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Malacothamnus jonesii var. jonesii

Higher Taxonomy
Family: MalvaceaeView DescriptionDichotomous Key
Habit: Annual to tree; generally with stellate hairs, often with bristles or peltate scales; juice generally mucilage-like; bark fibrous. Leaf: generally cauline, alternate, petioled, simple [palmate-compound], generally palmate-lobed and/or veined, generally toothed, evergreen or not; stipules persistent or not. Inflorescence: head, spike, raceme, or panicle, in panicle or not (a compound panicle), or flowers >= 1 in leaf axils, or flowers generally 1 opposite a leaf or on a spur; bracts leaf-like or not; bractlets 0 or on flowering stalks, often closely subtending calyx, generally in involucel. Flower: generally bisexual, radial; sepals 5, generally fused at base, abutting in bud, larger in fruit or not, nectaries as tufts of glandular hairs at base; petals (0)5, free from each other but generally fused at base to, falling with filament tube, clawed or not; stamens 5--many, filaments fused for most of length into tube around style, staminodes 5, alternate stamens, or generally 0; pistil 1, ovary superior, stalked or generally not, chambers generally >= 5, styles or style branches, stigmas generally 1 or 1--2 × chamber number. Fruit: loculicidal capsule, [berry], or 5--many, disk- or wedge-shaped segments (= mericarps).
Genera In Family: 266 genera, 4025 species: worldwide, especially warm regions; some cultivated (e.g., Abelmoschus okra; Alcea hollyhock; Gossypium cotton; Hibiscus hibiscus). Note: Recently treated to include Bombacaceae, Sterculiaceae, Tiliaceae. Mature fruit needed for identification; "outer edges" are surfaces between sides and back (abaxial surface) of segment. "Flower stalk" used instead of "pedicel," "peduncle," especially where both needed (i.e., when flowers both 1 in leaf axils and otherwise).
eFlora Treatment Author: Steven R. Hill, except as noted
Scientific Editor: Steven R. Hill, Thomas J. Rosatti.
Genus: MalacothamnusView DescriptionDichotomous Key

Habit: Shrubs, sometimes spreading by rhizomes; sparsely to densely stellate-hairy and simple-glandular-hairy, flowers sometimes also with simple or 2-branched nonglandular hairs; stellate hairs stalked or not, 3--40-branched; glandular hairs not branched, often << stellate hairs. Stem: erect to ascending. Leaf: petioled; blades ovate to round (rarely diamond-shaped or +- reniform), unlobed or 3--7-palmate-lobed, margins generally toothed, bases cordate to truncate or wedge-shaped; stipules awl-shaped or linear to lanceolate or sometimes curved; transitioning in inflorescence into bracts +- resembling stipules. Inflorescence: Head-like to spike-like to panicle-like; bracts subtending the often highly reduced inflorescence internodes awl-shaped to linear to triangular to +- round, sometimes curved, occasionally 2--5-lobed, if 2-lobed resembling fused pair of +- modified stipules, smaller bracts sometimes deciduous; bractlets in whorl of 3 subtending calyx, distinct (occasionally fused at base in M. aboriginum), generally awl-shaped to linear, occasionally oblong or narrowly elliptic to ovate, green or partially to all red. Flower: calyx 5-lobed, not enlarging after flowering, not inflated, lobes triangular to ovate, tips acute to acuminate; petals exceeding calyx, unevenly obovate with rounded tip entire to notched or somewhat ragged-margined, pink to occasionally white and often varying in populations, generally drying closed after pollination or in some taxa drying partially to fully open; stamen tube +- included, filaments terminal and subterminal; ovary of 7--14 carpels, ovules 1 per cell, styles 7--14-branched, branches equal in number to carpels, stigmas head-like. Fruit: +- disk-like, fragile when dry, tip minutely stellate-hairy; segments 7--14, drying tan, 1-celled, wide-elliptic to obovoid-reniform, often notched near base, smooth-walled, fully dehiscent with each fruit segment splitting into two separate halves, beak 0. Chromosomes: 2n=34.
Etymology: (Greek: malakos, soft, thamnos, shrub) Note: Measurements for dry specimens; measurements for fresh specimens also provided in key. All Malacothamnus taxa can presumably hybridize; planting Malacothamnus taxa outside their natural range could threaten resident populations, a special concern for rare taxa. Hybridization/intergradation common where geographic ranges of some taxa meet; outside these zones of morphologically intermediate or intergrading plants, identification relatively simple and taxa relatively distinct. Such transition zones mostly between two taxa making parent taxa of intermediates easy to deduce; ranges of 3+ species abut near Santa Clarita making parentage of intermediate plants there unclear. Seeds generally germinate after fires in areas where woody plants burned; plants often short-lived, +- 5 years, but some may persist 20+ years post-burn.
eFlora Treatment Author: Keir Morse
Unabridged Reference: Morse 2023 Malacothamnus Volume 3 -- A Revised Treatment of the Genus Malacothamnus Based on Morphological and Phylogenetic Evidence
Species: Malacothamnus jonesiiView Description 

