View source for Malacothrix

{{Treatment/ID
|accepted_name=Malacothrix
|accepted_authority=de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
|publications={{Treatment/Publication
|title=in A. P. de Candolle and A. L. P. P. de Candolle, Prodr.
|place=7: 192. 1838
|year=1838
}}
|common_names=Desertdandelion
|basionyms=
|synonyms=
|hierarchy=Asteraceae;Asteraceae tribe Cichorieae;Malacothrix
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Cichorieae]]</div><div class="higher-taxon"><small>genus</small>[[Malacothrix]]</div></div>
|etymology=Greek malakos, soft, and thrix, hair
|volume=Volume 19
|mention_page=page 219, 309, 349, 360
|treatment_page=page 310
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Annuals </b>or perennials, 2–70(–200) cm; taprooted (rhizomatous or taproots becoming caudices in M. saxatilis). <b>Stems</b> 1–15 (usually from basal rosettes), usually erect, sometimes ± prostrate, usually branched (scapiform in M. californica), usually glabrous (sometimes piloso-hirsute, stipitate-glandular, or tomentose to arachnose or puberulent, at least proximally or in leaf axils). <b>Leaves</b> usually basal and cauline; sessile; blades mostly oblong or lanceolate to obovate, oblanceolate, or spatulate (often pinnately lobed), ultimate margins entire or ± dentate (faces usually glabrous, sometimes piloso-hirsute or tomentose to arachnose or puberulent). <b>Heads</b> usually in corymbiform to paniculiform arrays (borne singly in M. californica). <b>Peduncles</b> not inflated distally, usually bracteate. <b>Calyculi</b> 0 (outer phyllaries intergrading with inner) or of 3–30+, ± deltate or lanceolate to linear or subulate, subequal to unequal bractlets (in 1–2 series distinct from phyllaries, margins usually hyaline, faces usually glabrous, sometimes arachnose, rarely stipitate-glandular). <b>Involucres</b> usually broadly to narrowly campanulate, sometimes hemispheric, (5–22+ ×) 2–22+ mm diam. <b>Phyllaries</b> either (without calyculi) 25–80+ in 4–6+ series and orbiculate to oblong, lance-oblong, lanceolate, or linear, unequal, or (with calyculi) 12–25+ in 2–3 series and oblong or lanceolate to linear, subequal; margins ± hyaline, 0.05–2.5 mm, apices obtuse to acute or acuminate. <b>Receptacles</b> flat to ± convex, pitted or smooth, sometimes bristly, epaleate. <b>Florets</b> 15–270; corollas yellow or white (sometimes reddish or lavender abaxially; outer ligules exserted 1–15 mm). <b>Cypselae</b> (monomorphic) stramineous to brown or purplish brown, ± prismatic or cylindro-fusiform, not beaked, ribs 15 (often 5 more prominent than others, apices of ribs sometimes projecting and forming coronas subtending pappi), usually glabrous (sometimes minutely hirtellous or muriculate); pappi 0, or (single or double) persistent, whitish, crenate crowns or rings of (1–)8–25+ teeth (mostly 0.05–0.1 mm) plus 0–6, coarse, smooth bristles (setiform scales), all in ± 1 series, subtending (i.e., exterior to) the readily falling, inner (or single and only) pappi of 15–35, basally coherent, white, fine, smooth to barbellulate or (proximally) ± plumose bristles in 1 series (falling all together or in groups). <b>x</b> = 7, 9.</span><!--

-->{{Treatment/Body
|distribution=w United States;nw Mexico;introduced in South America.
|discussion=<p>Species 20 (18 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=davis1997a
|text=Davis, W. S. 1997. The systematics of annual species of Malacothrix (Asteraceae: Lactuceae) endemic to the California Islands. Madroño 44: 223–244.
}}{{Treatment/Reference
|id=williams1957a
|text=Williams, E. W. 1957. The genus Malacothrix (Compositae). Amer. Midl. Naturalist 58: 494–512.
}}
}}<!--

