Boechera collinsii
(Reflexed Rock Cress)

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Flora of North America recognizes two species - Boechera collinsii and Boechera retrofracta - that are very similar.  They differ in the pubescence of the proximal stem.  B. collinsii has both simple and 2-rayed trichomes, while B. retrofracta has only 2-8-rayed trichomes.  The following specimen was determined to be B. collinsii because the proximal stem was examined and photographed.


Lower Plant

Upper Plant


Proximal Stem


Basal Leaf Top


Basal Leaf Top


Lower Cauline Leaf Top


Lower Cauline Leaf Bottom


Upper Cauline Leaf Top


Upper Cauline Leaf Bottom


Basal Leaf Top Close-Up


Basal Leaf Bottom Close-Up


Flower Side


Flower Side, Sepals Removed


Single Petal


Stamens and Pistil


Pistil


Infructescence


Fruit

B. collinsii / B. retrofracta
(Reflexed Rock Cress)

Budd's Flora and Flora of Alberta do not distinguish between B. collinsii and B. retrofracta. Therefore the proximal stem was not examined or photographed in these older specimens.  As a result I cannot distinguish between the two species in these cases.  Budd's Flora uses the name Arabis retrofracta for all of B. collinsii and B. retrofracta, while Flora of Alberta uses the name Arabis holboellii for this group.  The notes in the web pages linked to below use the name Arabis holboellii.


Whole Plant in Ground

Lower Part of Plant


Upper Part of Plant


Whole Plant


Lower Third of Plant


Middle Third of Plant


Upper Third of Plant



Early Inflorescence 



Fruiting Inflorescence



Basal Leaf Top


Basal Leaf Bottom


Basal Leaf Top Close-Up


Basal Leaf Bottom Close-Up


Lower Stem Leaf Top


Lower Stem Leaf Bottom


Middle Stem Leaf Top


Middle Stem Leaf Bottom


Inflorescence


Flower Top


Flower Side


Silique