeastern U.S. and adjacent Canada (5,6,9).
Fruit Type and Description: The fruits of rough bedstraw are paired dry capsules. They are round, indehiscent, smooth (rarely appressed pubescent), black at maturity, and 1-2 mm long and 2-2.5 mm broad. Each capsule bears one seed (1,2,6,8,9).
Seed Description: Galium seeds are convex dorsally, concave proximally and enclose a curved embryo (8).
Dispersal Syndrome: No diaspore dispersal information was found in the literature for the species. Galium mollugo, however, also has smooth fruits, which are commonly dispersed by birds, water, or simply by gravity (16), G. asprellum is likely dispersed in a similar way, due the similarly smooth fruit and moist habitats. On the other hand, vegetative parts of G. asprellum are covered in recurved prickles that may attach to animal fur, which would carry the fruits along.
Distinguished by: Galium aparine, G. odoratum, G. triflorum, G. circaezans, G. lanceolatum, G. boreale, G. kamtschaticum, and G. pilosum all have bristly ovaries and fruits. The only climbing Galium species that grows in Michigan other than G. asprellum is G. aparine, which can be differentiated by the number of leaves and stipules per whorl (6-8) and their length (up to 8.9 cm long). G. asprellum has smooth ovaries and fruits, and there are usually 4-6 leaves/stipules per whorl, each up to 2.5 cm long. G. verum, G. album, and G. sylvaticum have smooth, mostly erect stems and 6-12 leaves/stipules per whorl while G. asprellum has stems covered in hooked prickles. G. verrucosum has fewer branches than G. asprellum, if branching at all, and its fruits are 3-4 mm long (only 1-2 mm long in G. asprellum). The remaining Galium ssp. in Michigan can be differentiated by the lack of a cuspidate apex on the leaves and stipules. Sherardia arvensis is herbaceous with whorled bristly leaves like Galium, however, its calyx is clearly lobed, and the corolla is blue or pink and funnelform. G. asprellum has an unlobed calyx, and the corolla is white and rotate. Mollugo verticillata is a creeping herb with whorled leaves but differs from G. asprellum by its spatulate basal leaves, flowers with a 5-parted calyx, no corolla, 3 or 5 stamens, and superior 3-carpellate ovary. G. asprellum does not have spatulate basal leaves, the unlobed calyx, 4 stamens, and 2-carpellate ovary are borne on a hypanthium, and the corolla is present and 4-parted (1,8).
Other members of the family in Michigan (number species): Cephalanthus (1), Diodia (1), Galium (19), Houstonia (4), Mitchella (1), Sherardia (1), Stenaria (1) (source 1).
Ethnobotanical Uses: The Choctaw use the whole plant as a diuretic, to treat measles, and to induce perspiration (11). Also known as “kidney-vine”, G. asprellum was used for kidney troubles by rural communities (12). During colonial times, the species was used to curdle milk to make English-style cheeses (15).
Phylogenetic Information: Galium asprellum is included in the Rubioideae subfamily of the Rubiaceae family, which is in the Gentianales order, a part of the Asterid I clade of Angiosperms. The Gentianales order includes 4 other families: Gentianaceae (closest to Rubiaceae), Loganiaceae, Gelsemiaceae, and Apocynaceae. Members of the Rubiaceae are mostly found in tropical climates, although the family is also represented in other climates and it is spread worldwide except for Polar Regions, and the Sahara and Gobi deserts (4).
Interesting Quotation or Other Interesting Factoid not inserted above: G. asprellum is a special concern species in Tennessee (3).
Regarding leaves and stipules of Galium: “There is little doubt that in any whorl the two opposite ‘leaves’, one at any rate of which subtends an axillary shoot, are the true leaves, while the other members at the same node are stipules. Thus, in the case of a six-membered whorl there are two leaves, each of which is provided with two stipules. Where only five or four ‘leaves’ occur in a whorl, it is usually understood that in the first case one, and in the second case both, pairs of stipules have undergone a concrescence [fusion]. If, however, more than six ‘leaves’ are present in a whorl, it is explained that one or more of the original four stipules have undergone chorisis [division during development], resulting in the production of supernumerary members” (17).
