Arabis pycnocarpa var. adpressipilis

M. Hopkins

Rhodora 39: 117. 1937.

Synonyms: Arabis hirsuta var. adpressipilis (M. Hopkins) Rollins
Treatment appears in FNA Volume 7. Treatment on page 260. Mentioned on page 261.

Stems pilose, trichomes appressed, malpighiaceous, or minutely stalked, forked, plants rarely glabrescent. Basal leaves: blade surfaces pubescent, trichomes sessile, forked, and/or stellate. Fruits (4–)4.5–6(–6.5) cm; style 0.5–1.3 mm.


Phenology: Flowering Mar–Jun.
Habitat: Ravines, pastures, cliffs, calcareous talus, dolomite glades, rich woods, bluffs, rocky ledges
Elevation: 0-300 m

Distribution

V7 343-distribution-map.gif

Ont., Ill., Ind., Iowa, Kans., Mo., N.Y., Ohio, Pa., Tenn., Va.

Discussion

R. C. Rollins (1941, 1993) recognized both pycnocarpa and adpressipilis as distinct varieties of Arabis hirsuta; G. A. Mulligan (1996) treated adpressipilis as a synonym of A. hirsuta var. pycnocarpa. In my opinion, the differences in trichome morphology of the stems and leaves are significant enough to justify recognition of infraspecific taxa of one species.

Selected References

None.

Lower Taxa

None.
Ihsan A. Al-Shehbaz +
M. Hopkins +
Ont. +, Ill. +, Ind. +, Iowa +, Kans. +, Mo. +, N.Y. +, Ohio +, Pa. +, Tenn. +  and Va. +
0-300 m +
Ravines, pastures, cliffs, calcareous talus, dolomite glades, rich woods, bluffs, rocky ledges +
Flowering Mar–Jun. +
Arabis hirsuta var. adpressipilis +
Arabis pycnocarpa var. adpressipilis +
Arabis pycnocarpa +
variety +