--><div class="treatment-key">
==Key==
<div class="treatment-key-group">
  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Perennials (sometimes flowering first year)
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Annuals
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Corollas medium yellow; persistent pappi 0
|[[Malacothrix incana|Malacothrix incana]]
|-id=key-0-2
|2
|Corollas white (usually each with abaxial purple stripe); persistent pappi of fimbriate crowns or 20–25, blunt teeth (0.01–0.05 mm) plus 0 bristles
|[[Malacothrix saxatilis|Malacothrix saxatilis]]
|-id=key-0-3
|3
|Involucres hemispheric; phyllaries orbiculate (outer) to oblong or linear, hyaline margins 1–2.5 mm wide
|[[Malacothrix coulteri|Malacothrix coulteri]]
|-id=key-0-3
|3
|Involucres usually ± campanulate (to hemispheric in M. sonchoides); bractlets of calyculi and/or phyllaries ovate to lanceolate, linear, or subulate, hyaline margins 0.05–0.3(–1) mm wide
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Stems seldom branched (heads usually borne singly on scapiform peduncles); cypsela ribs: 5 more prominent than others
|[[Malacothrix californica|Malacothrix californica]]
|-id=key-0-4
|4
|Stems branched (heads usually in corymbiform to paniculiform arrays); cypsela ribs ± equal, or 5 more prominent than others
|[[#key-0-5| > 5]]
|-id=key-0-5
|5
|Cauline leaves not or seldom notably reduced distally (Channel Islands, California)
|[[#key-0-6| > 6]]
|-id=key-0-5
|5
|Cauline leaves usually reduced distally (M. clevelandii and M. similis are known from Channel Islands, California)
|[[#key-0-9| > 9]]
|-id=key-0-6
|6
|Persistent pappi usually 0, rarely of 1–2 bristles; pollen 70–100% 3-porate
|[[#key-0-7| > 7]]
|-id=key-0-6
|6
|Persistent pappi of 15–20 teeth (0.01–0.1 mm) plus 1–2 bristles; pollen 70–100% 4-porate
|[[#key-0-8| > 8]]
|-id=key-0-7
|7
|Stems erect or ± prostrate (forming mats); proximal cauline leaves usually fleshy (lobes nearly equal, apices obtuse); San Miguel, Santa Cruz, and Santa Rosa islands
|[[Malacothrix indecora|Malacothrix indecora]]
|-id=key-0-7
|7
|Stems erect (not forming mats); proximal cauline leaves usually not fleshy (lobes usually unequal, apices acute or obtuse); Anacapa, San Clemente, San Nicolas, and Santa Barbara islands
|[[Malacothrix foliosa|Malacothrix foliosa]]
|-id=key-0-8
|8
|Calyculi 0; phyllaries 31–49 in 5–6+ series, hyaline margins 0.6–1 mm wide; Anacapa and Santa Cruz islands, California
|[[Malacothrix squalida|Malacothrix squalida]]
|-id=key-0-8
|8
|Calyculi of 7–11 bractlets; phyllaries 9–13 in 2–3 series, hyaline margins 0.1–0.2 mm wide; Anacapa Island, California
|[[Malacothrix junakii|Malacothrix junakii]]
|-id=key-0-9
|9
|Corollas 4–10 mm; outer ligules exserted 1–4 mm
|[[#key-0-10| > 10]]
|-id=key-0-9
|9
|Corollas (7–)10–23+ mm; outer ligules exserted 5–15+ mm
|[[#key-0-14| > 14]]
|-id=key-0-10
|10
|Proximal cauline leaves (pinnately lobed, lobes 3–5 pairs, ± equal, bases white-hairy) ± fleshy; persistent pappi of crenate crowns plus 0 bristles; pollen 70–100% 3-porate.
|[[Malacothrix phaeocarpa|Malacothrix phaeocarpa]]
|-id=key-0-10
|10
|Proximal cauline leaves (pinnately lobed or not) not fleshy; persistent pappi of 8–24+ teeth plus 1–2 bristles; pollen 3- or 4-porate
|[[#key-0-11| > 11]]
|-id=key-0-11
|11
|Proximal cauline leaves oblanceolate to lance-linear; corollas pale yellow; cypselae ± cylindro-fusiform or prismatic, 1.2–1.8 mm (ribs extending to apices, 5 more prominent than others); persistent pappi of 14–24+ needlelike teeth plus 1 bristle (mainly California)
|[[#key-0-12| > 12]]
|-id=key-0-11
|11
