Delimiting Species Boundaries in Rosa Sect. Cinnamomeae (Rosaceae) in Eastern North America
SIMON JOLY and ANNE BRUNEAU
Systematic Botany (2007), 32(4): pp. 819–836
https://www.webdepot.umontreal.ca/Usagers/jolysi/MonDepotPublic/jolylab/pdf/Joly&Bruneau_2007_SystBot.pdf
1. Hypanthium glabrous........................................................................................... 2
2. Long and straight prickles present throughout the stems..................................... R. acicularis (MB)
2. Prickles absent from the stems or, if present, either short (bristles) or curved........................ 3
3. Infrastipular prickles stout and broad-based..........................................R. virginiana
3. Infrastipular prickles absent or not especially stout or broad-based............................. 4
4. Generally fewer than 2 hairs per mm2 on the abaxial leaf surface;
infrastipular prickles always absent on new stems;
bristles always present on new stems;
leaflets from 7 to 9 per leaf..................R. arkansana (MB)
4. Generally more than 2 hairs per mm2 on the abaxial leaf surface;
infrastipular prickles either present or absent on new stems;
bristles generally absent on new stems;
leaflets from 5 to 7 per leaf....R. blanda (MB) includes R. woodsii
1. Hypanthium with glands . .................................................................... 5
5. Bristles present on new branches............................................................ 6
6. Hairs present on the abaxial surface of the terminal leaflet...................................... 7
7. Infrastipular prickles present...................................................R. carolina
7. Infrastipular prickles absent . .................................................R. arkansana (MB)
6. Hairs absent on the abaxial surface of the terminal leaflet.................................R. nitida
5. Bristles absent on new branches............................................................. 8
8. Width of the terminal leaflet less than 9 mm . . ........................................R. foliolosa
8. Width of the terminal leaflet more than 9 mm . .............................................. 9
9. Hypanthium typically with more than 86 glands;
terminal leaflet oblong,
generally with more than 20 small teeth per margin..........................................................R. palustris
9. Hypanthium typically with fewer than 86 glands;
terminal leaflet ovate, elliptic or obovate,
generally with fewer than 20 teeth per margin..................................................... 10
10. Bristles absent on new stems;
auricles more than 3.8 mm long;
stipules more than 1.1 mm wide;
infrastipular prickles stout, broad based, and often curved......................R. virginiana
10. Bristles present or absent on new stems;
auricles less than 3.8 mm long;
stipules less than 1.1 mm wide;
infrastipular prickles slender and not especially broad based or curved ..............R. carolina
Glossary
Hypanthium = a cuplike or tubular enlargement of the receptacle of a flower, loosely surrounding the gynoecium or united with it (the thing that becomes the outside of the rose hip)
glabrous = smooth, hairless
glands = a plant structure which secretes one or more products. This may be located on or near the plant surface and secrete externally, or be internal to the plant and secrete into a canal or reservoir.
infrastipular - at the base of a node - on a stem the place where a bud occurs
auricle - small ear-like projection from the base of a leaf or petal.
abaxial - the underside