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This photo includes all species of Bothriochloa known from Oklahoma except for B. barbinodis (assuming B. lagaroides subsp. lagaroides doesn't occur here and no other splits have occurred since I last checked).

Top-left (1st of individual rames): B. bladhii
Top-right (2nd of individual rames): B. lagaroides subsp. torreyana
Bottom-left (3rd of individual rames): B. ischaemum var. ischaemum
Bottom-right (4th of individual rames): B. ischaemum var. songarica

I left my Flora of Oklahoma on campus and my Grasses of Texas is loaned out, so I used Vega (2000), REVISIÓN TAXONÓMICA DE LAS ESPECIES AMERICANAS DEL GÉNERO BOTHRIOCHLOA (POACEAE: PANICOIDEAE: ANDROPOGONEAE). Powell and Worthington (2018) don't recognize the varieties citing Allred (Flora of North America). Allred provides no explanation for this decision. From this small sampling, the two varieties seem quite distinct and occur in abundance sympatrically without intermediacy. Though, it is the collar of the leaves that are hairy here and not the nodes. Because the two forms are so distinctive, I'll go ahead and keep using the names until I find some evidence to suggest I shouldn't. As for B. lagaroides subsp. torreyana, it seems the justification originates from Nueva Combinación en Bothriochloa Kuntze (Poaceae). My Spanish isn't all that great, so I'll refrain from comment. I'll only say that I don't think the combination has been picked up in any local sources. Similarly, BONAP hasn't picked up the change. POWO cites GrassBase. GrassBase cites an article I either couldn't find or doesn't seem to apply. Tropicos cites the article above for the new combination.

Photos 1-3 compare D. lucidum (left) with D. microcarpon (middle) and D. dichotomum var. dichotomum (right).

It co-occurs and mingles with microcarpon, and its leaf proportions can be very similar to the autumnal leaves of micro. However, D. lucidum lacks bearded nodes (the lowest one may have some hairs) and its leaves are consistently sized; micro has conspicuously larger vernal leaves. It also has thinner, wirey culms and it has a more horizonal/creeping habit.

D. dichotomum var. dichotomum is more of an upland species and is unlikely to closely associate, but it can occur in uplands adjacent to seeps and is also visually similar. dichotomum has a strictly upright habit, proportionately longer/narrower leaves, and wider culms; its leaves are also held differently (more regular and parallel to the ground?).

Comparison of five species of Dichanthelium, from left to right: D. sphaerocarpon, D. boscii, D. commutatum var. commutatum, D. commutatum var. ashei, D. dichotomum var. dichotomum.

Images compare the spikelets, lowest node, widest leaf, and overall habit.