Section

Series

Species

Subspecies

(2n=)

I. ANNUUI

*niveus

niveus, tephrodes, canescens

34

*debilis

debilis, vestitus, tardilorus, silves-tris, cucume-rifolius

34

*praecox

praecox, runyonii, hirtus

34

*petiolaris

petiolaris, fallax

34

*neglectus, *annuus, *argo-phyllus, *bolanderi, *anomalus, *paradoxus, *agrestis

34

II. CILIARES

1. Pumili

gracilenthus, pumilus, cusickii

34

2. Ciliares

arizonensis, laciniatus

34

ciliaris

68

III. DIVARICATI

1. Divaricati

mollis, divaricatus, decape-talus

34

occidentalis

occidentalis, plantagineus

34

hirsutus, strumosus

68

eggertii, tuberosus

102

rigidus

rigidus, sub-rhomboideus

102

2. Gigantei

giganteus, grosseserratus

34

nuttallii

nuttallii, parishii, rydbergii

34

maximiliani, salicifolius, cali-fornicus

34

resinosus, schweinitzii

102

3.Microcephali

microcephalus, glaucophyllus, smithii, longifolius

34

laevigatus

68

4. Angustifolius

angustifolius, simulans, floridanus

34

5. Atrorubentes

silphioides, atrorubens, hetero-phyllus, radula, carnosus

34