Subtribe 6. A nthemideje. Heads mostly heterogamous. Pappus none or coroni-
form, rarely squamellate. Anthers not caudate. Branches of the style truncate
and bearded at the apex, rarely terminated by a short cone. Leaves mostly
alternate.
Subtribe 7. Gnaphalieie. Heads homogamous and discoid, or rarely heterogamous.
Anthers caudate. Pappus of capillary or setaceous bristles, very
rarely none. Leaves mostly alternate.
Subtribe 8. S enscionea:. Heads homogamous or heterogamous, discoid, or radiate.
Anthers not caudate. Pappus of capillary bristles, or very rarely
wanting in the exterior flowers. Leaves alternate.
Subtribe 1. M elampodineaj, DC. (Polygamia Necessaria, Linn.)—
Flowers all unisexual; the pistillate and staminate flowers either in different
individuals, or in different heads of the same plant, or in the same head.
Anthers not caudate at the base. Receptacle almost always chaffy. P a p pus
none, or somewhat coroniform, or awned, never of bristles.
CONSPECTUS OF THE GENERA.
Div. 1. Melampodie®.—Heads monoecious, radiate. Achenia corticate.
€9. Melampodium. Inner scales of the involucre investing the achenia.
Div. 2. Millerieal—Heads monoecious, radiate. Achenia not corticate nor winged.
70. Blennosperma. Receptacle naked. Achenia pulverulent-papillose.
71. Polymnia. Receptacle chaffy. Achenia obovoid: pappus none.
72. Chrysogonom. Receptacle chaffy. Achenia obcompressed 4-angular: pappus
coroniform-toothed.
Div. 3. Silphiea;.—Heads monoecious, radiate; the rays deciduous. Achenia not
corticate, obcompressed, or winged. Pappus of two teeth or short awns.
73. Silphium. Achenia winged, in more than one series.
74. Berlandiera. Achenia wingless, one adhering to each inner involucral scale.
75. Engelmannia. Achenia wingless, free: pappus 2-auriculate-squamellate.
Div. 4. P artheniea;.—Heads monoecious, radiate: rays marcescent. Achenia not
corticate, obcompressed.
76. P arthenium. Achenia 5; their callous margins united at the base with the
chaff of 2 contiguous sterile flowers.
Div. 5. Ivea:.—Heads monoecious, not radiate. Anthers scarcely united.
77. Cyclachjena. Heads glomerate-paniculate, bracteate: the central flowers
abortive.
78. Iva. Heads bracteate. Receptacle chaffy. Flowers glabrous.
79. P icrothamnus. Receptacle naked. Achenia and corolla woolly.
Div. 6. Ambrosie®.—Heads heterocephalous; the sterile and fertile heads in the
same or different plants, not radiate. Anthers distinct.
80. A mbrosia. Fertile involucre 1-celled, 1-flowered, not spinose throughout.
81. Franseria. Fertile involucre 1-4-celled, spinose; the sterile 8-12-toothed.
82. Xanthibm. Fertile involucre 2-celled; the scales of the sterile distinct.
Div. 1 . M e r a m p o d i e .®, DC.—Fertile and sterile flowers in the
same heads; the former several, ligulate; the latter central, tubular. Achenia
corticate* (that is, invested and concrete with the scales of the involucre
or chaff of the receptacle). Pappus none. Anthers united.
69. MELAMPODIUM. Linn.; Geertn.fr. t. 169; R. Br. in Linn,
irans. 12. p. 104.
Heads many-flowered ; the ray-flowers 5-10, in a single series ; those of
the disk sterile by the abortion of the style. Involucre double ; the extenor
of 3-5 flat and spreading foliaceous scales; the inner as many as the ray-
flowers and enclosing their achenia. Receptacle convex or subulate-conical,
chaffy; the chaff membranaceous, deciduous. Style in the sterile-flowers
undivided and hairy above. Achenia of the disk abortive ; of the ray obovoid,
smooth, slightly curved, invested by the inner scales of the involucre,
which are often rugose or tuberculate, or cucullate at the summit, and either
truncate or produced into 1-3 teeth or awns.—Herbaceous or suffruticose
(chiefly Mexican)' plants, with dichotomous stems, opposite sessile leaves,
and terminal or alar peduncles bearing a single head. Flowers yellow, or
the rays rarely (in two species ?) white.
1. M. ramosissimum (DC.) I stem slightly suffruticose, much branched,
glabrous ; leaves linear, pubescent with somewhat appressed hairs, entire, or
remotely dentate-lobed or sinuate ; peduncles longer than the leaves; rays
oblong-linear, small (yellow); exterior scales of the involucre oval pubescent
externally; the interior involving the achenia, tuberculate at the base,
the summit expanded into a broad hood, with a dorsal uncmate acummation.
DC.! prodr. 5. p. 518.
Texas, Berlandier ! (v. sp. in herb. DC.)
2. M. leucanthum: suffruticose, much branched at the base, strigose
throughout and dotted with minute resinous globules; leaves very numerous,
linear the lower linear-spatulate, obtuse, entire, stngose-hispid above; peduncles
much longer than the leaves; rays oval-oblong, emargmate, thrice
the length of the ovate and hairy exterior scales of the involucre ; the inner
enclosing the achenia, tuberculate-scabrous towards the base, dilated above
into a short smooth hood, truncate at the summit, with the margin entire and
lfl Texas, Dr. Riddell /—Plant 6-10 inches high. Leaves 1-2 inches long,
somewhat canescent, above with hispid, beneath with weak hairs. Rays
about half an inch long. Chaff of the receptacle lacimate-fimbriate at the
summit.—Nearly allied to (and possibly not distinct from) M. cmereum,
jDC», a Mexican species collected by Berlandier, which is also remarkable
for having white rays.
Div. 2. M i i i i r i e j s , DC.—Fertile and sterile flowers in the same
heads ; the former few, ligulate, or sometimes tubular and 3-cleft; the latter
central, tubular. Achenia not corticate, (that is not coherent with the scales
* We have used the term as employed and defined by De Candolle in this place.
But in the Heliopsideae, and other places, this author also terpis those achenia corticate
in which the exterior covering (calyx-tube) is separable from the interior.