Arabis Hybrid Pollen
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Rock Cress Pollen From San Jacinto & San Bernardino Mts
Brassicaceae: Boechera = Arabis Apomictic Hybrid
 © W.P. Armstrong 9 May 2012      Polyploidy & Hybridization Images 


Herbarium specimen of rock cress previously identified as Arabis (cf. holboellii?).


Stamen and pollen from flower of Boechera (cf. holboellii?) apomictic hybrid.

  

  Wayne's Word Explanation For Apomixis  

The pollen grains of Boechera (cf. holboellii?) are approximately 21-25 micrometers (microns) in diameter. This corresponds in size to an apomictic hybrid. The upper left pollen grain shows an elongated aperture or colpus. The shape is spheroid to slighly ovoid, but not elliptical. See the following image:


The spheroid-ovoid pollen grains of Boechera (cf. holboellii?) in the above two images are approximately 21-25 micrometers (microns) in diameter. This corresponds in size to an apomictic hybrid. Images taken with an Olympus Compound Microscope and Sony V-3. Magnification 1000x.

Stage micrometer at 1000x magnification with Olympus Compound Microscope. The diameter of field of view (fov) is 0.184 millimeters (184 micrometers). This corresponds to a 0.46 millimeter fov at 400x magnification.

  Wayne's Word Table Of Relative Sizes Of Cells & Viruses  

Pepple Plains, Baldwin Lake Ecological Reserve, San Bernardino Mts
More Images Of Spherical Pollen From Triploid Boechera (Arabis) Hybrid

The following images of large, round pollen grains came from two pressed herbarium specimens previously identified as Arabis (cf. holboellii?). According to Thomas Stoughton, Rancho Santa Ana Botanic Garden, they are from a triploid hybrid, probably between the diploid Boechera (Arabis) retrofracta and an unknown parental hybrid with spherical pollen. The diploid B. retrofracta has smaller, ellipsoid pollen. The true B. holboellii also has ellipsoid pollen but is retricted to Greenland.

Pollen grains from two pressed herbarium specimens previously identified as Arabis (cf. holboellii?). Magnification 400x.

Large, round pollen grains from pressed herbarium specimen previously identified as Arabis (cf. holboellii?). The image cropped and desaturated with Photoshop. Magnification 400x.

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