82 
20. THASPIUM Nutt. Genera, i. 196. — Perennials (2 to 5 
feet high), with ternately divided leaves and broad serrate or 
toothed leaflets (or lower leaves simple), mostl}^ no involucre, in- 
volucels of small bractlets, mostly yellow flowers, and all the fruits 
pedicelled. 
The species of Thaspium are in great confusion. In Gray’s Manual 
T. aureum Nutt, and T, trifoUahim Gray each have an apterous variety. 
These apterous forms were taken from Koch’s genus Zizia and placed 
under the Thaspium species apparently from the close resemblance of the 
foliage, The fruit characters, however, are abundantly distinct, for the 
Zizia forms have simply ribbed fruit flattened latterally, the central fruit of 
the umbellets sessile, and flower in early spring; while T. aureum and 
r. iri/oh'a/ttTO of the Manual have winged fruit flattened dorsally, central 
fruit pedicelled, and flower lat(' in summer, maturing fruit in the fall. 
Bentham & Hooker have transferred these apterous Zizia forms to a sec- 
tion Zizia under Carum, from which genus they differ in the absence of 
stylopodia, central sessile fruit, more prominent ribs, and Thaspium-Vike 
foliage. The same authors seem to have made no disposition of 2'. aureum 
of the Manual, unless it went with the apterous variety, while the group Of 
forms under T. trifoliaium Gray, of the Manual, has been taken to represent 
T. cordaium Torr. & Gray. For this latter species Bentham & Hooker 
seem to have had in mind only Gray’s apterous variety, and so referred it 
to Carum § Zizia as one of the two species. In Watson’s Bibliographical 
Index the synonym Carum cordaium Hoaih. & Hook, under T. trifoliatum, 
is correctly quoted so far as literature is concerned, but apparently should 
be transferred to T. trifoliaium, var. apterurn Gray, to express the real 
form Bentham & Hooker had in mind. This leaves the Manual forms T. 
aureum and T. trifoliatum with its var. atropurpureum unprovided for by 
these authors, the two apterous varieties only having been used to form 
the section Zizia under Carum. An explanation of this may be found in 
the fact that most of the herbarium specimens labeled Thaspium aureum 
are really the so-called apterous varieties. The true Thaspium forms, with 
winged fruit, are quite uncommon in herbaria, while the apterous forms 
are very abundant. 
1. T. aureum Nutt. l.c. Glabrous: radical leaves mostly cor- 
date, serrate: stem leaves simply ternate (rarely biternate); leaflets 
ovate to lanceolate, rounded or tapering at base, serrate: umbels 8 
to 12-rayed; rays ^ to 1 inch long; pedicels about a line long ; 
flowers deep yellow: fruit globose-ovoid, about 2 lines long, all 
tbe ribs equally winged. (Fig. 85.) 
Thickets and woodlands, throughout the Atlantic States and westward 
into the Mississippi Valley. Apparently not in Canada, all the specimens 
so labelled from there being Zizia aurea- FI. in summer and maturing 
fruit in late summer or autumn. 