Literature and websites used:
- Michigan Flora Online. A.A. Reznicek, E.G. Voss, & B.S. Walters February 2011. University of Michigan. December 28, 2013. http://michiganflora.net/species.aspx?id=2581.
- Chayka, K. 2006-2013. Minnesota Wildflowers: Galium asprellum. http://www.minnesotawildflowers.info/flower/rough-bedstraw
- USDA, NRCS. 2013. The PLANTS Database (http://plants.usda.gov, 12/28/2013). National Plant Data Team, Greensboro, NC 27401-4901 USA.
- Stevens, P.F. Angiosperm Phylogeny Website. Version 13, December 2013 http://www.mobot.org/mobot/research/apweb.
- Robert W. Freckmann Herbarium 2013. Smilax Illinoensis. University of Wisconsin, Stevens Point. http://wisplants.uwsp.edu/scripts/detail.asp?SpCode=GALASP
- Radford, A.E., H.E. Ahles, & C.R. Bell 1968. Manual of the Vascular Flora of the Carolinas. Chapel Hill, North Carolina, USA: The University of North Carolina Press.
- Tropicos.org. Missouri Botanical Garden. 28 Dec 2013 <http://www.tropicos.org/Name/27902719>
- Britton, N.L. & H.A. Brown 1970. An Illustrated Flora of the Northern United States and Canada: Volume I. New York, NY: Dover Publications, Inc.
- Fernald, M.L. 1950. Gray’s Manual of Botany, 8thed. New York: American Book Co.
- Mohlembrock, R.H. 2010. Nelumbonaceae to Vitaceae: Water Lotuses to Grapes. USA: Southern Illinois University Press.
- Campbell, T.N. 1951. Medicinal plants used by Choctaw, Chickasaw, and Creek Indians in the early nineteenth century. Journal of the Washington Academy of Sciences 41(9): 285-290.
- Perkins, A.E. 1929. Colloquial names of Maine plants. Torreya 29(6): 149-151.
- Allen, C.M. 2013. Notes on the identification and distribution of the species of the genus Galium (Rubiaceae) in Louisiana. Journal of the Botanical Research Institute of Texas 7(1): 509-513.
- Dufour, A. 1902. Climbing plants of Ohio. Ohio Journal of Science 2(4): 197-200.
- Lumbard, L.H. 1920. Cleavers. The American Botanist 26(3): 95.
- Mersereau, D. & A. DiTommaso 2002. The biology of Canadian weeds. 121. Galium mollugo L. Can. J. Plant Sci. 83:453–466.
- Takeda, H. 1916. Some points in the morphology of the stipules in the Stellatae, with special reference to Galium. Ann Bot os-30(2): 197-214.
- Zomlefer, W.B. 1994. Guide to Flowering Plant Families. Chapel Hill: The University of North Carolina Press.
Image Credits (all used with permission):
- Image of climbing habit courtesy of Pete Curtis, Minneflora, http://minneflora.com/images/identified/full/rough-bedstraw-galium-asprellum-01.jpg
- Image of the underside of leaves and stem courtesy of Rob Routledge, Sault College, Bugwood.org http://www.forestryimages.org/browse/detail.cfm?imgnum=5475374
- Image of the plant apex with inflorescence courtesy of Russ Schipper http://michiganflora.net/image.aspx?img=13198&id=2581
- Image of flowers close-up courtesy of Rob Routledge, Sault College, Bugwood.org http://www.forestryimages.org/browse/detail.cfm?imgnum=5475372
- Image of fruits courtesy of Dennis Profant, http://fieldbioinohio.blogspot.com
- Species distribution map, derived from the Michigan Flora Online.
PRIMARY AUTHOR: Cristine V. Santanna with revisions and editing by John Bradtke and Robyn J. Burnham.
© Robyn J. Burnham
For additional information on Michigan Plant Diversity species accounts, please contact Robyn J. Burnham via email: rburnham“at”umich.edu