304 COMPOSITE. Tetragonotheca. 



pandly and unequally toothed, or with coarse and sharp salient teeth. Invo- 

 lucre, when expanded, two inches or more in diameter. Corolla of the disk 

 with the proper tube short (the stamens inserted near the base), somewhat 

 coriaceous, hairy externally (as also the summit of the ovary) ; the throat 

 nearly cylindrical; tlie teeth ovate-lanceolate. — There are more commonly 

 10 nerves in the disk-corolla, apjiroximate in pairs and nearly correspondent 

 to the sinuses, near which the}' diverire, one traversing each lacinia as near 

 to the axis as to the margin, and uniting within the apex with its fellow of 

 the adjacent sinus, in the ordinary manner. Very frequently there are 3 

 nerves to each set, the middle one exactly corresponding to the sinus, but 

 often vanishing or confluent with one of the lateral, in some part of its course : 

 there are no nerves corresponding with the axis of the lacinia3 as in Helian- 

 thus. The rays present 10 nerves, or by bifurcation 12 to 14. 



89. HALEA. 



Heads many-flowered; the ray-flowers (10-12) pistillate; those of the 

 disk tubular, perfect. Involucre double ; the exterior of 4 or 5 ovate folia- 

 ceous scales, united below the middle, valvate in aestivation, at length shorter 

 than the disk ; the interior of numerous (about 15) obovate or oval-lanceolate 

 acuminate erect chaffy scales, more or less imbricated, nearly flat, many- 

 nerved, similar to the chaff of the large conical receptacle. Corolla glabrous 

 or nearly so ; the rays broadly oval, slightly 3-toothed, tapering and involute 

 at the base, but not tubular ; of the disk deeply 5-toothed, 10-nerved. Style 

 as in Tetragonotheca. Achenia 4-sided, pubescent, with a broad and flat 

 summit, crowned with a short pappus, composed of about 20 thick and oval 

 distinct and entire scales. — A tall and stout branching perennial herb, some- 

 what pubescent when young, with much the aspect and fohage of Tetra- 

 gonotheca. Stem striate, quadrangular below. Leaves opposite, or rarely 

 ternately verlicillate, rather large, veiny, the margin thickly set with sharp 

 unequal salient or laciniate teeth, all sessile ; the lowermost oval-oblong, 

 tapering into a narrowed base, more or less connate ; the upper ovate or 

 ovate-oblong, connate-perfoliate. Heads (rather large) on naked peduncles 

 terminating the stem or branches. Flowers yellow. 



H. Ludoviciana. 



Dry sandy soil, Western Louisiana, Dr. Leavemvorth ! Dr. Hale! Texas, 

 Drummojid .' Dr. LeavcnworlJt .' June-Aiig. — Stem 2-4 feet high. Heads 

 about an inch in diameter. Exterior involucre very slightly angled at the 

 junction of the scales; wliich are broadly ovate, obtuse, or scarcely acumi- 

 nate, glabrous, persistent, and at length shorter than the elongated conic re- 

 ceptacle. Rays not twice the length of the involucre, ]0-nerved. Corolla 

 of the disk with a very short coriaceous proper tube (as in Tetragonotheca), 

 the elongated throat slightly dilated : the 10 nerves in pairs corresponding 

 with the sinuses, approximate but distinct from the base to near the sinuses, 

 where they diverge and traverse the lobes of the corolla about half way be- 

 tween the margins and the axis. Anthers yellowish. Exterior envelope of 

 the achenium (calyx-tube) separable. Pappus a very short chaffy crown ; 

 the scales distinct but very thickly set, obtuse, nerveless, of nearly the same 

 texture as in Sclerolepis ; the alternate ones usually smaller and almost 

 forming an exterior series. — If the pappus alone were considered, tliis plant 



