Atriplex sect. Covilleiae

Plants annual, monoecious or subdioecious, glabrate. Leaves without Kranz anatomy, alternate, petiolate; blade sharply triangular-hastate or less commonly some of them entire, with overall shape ovate to lanceolate or elliptic. Staminate flowers in axillary glomerules or in naked terminal spikes. Fruiting bracteoles sessile or stipitate, mostly 3-lobed, lateral lobes rounded, united only at base, the enclosed pistillate flower with calyx of (1–)3(–5) segments. Seeds: radicle superior.

Distribution

w United States.

Discussion

Species 1.

The pattern of venation in this section is very similar to that of the closely comparable Atriplex phyllostegia, even though the veins lack the associated C4 arrangement of chlorenchyma cells surrounding the veins. The plants differ otherwise as noted in the descriptions. Placement of this species within the segregate genus Endolepis by various workers is based on two morphologic characteristics considered to be of fundamental importance, i.e., the lack of Kranz leaf anatomy and the presence of sepals subtending the ovary within the fruiting bracteoles. Sepals of staminate flowers lack the distinctive crests seen in A. [Endolepis] suckleyi, a feature on which the genus Endolepis was based. The placement of A. covillei within Endolepis, while convenient, does not take into account the overall similarity of this species to the evidently related A. phyllostegia. Neither does it take into account the potential for recurrence of sepals subtending the ovaries as possibly derived features.

Selected References

None.

Lower Taxa

Atriplex covillei