Habit: <= 3.5 m, spreading by rhizomes. Stem: densely stellate-hairy, surface generally not visible through hairs without magnification, stellate hairs with branches <= 0.8 mm, mostly unstalked, stalks <= 0.3 mm, glandular hairs < 0.1 mm. Leaf: blades +- round, widely ovate or elliptic to diamond-shaped; length generally >= width, unlobed to obscurely 3--5-lobed, bases subcordate to wedge-shaped, pale ashy- to light-green adaxially, paler abaxially, stellate hairs with branches <= 0.6 mm, many stalked, stalks <= 0.2 mm, abaxial stellate hair density 0.5--1.5× adaxial, glandular hairs < 0.1 mm. Inflorescence: spike-like to panicle-like; bracts subtending inflorescence internodes linear to awl-shaped or narrowly triangular, occasionally shallowly to deeply 2+ lobed, 1--5(7.5) mm, 0.5--1.5 mm wide, length 1.5--9× width; bractlets subtending calyx linear to awl-shaped, 2.5--10 mm, 0.2--0.7(1.4) mm wide, length 3--25× width, 0.3--0.9× calyx, green to red. Flower: calyx 5--11.5 mm, lobes 3--8 mm × 2--4 mm, lobe at base 2--3.5 mm wide, widest at base or <= 2 mm above base, length 1.2--3× width, ovate to widely ovate or triangular, tip acute; abaxial calyx stellate hairs with branches 0.1--1.3 mm, mostly unstalked or many stalked, stalks <= 0.7 mm, abaxial glandular hairs < 0.1--0.5 mm; corolla drying closed, petals to +- 2.5 cm.
Note: No evidence of natural hybrids with other species. The three varieties, once treated as species, mostly easily distinguished in flower; morphological intermediates in areas between geographic ranges of the varieties appear almost identical when calyces absent. In general, var. niveus distinguished from other two varieties by longer stellate hair branches, especially on calyx; var. jonesii distinguished from var. gracilis by spike-like rather than generally panicle-like inflorescence. Intermediates between var. jonesii and var. niveus found near Atascadero (SCoR); intermediates between var. gracilis and var. niveus found along southern border of San Luis Obispo Co. between more typical populations of each variety. Malacothamnus abbottii can be confused with M. jonesii when flowers absent (leaves very similar); M. abbottii generally has much wider bractlets subtending calyx than M. jonesii, flowers much later than var. jonesii, and has much shorter stellate hair branches on calyx than var. niveus. Native range of M. abbottii adjacent to north and west range of M. jonesii, but introduced into range of var. niveus near southern border of San Luis Obispo Co.
Malacothamnus jonesii (Munz) Kearney var. jonesii
Habit: <= 3 m. Stem: stellate hairs with branches <= 0.4 mm (mean per plant 0.1--0.3 mm), stalks <= 0.2 mm. Leaf: blades +- round or widely ovate or diamond-shaped, unlobed to obscurely 3-lobed, bases truncate to wedge-shaped (rarely subcordate), stellate hairs with branches <= 0.5 mm (mean 0.2 mm), stalks <= 0.2 mm, abaxial stellate hair density 1--1.5× adaxial. Inflorescence: spike-like (rarely very narrowly panicle-like); bracts subtending inflorescence internodes 1.5--4.5 mm, 0.5--1.5 mm wide, length 2--9× width; bractlets subtending calyx linear to awl-shaped, 3--5.5 mm, 0.2--0.7 mm wide, length 5--25x width, 0.4--0.7× calyx, green to red. Flower: calyx 5--8 mm, lobes 3--5 mm × 2--3 mm, lobe at base 2--3 mm wide, widest at base or <= 1 mm above base, length 1.2--2× width, abaxial calyx stellate hairs with branches 0.1--0.9 mm (mean per plant 0.2--0.4 mm), mostly unstalked, stalks <= 0.3 mm, abaxial glandular hairs < 0.1--0.3 mm (mean per plant < 0.1--0.1 mm); petals to +- 2.5 cm.
Ecology: Early-recovering post-burn woody vegetation, edges of openings, some plants occasionally persisting into more mature vegetation stages; Elevation: 175--510 m. Bioregional Distribution: SCoR (San Luis Obispo, s Monterey cos.). Flowering Time: (Mar)Apr--May Note: Intergrades with var. niveus.
Synonyms: Malvastrum jonesii Munz; Malvastrum dudleyi Eastw.
Jepson eFlora Author: Keir Morse
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Listed on CNPS Rare Plant Inventory

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Botanical illustration including Malacothamnus jonesii var. jonesii

botanical illustration including Malacothamnus jonesii var. jonesii

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Citation for this treatment: Keir Morse 2023, Malacothamnus jonesii var. jonesii, in Jepson Flora Project (eds.) Jepson eFlora, Revision 12,, accessed on June 15, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on June 15, 2024.

Malacothamnus jonesii  
var. jonesii
click for enlargement
©2017 Keir Morse
Malacothamnus jonesii  
var. jonesii
click for enlargement
©2017 Keir Morse
Malacothamnus jonesii  
var. jonesii
click for enlargement
©2017 Keir Morse
Malacothamnus jonesii  
var. jonesii
click for enlargement
©2017 Keir Morse
Malacothamnus jonesii  
var. jonesii
click for enlargement
©2017 Keir Morse

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Geographic subdivisions for Malacothamnus jonesii var. jonesii:
SCoR (San Luis Obispo, s Monterey cos.).
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


Data provided by the participants of the  Consortium of California Herbaria.
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Blue line denotes eFlora flowering time (fruiting time in some monocot genera).