Home Flora of Missouri
Home
Name Search
Families
Volumes
Helianthus grosseserratus M. Martens Search in The Plant ListSearch in IPNISearch in Australian Plant Name IndexSearch in NYBG Virtual HerbariumSearch in Muséum national d'Histoire naturelleSearch in Type Specimen Register of the U.S. National HerbariumSearch in Virtual Herbaria AustriaSearch in JSTOR Plant ScienceSearch in SEINetSearch in African Plants Database at Geneva Botanical GardenAfrican Plants, Senckenberg Photo GallerySearch in Flora do Brasil 2020Search in Reflora - Virtual HerbariumSearch in Living Collections Decrease font Increase font Restore font
 

Published In: Index Seminum [Louvain] [4]. 1839. (Index Seminum (Louvain)) Name publication detailprotologue
 

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

Export To PDF Export To Word

5. Helianthus grosseserratus M. Martens (sawtooth sunflower)

H. grosseserratus ssp. maximus R.W. Long

Pl. 280 e, f; Map 1192

Plants perennial herbs, with short-creeping or sometimes longer, thick, branched rhizomes, sometimes occurring as dense colonies of stems. Stems often appearing somewhat clumped, 50–300 cm long, glabrous below the midpoint, often sparsely to moderately pubescent with short, ascending hairs toward the tip, often somewhat glaucous. Leaves relatively numerous and well developed along the stem (usually with 20–25 nodes), mostly alternate or occasionally most of the leaves opposite and only the uppermost ones alternate, all or nearly all short-petiolate. Blades of the stem leaves 5–30 cm long, 1–9 cm wide, narrowly lanceolate to narrowly ovate (mostly 5–10 times as long as wide), flat or only shallowly concave, not folded longitudinally, tapered at the base, tapered to a sharply pointed tip, the margins finely to coarsely and sharply toothed (rarely entire), flat, the upper surface sparsely to moderately pubescent with minute, broad-based hairs, usually not or only slightly roughened to the touch, the undersurface densely pubescent with minute, soft, appressed hairs, both surfaces also with sparse to moderate, sessile, yellow glands, more or less with 1 main vein but the lowermost pair of lateral veins usually slightly more prominent than the other pinnate lateral veins. Inflorescences of solitary terminal heads or more commonly appearing as open clusters or open panicles. Involucre 10–15 mm long, 15–25 mm in diameter, mostly extending slightly beyond the tips of the disc corollas, the bracts in 2 or 3 subequal series, narrowly lanceolate to nearly linear, tapered to a sharply pointed, slender, loosely ascending to more commonly spreading or recurved tip, the margins with short, ascending to occasionally spreading hairs, at least toward the base, the outer surface glabrous or sparsely hairy toward the base but usually lacking glands. Receptacle convex, the chaffy bracts 7–9 mm long, narrowly oblong-triangular to nearly linear, angled or short-tapered to a sharply pointed, green, minutely hairy tip, the outer surface also minutely hairy. Ray florets 10–25, the corolla 2.0–4.5 cm long, glabrous. Disc florets with the corolla 5–6 mm long, yellow throughout. Pappus of 2 scales 2.0–2.5 mm long, these narrowly triangular, tapered abruptly to a sharply pointed, often minutely awnlike tip. Fruits 3–4 mm long, narrowly wedge-shaped, flattened but more or less 4-angled in cross-section, the surface glabrous, often finely mottled with dark brown to nearly black and lighter brown patches. 2n=34. July–October.

Scattered in the Glaciated and Unglaciated Plains Divisions and the western portion of the Ozark and Ozark Border Divisions; absent from most of the southeastern quarter of the state (eastern U.S. west to North Dakota and Texas; Canada; introduced sporadically in the northwestern U.S.). Bottomland and upland prairies; bases of bluffs, banks of streams and rivers, fens, and margins of ponds and lakes; also ditches, margins of cultivated fields, pastures, railroads, roadsides, and open, disturbed areas.

Rarely collected plants with most of the disc florets converted to rays have been called f. pleniflorus Wadmond. It is not clear whether this represents some form of genetic mutation or a symptom of a disease. Steyermark (1963) noted that hybrids have been recorded between H. grosseserratus and H. maximilianii (H. ×intermedius R.W. Long) in adjacent states and should be searched for in Missouri. Thus far a single collection made by B. F. Bush in 1916 in Jackson County (and labeled as introduced there) appears to represent this hybrid.

 


 

 
 
© 2024 Missouri Botanical Garden - 4344 Shaw Boulevard - Saint Louis, Missouri 63110