1. Taggar röda, raka eller svagt snedställda.
2. Blomställning gleshårig nedtill.
3. Blad vackert hjärtlika.
4. Blad gles-täthåriga under, nästan gröna.
   
5. Blommor rent vita, även i knopp.
6. Fruktämnen kala men blombotten glest långhårig.
   
7. Blomställning med glandler (men årsstam mest utan).
8. Blad 3-5 delade.
9. Bladskaft längre än nedre småbladen.
10. Skaft på mellanblad ganska långt (~5 mm).
11. Bladnerver bruna på undersidan.
12. Bladkant enkelsågad, men taggar ofta ojämna (en liten, en stor).
13. Fruktsättning felslående.
14. Blomställning påfallande bladig.
15. Nedliggand växtsätt.
16. Årsstam utan eller med enstaka glandler.
17. Uddblad enkelsågade, breda (8-9.7 cm), lika långa som breda.
18. Blad stora, 20-22 cm.
19. Uddbladsskaft långt (3.3-3.8 cm), men med få  (3-4).
    

Utbredning
Känd från sju lokaler kring Buera i Onsala, Halland [Ryde:11]. Karta i Ryde:09.

Holotype (LD, isotypes: GB, S, UPS): Halland, Onsala: west side of the road at the bus stop Valldahemmet, Swedish Grid RT90 6374528 1177923, leg. U. Ryde., 30 Jun 2009 [Ryde:11].

Scannade ex från Hl, Onsala: Buera, 6374113 1267708, 2003-06-29:3;
Hl, Onsala, Landsvägens V sida vid busshållplatsen Valldahemmet, 6374528 1267923, 30/6-09.

Systematik
Denna art har uppstått ur hybriden R. antecedens x idaeus (Nord. J. Bot. 2021:e03111). Det är en självständig apomikisk art, men med liten utbredning.

Variation
Monströsa blommor förekommer.

Kromosomtal 2n = 35 [Ryde:11].

Description of type [Ryde:11]: The stem is procumbent, bluntly angled, 5-6 mm in diamerter, typically green, glabrous and with no or occasional glands. The internodes are ~10 cm. The prickles are patent to recurved, prominently red, also in the shade, ~13 per 5 cm, 3-5 mm, with a base of 3-4 mm. The sti- pules are 1-2 mm wide. The leaves are 20-22 cm long, with 3-5 leaflets, purely green. The leaf stalk is 7-9 cm, with 10-15 prickles that are 2-3 mm with a curved tip. The terminal leaflets are cordate, 8-10 x 8-10 cm, widest below the middle, and sparsely hairy on both sides; its petiolule is 3-4 cm, with ~4 prickles. The serration is simple with teeth of unequal size. The leaf apex is rather short, ~1 cm. The lateral leaflets are 8-9 cm long with a petiolule of 3-5 mm. The basal leaflets are 5-6 cm long with a petiolule of ~2 mm. The rachis is conspi- cuously leafy, sparsely hairy, and with rather few glands. The prickles in the inflorescence are recurved and 2-3 mm. The pedicels are 5-13 mm with ~3 prickles of ~1 mm that are recurved to slightly curved. The upper leaves are mostly three-lobed, coarsely serrate and grey beneath. The flowers are rather small, ~2 cm. The petals are purely white, also in bud. The filaments and styles are white. The sepals are grey-green with a white margin and sessile glands. They have short tips and are erect in the fruit. The hypanthium is sparsely hairy. The carpels are glabrous. The stamens exceed the styles and the anthers are glabrous. The fruits are usually aborted.

Bilderna i detta dokoment är thumbnails och länkar till 8x större bilder.