CARDUACEAE 1231 
or purplish ligules. Disk-flowers several, perfect, the corollas usually with 4lobes. An- 
thers obtuse at the base. Stigmas flattened, with short appendages. Achenes flattened, 
often pubescent. Pappus of many brittle hair-like bristles in one series. 
Inner bracts of the involucre copiously pubescent. 1. L. linifolium. 
Inner bracts of the involcure glabrous or nearly so. 
Stems diffusely branched at the base: ray-flowers with purplish ligules. 2. L. divaricatum, 
Stem usually simple below the inflorescence: ray-flowers with white ligules. 
Stem-leaves with mainly entire or merely few-toothed blades. 8. L. Canadense. 
Stem-leaves with mainly pinnatifid or pinnatifid-toothed blades. 4. L. Bonariense. 
1. Leptilon linifdlium (Willd.) Small. Stems 2-7 dm. tall, hirsute, racemose or 
paniculate above. Leaf-blades narrowly spatulate to linear, 1.5-10 cm. long, the lower 
ones. incised or laciniate, slender-petioled, the upper entire or sparingly toothed : involucres 
2-3 mm. high ; bracts linear to linear-subulate. 
In waste places, South Carolina to Florida and Alabama. Spring to fall. 
2. Leptilon divaricatum (Michx.) Raf. Stems diffusely much branched, 1-3 dm. 
tall, finely hirsute and somewhat cinereous. Leaf-blades narrowly linear to subulate, 1-4.5 
cm. long, entire: involucres 1.5-2 mm. high; bracts narrowly linear to linear-subulate 
ray-flowers with purplish ligules which rarely surpass the style-branches. 
In dry soil, Minnesota to Illinois, Alabama, Nebraska and Texas. Summer and fall. 
3. Leptilon Canadénse (L.) Britton. Stems glabrate or sparsely hirsute, 3-20 dm. 
tall, or sometimes diminutive, simple to the paniculate inflorescence : leaf-blades linear or 
nearly so, or spatulate near the base of the stem, entire or coarsely few-toothed, conspicu- 
ously ciliate near the base: heads normally very numerous: involucres 3-3.5 mm. high ; 
bracts in 1 series, linear-subulate to linear, the outer ones often pubescent: corollas of the 
disk-flowers usually 4-lobed : ray-flowers with white or whitish little-exserted ligules. 
In various situations, nearly throughout North America, Also widely distributed in Europe and 
South America. Spring to fall. 
4. Leptilon Bonariénse (L.) Small. Similar to L. Canadense in habit : leaf-blades 
finely pubescent, mainly pinnatifid or pinnatifid-toothed, but those of the branches or near 
the inflorescence entire or nearly so: involucres 3-4 mm. high ; bracts in 3 series : corollas 
of the disk-flowers usually 5-lobed ; ligules of the ray-flowers scarcely, if at all, exserted. 
In waste ground, Pensacola, Florida. Introduced from tropical and South America. 
55. DOELLINGERIA Nees. 
Perennial caulescent herbs. Leaves alternate: blades firm, entire, ciliate, sessile. 
Heads in corymbose cymes, several or many. Involucres campanulate to hemispheric, 
several- to many-flowered : bracts imbricated in 2-4 series, narrow, appressed, neither 
herbaceous nor foliaceous at the tip. Receptacle pitted. Ray-flowers few or several, pis- 
tillate : ligules white or nearly so. Disk-flowers perfect : corollas narrow, expanded into a 
5-lobed throat. Anthers obtuse at the base. Stigma-appendages typically ovate or sub- 
ulate. Achene nearly terete or flattened, sometimes nerved, slightly broadened upward. 
Pappus double, the outer series of short bristles or scales, the inner of capillary bristles, 
all or some of them thickened at the tip. 
Ray-flowers with linear ligules over 10 mm, long: inner bracts of the involucre acuminate. 
D. reticulata. 
Ray-flowers with oblong ligules less than 10 mm. long: inner bracts of the invo- 
lucre merely acute or obtuse. k 
Achenes nearly terete, ribless, less than 1 mm. wide. 2 i 
Ovary and achene pubescent : outer involucral bracts ciliate near the tip. 
1nvolucral bracts acute or acutish, the inner linear, ciliate at the tip. 2. D. umbellata. 
Involucral bracts obtuse, the inner oblong, eciliate. 3. D. humilis. — 
Ovary and achene glabrous : outer involucral bracts ciliate all around. 4, D. sericocarpoides. 
Achenes much flattened, ribbed, over 1 mm. wide. 5. D. infirma. 
1. Doellingeria reticulata (Pursh) Greene. Stems 3-12 dm. tall, finely soft-pubes- 
cent, fastigiate-corymbose above : leaves rather numerous ; blades oblong or oval, varying 
to oblong-obovate or narrowly oblong, 4-8 cm. long, or shorter on the upper part of the 
stem, obtuse or merely acutish, entire or essentially so, sometimes undulate, prominently 
fine-reticulate beneath, manifestly reticulate above: heads few or numerous, slender-pe- 
duncled : involucres about. 6 mm. high; bracts linear to narrowly linear-lanceolate, acute 
or acuminate, the tips erect : ray-flowers 9-13 ; ligules 11-15 mm. long: achenes 4 mm. 
long, pubescent. 
In low pine lands, South Carolina to Florida. Spring and summer. 
2. Doellingeria umbellàta ( Mill.) Nees. Stems 6-25 dm. tall, glabrous or somewhat 
pubescent above, corymbosely branched : leaves numerous ; blades membranous, narrowly 
