Rosa in Manitoba

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

Publicado por marykrieger marykrieger, 26 de julio de 2020

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