Observations by johnrusk

Xanthoria parietina—maritime sunburst lichen. One of the most widely distributed of lichens, Xanthoria parietina is found on every continent except Antarctica usually not far from maritime influences. Found most often on wood substrates, particularly trees of the genus Populus, it also grows on rocks, walls, and roofs. Xanthoria parietina covers the trunks of quaking aspens (Populus tremuloides) on the west stide of the Regional Parks Botanic Garden. This lichen is often used as a biomonitor for atmospheric nitrogen. It has also been found to have antiviral properties, inhibiting the replication of human parainfluenza virus type 2, according to Wikipedia. Photographed at Regional Parks Botanic Garden located in Tilden Regional Park near Berkeley, CA

Xanthoria parietina—maritime sunburst lichen. One of the most widely distributed of lichens, Xanthoria parietina is found on every continent except Antarctica usually not far from maritime influences. Found most often on wood substrates, particularly trees of the genus Populus, it also grows on rocks, walls, and roofs. Xanthoria parietina covers the trunks of quaking aspens (Populus tremuloides) on the west stide of the Regional Parks Botanic Garden. Photographed at Regional Parks Botanic Garden located in Tilden Regional Park near Berkeley, CA

Rebutia pseudodeminuta—Scarlet Crown Cactus. A cactus with many names; a situation, unfortunately, not uncommon for cactus. The genus Rebutia is considered polyphyletic, but wide differences exist among taxonomists who have studied the genus. A 2011 study trying to make sense of DNA analyses renamed the species Aylostera buiningiana but the name is not widely accepted. The authoritative Plant List maintained by Kew uses Rebutia pseudodeminuta. Literature from 1972 and later, including the label for this specimen uses Rebutia buiningiana. Those interested in such matters should Google each of these three names plus the Botany 101-level Wikipedia article for the genus Rebutia. The species, widely available in the cactus trade, comes from Northern Argentina and adjoining Bolivia.

The flowers of this specimen measure 40 mm, the anthers & stamens together are 5 mm, and the spines are 5 mm (each pair of spines are thus 10 mm.)

The plant is located in a private cactus collection in Berkeley, CA.

Rebutia pseudodeminuta—Scarlet Crown Cactus. A cactus with many names; a situation, unfortunately, not uncommon for cactus. The genus Rebutia is considered polyphyletic, but wide differences exist among taxonomists who have studied the genus. A 2011 study trying to make sense of DNA analyses renamed the species Aylostera buiningiana but the name is not widely accepted. The authoritative Plant List maintained by Kew uses Rebutia pseudodeminuta. Literature from 1972 and later, including the label for this specimen uses Rebutia buiningiana. Those interested in such matters should Google each of these three names plus the Botany 101-level Wikipedia article for the genus Rebutia. The species, widely available in the cactus trade, comes from Northern Argentina and adjoining Bolivia.

The flowers of this specimen measure 40 mm, the anthers & stamens together are 5 mm, and the spines are 5 mm (each pair of spines are thus 10 mm.)

The plant is located in a private cactus collection in Berkeley, CA.

Rebutia pseudodeminuta—Scarlet Crown Cactus. A cactus with many names; a situation, unfortunately, not uncommon for cactus. The genus Rebutia is considered polyphyletic, but wide differences exist among taxonomists who have studied the genus. A 2011 study trying to make sense of DNA analyses renamed the species Aylostera buiningiana but the name is not widely accepted. The authoritative Plant List maintained by Kew uses Rebutia pseudodeminuta. Literature from 1972 and later, including the label for this specimen uses Rebutia buiningiana. Those interested in such matters should Google each of these three names plus the Botany 101-level Wikipedia article for the genus Rebutia. The species, widely available in the cactus trade, comes from Northern Argentina and adjoining Bolivia.

The flowers of this specimen measure 40 mm, the anthers & stamens together are 5 mm, and the spines are 5 mm (each pair of spines are thus 10 mm.)

The plant is located in a private cactus collection in Berkeley, CA.

Rebutia pseudodeminuta—Scarlet Crown Cactus. A cactus with many names; a situation, unfortunately, not uncommon for cactus. The genus Rebutia is considered polyphyletic, but wide differences exist among taxonomists who have studied the genus. A 2011 study trying to make sense of DNA analyses renamed the species Aylostera buiningiana but the name is not widely accepted. The authoritative Plant List maintained by Kew uses Rebutia pseudodeminuta. Literature from 1972 and later, including the label for this specimen uses Rebutia buiningiana. Those interested in such matters should Google each of these three names plus the Botany 101-level Wikipedia article for the genus Rebutia. The species, widely available in the cactus trade, comes from Northern Argentina and adjoining Bolivia.

The flowers of this specimen measure 40 mm, the anthers & stamens together are 5 mm, and the spines are 5 mm (each pair of spines are thus 10 mm.) T

he plant is located in a private cactus collection in Berkeley, CA.

Rebutia pseudodeminuta—Scarlet Crown Cactus. A cactus with many names; a situation, unfortunately, not uncommon for cactus. The genus Rebutia is considered polyphyletic, but wide differences exist among taxonomists who have studied the genus. A 2011 study trying to make sense of DNA analyses renamed the species Aylostera buiningiana but the name is not widely accepted. The authoritative Plant List maintained by Kew uses Rebutia pseudodeminuta. Literature from 1972 and later, including the label for this specimen uses Rebutia buiningiana. Those interested in such matters should Google each of these three names plus the Botany 101-level Wikipedia article for the genus Rebutia. The species, widely available in the cactus trade, comes from Northern Argentina and adjoining Bolivia.

The flowers of this specimen measure 40 mm, the anthers & stamens together are 5 mm, and 0the spines are 5 mm (each pair of spines are thus 10 mm.)

The plant is located in a private cactus collection in Berkeley, CA.

Ceanothus ×vanrensselaeri. A hybrid between C. incanus × C. thyrsiflorus according to the USDA PLANTS database. Taxonomic description is credited to James Roof, first Director of Regional Parks Botanic Garden. Photographed with Olympus Pen E-PL1 with Canon 100 mm FD macro lens. Focus Stacking of 16 images with Zerene Stacker software. Plant is located in Regional Parks Botanic Garden.