|Proximal cauline leaves obovate to narrowly oblanceolate; corollas white or pale yellow; cypselae ± cylindro-fusiform, 1.7–2.3 mm (ribs not extending to apices, ± equal); persistent pappi of 8–18 teeth plus 1–2 bristles (Arizona, California, Nevada)
|[[#key-0-13| > 13]]
|-id=key-0-12
|12
|Stems branched mostly distally, glabrous; cauline leaves: margins usually dentate; cypselae (stramineous to brown) 1.2–1.8 mm; pollen 3-porate (mean diam. 25 µm)
|[[Malacothrix clevelandii|Malacothrix clevelandii]]
|-id=key-0-12
|12
|Stems branched mostly proximally; cauline leaves: margins usually entire; cypselae 1.4–1.7 mm (purplish brown); pollen 4-porate (mean pollen diam. 30 µm)
|[[Malacothrix similis|Malacothrix similis]]
|-id=key-0-13
|13
|Corollas white or pale yellow; cypselae 1.7–2 mm (bases slightly expanded, distal 0.3 mm smooth); pollen 70–100% 3-porate
|[[Malacothrix sonorae|Malacothrix sonorae]]
|-id=key-0-13
|13
|Corollas usually yellow, sometimes white; cypselae 1.7–2.3 mm (bases not expanded, distal 0.1–0.2 mm smooth); pollen 70–100% 4-porate
|[[Malacothrix stebbinsii|Malacothrix stebbinsii]]
|-id=key-0-14
|14
|Proximal cauline leaves pinnately lobed (lobes 2–6+ pairs, filiform or triangular to oblong, subequal to unequal, apices acute), not fleshy, ultimate margins dentate or entire; cypsela ribs ± equal
|[[#key-0-15| > 15]]
|-id=key-0-14
|14
|Proximal cauline leaves pinnately lobed (lobes 3–8 pairs, ± oblong to triangular, ± equal, apices obtuse or acute), ± fleshy, ultimate margins usually dentate; cypsela ribs ± equal or 5 more prominent than others
|[[#key-0-16| > 16]]
|-id=key-0-15
|15
|Proximal cauline leaves usually pinnately lobed (lobes filiform); receptacles bristly; cypselae ± cylindro-fusiform (sometimes weakly 5-angled, ribs extending to apices).
|[[Malacothrix glabrata|Malacothrix glabrata]]
|-id=key-0-15
|15
|Proximal cauline leaves sometimes pinnately lobed (lobes relatively broad, triangular to deltate); receptacles not bristly; cypselae ± cylindro-fusiform (ribs not extending to apices, distal 0.3 mm of cypselae smooth)
|[[Malacothrix fendleri|Malacothrix fendleri]]
|-id=key-0-16
|16
|Corollas white or yellow (usually with lavender abaxially); cypselae 1.2–2 mm; persistent pappi 0
|[[Malacothrix floccifera|Malacothrix floccifera]]
|-id=key-0-16
|16
|Corollas lemon or medium yellow; cypselae 1.8–4 mm; persistent pappi of 12–25+ irregular, blunt teeth plus 0–6 bristles
|[[#key-0-17| > 17]]
|-id=key-0-17
|17
|Distal cauline leaves narrowly triangular to linear (bases usually ± dilated, ± clasping); persistent pappi of crenate crowns or 12–25+ teeth plus 0 bristles.
|[[Malacothrix sonchoides|Malacothrix sonchoides]]
|-id=key-0-17
|17
|Distal cauline leaves ± elliptic to linear (bases narrowly cuneate); persistent pappi of 12–15 teeth plus 0–6 bristles
|[[Malacothrix torreyi|Malacothrix torreyi]]
|}
</div></div><!--

-->{{#Taxon:
name=Malacothrix
|author=W. S. Davis
|authority=de Candolle in A. P. de Candolle and A. L. P. P. de Candolle
|rank=genus
|parent rank=tribe
|synonyms=
|basionyms=
|family=Asteraceae
|illustrator=Yevonn Wilson-Ramsey
|distribution=w United States;nw Mexico;introduced in South America.
|reference=davis1997a;williams1957a
|publication title=in A. P. de Candolle and A. L. P. P. de Candolle, Prodr.
|publication year=1838
|special status=
|source xml=https://jpend@bitbucket.org/aafc-mbb/fna-data-curation.git/src/9216fc802291cd3df363fd52122300479582ede7/coarse_grained_fna_xml/V19-20-21/V19_463.xml
|tribe=Asteraceae tribe Cichorieae
|genus=Malacothrix
}}<!--

-->[[Category:Treatment]][[Category:Asteraceae tribe Cichorieae]]