272 RYDBERG: SOME GENERIC SEGREGATIONS 
we must, if consistent, divide Zygadenus into at least three genera. 
Briefly these may be distinguished as follows : 
Plant with a rootstock ; each petal and sepal with two glands. Zygadenus. 
Plant with a bulb; each petal and sepal with a single gland. 
Ovary wholly superior ; gland obovate or semi-orbicular. Toxtcoscordton. 
Ovary partly inferior ; gland obcordate. Anticlea. 
ZYGADENUS Michx. Fl. Bor. Am. 1: 213. 1803 
This genus was established on a single species 7. glaberrimus 
and the generic name will go with it. This species differs from all 
that later have been included in the genus, in having a thick elon- 
gated rootstock instead of a bulb and two distinct round glands 
on each of the petals and sepals. As far as I know the genus 
consists of only one species. 
Toxicoscordion gen. nov. 
Glabrous, more or less poisonous perennials with narrow linear 
conduplicate leaves, yellowish racemose or paniculate flowers and 
membrane-coated bulbs. Flowers perfect (in one species described 
as polygamous, but as far as I know erroneously so). Petals and 
sepals bearing a single obovate or semiorbicular gland at or above 
the base of the blade, in most species more or less clawed. Ovary 
wholly superior. Stamens (except in one species) more or less 
adnate to the base of the petals and sepals ; anthers subreniform, 
confluently one-celled. Capsule 3-celled, 3-beaked, septicidal. 
Seeds numerous. 
The first species known belonging to this group was published 
under the name Avmzanthium Nuttall A. Gray ; but as this is 
somewhat aberrant from the general type of the genus, I have 
selected one of the most common species, Zygadenus intermedius, 
as the type. The following species belong here : 
1. T. intermedium ; 2. iztermedius Rydb.* 
2. T. venenosum (S. Wats.) ; Z. venenosus S. Wats. 
3. T. gramineum ; 7. gramineus Rydb. 
4. T. acutum; Z. acutus Rydb. © 
5. T. faleatum ; 2. falcatus Rydb. 
6. T. paniculatum (Nutt.); Helonias paniculata Nutt. 
7. T. Nuttallii (A. Gray); Amianthium Nuttallii A. Gray. 
* For citations and synonyms, see Bull. Torrey Club, 27: 534-538. 1900. 
