44 Rhodora [Marcu 
collectors are inclined to ignore them, and from this it follows that 
little material finds its way into the public herbaria. We are there- 
fore unable to state full ranges for any of the species; but by the cita- 
tion of characteristic specimens examined it is hoped that the following 
synopsis may be made more readily intelligible. 
A. Heads corymbose, long-peduncled: leaf-blades round-ovate, obtuse; 
petioles strongly angular, deeply furrowed. 
Petioles solid: heads very large and broad, 3-4.5 em. in diameter; in- 
volucre glabrous, green (rarely purple): outermost bracts about 1 cm. 
long; the middle and inner slightly longer, subequal and exceeding the 
corollas; the innermost with pale firm slender gradually attenuate tips: 
broad upper portion of corolla shorter than the slender tube: achenes 
6-7 mm. long, fawn-color, often dark-mottled, slightly rugose below 
the crenate-bordered summit. . . ZUM ee A. CA 
Petioles hollow: heads smaller, 2-2.7 em. — por ee more or less 
arachnoid: outermost bracts 4-7 mm. long; the middle and inner 
successively longer, all or all but the inner conspicuously shorter than 
the corollas; the innermost with membranous more or less colored blunt 
or cuspidate tips: broad upper portion of the corolla as long as the 
tube: achenes 4.5-7 mm. long, gray, usually dark-mottled, rugulose 
from base to the entire summit... . . . . . 2. A. tomentosum. 
B. Heads racemose or subracemose, rarely long-peduncled: leaf-blades 
ovate-oblong, usually less obtuse; petioles slightly angular. 
Petioles hollow: heads medium, 2.5-3.5 em. broad: involuere gla- 
brous or arachnoid, green or purplish: outermost bracts short, 5-7 mm. 
long; the middle and inner successively much longer, equaling or ex- 
ceeding the corollas; the innermost long-attenuate, firm and aristate: 
upper and lower portions of the corolla equal in length: achenes 5.5- 
7.5 mm. long, dark-brown, sometimes light-mottled, not rugulose, the 
summit önti 2... s. v o or oS uw m rn 
Petioles hollow: heads small, 1.5-2.5 em. broad: involuere glabrous 
or arachnoid, green or purplish: the outer bracts short; the middle and 
inner successively much longer, all conspicuously shorter than the corol- 
las; the innermost attenuate, firm and aristate: upper and lower 
portions of the corolla equal in length: achenes 5-6 mm. long, gray or 
ashy-brown, usually ee smooth or faintly rugulose, the 
summit entire. d vcra V NT quo. I m HW. UMS 
1. A. Lappa L. Sp. Pl. 816 (1753). Arctium majus Bernh. 
Syst. Verz. Erfurt. 154 (1800). Lappa officinalis All. Fl. Ped. i. 145 
(1785). Lappa major Gaertn. Fruct. ii. 379 (1791). Arctium 
Lappa, var. majus Gray, Syn. Fl. i. pt. 2, 397 (1878).— Typical speci- 
mens examined. New Brunswick: dry roadside, Four Falls, Aug- 
1 These measurements of the heads include the spreading tips of the bracts. 
