Pollen morphology ofDeinostema,Geochorda,Gratiola,Ildefonsia,Sophronanthe, andTragiola(Scrophulariaceae, Gratioleae, Gratiolinae)

摘要

The pollen grains ofDeinostema,Geochorda,Gratiola,Ildefonsia,Sophronanthe, andTragiolaare single, isopolar to anisopolar, and radially symmetrical, with three or four equally spaced meridional colpi. Pollen grains ofIldefonsiaandGeochordaare semitectate with a relatively well-developed to intermediate sexine 1 (interstitium). InIldefonsiathe sexine 2 (tectum) is comprised of a complex network of vertically overlapping, interwoven muri, and a baculate sexine 3 is present. InGeochordathe muri are not vertically interwoven and the sexine 3 is absent. The grains ofDeinostema,Gratiola,Sophronanthe, andTragiolaare tectatendash;perforate, lack a baculate sexine 3, and have a reduced to intermediate sexine 1. All of the taxa examined exceptGeochordaare distinguished from the Mimulinae by pollen morphology. The pollen evidence inDeinostema,Gratiola,Sophronanthe, andTragiolacorrelates with the floral data and is consistent with a mutual relationship among these genera. The pollen grains ofGeochordaandIldefonsiaare distinct from one another and from those of the other genera examined. Pollen of the latter is of a morphotype not previously reported in tribe Gratioleae.