Last year, there was a thread here concerning ID proponent Richard Buggs, who in a short paper The Deepening Of “Darwin’s Abominable Mystery”, presented a case that the geologically sudden extent of flowering plants was an ongoing problem for evolution. He expands on this in an article on his website.. A BBC article quotes him:
“One hundred and forty years later, the mystery’s still unsolved,” says Prof Buggs. “Of course, we’ve made lots of progress in our understanding of evolution and in our knowledge of the fossil record, but this mystery is still there.”
A recently published examination of a fossil, A Jurassic Flower Bud from China is relevant, dated back to 164 million years ago and so providing a much more comfortable runway to the dominance of flowering plants around 100 million years ago. A general article is here: A Newly Discovered Fossil Could Be The Answer to Darwin’s ‘Abominable’ Mystery
What I don’t know about botany could fill the oceans, so I would be interested in other’s comments on this paper. I would maintain, however, that fossils are sporadic and fortuitous, and that gaps which lend to the appearance of explosions of life may reflect more the discontinuity of the fossil record than the actual history of life. The same applies to the Cambrian explosion. The preservation of the Burgess shale and sites in China involve rare conditions and if they did not exist we simply would not know what we were missing. OTOH, new discoveries just never stop coming, and the gaps steadily narrow as the picture becomes more continuous.