In the case of twins, "'dichorionic placentation "'refers to the presence of two placentas ( in all dizygotic and some monozygotic twins ) . "'Monochorionic placentation "'occurs when monozygotic twins develop with only one placenta and bears a higher risk of complications during pregnancy.
42.
This process is highly regulated due to detrimental consequences that can arise from aberrations of the placentation process : poor infiltration of the trophoblasts may result in preeclampsia while severely invasive trophoblasts may resolve in placenta accreta, increta or percreta; all defects which most likely would result in the early demise of the embryo and / or negative effects upon the mother.
43.
"Hasseltia " is unique among Salicaceae in that the species have pseudo-axile placentation, compound umbellate inflorescences, and a pair of glands embedded in the base of the leaf blades . " Hasseltia " is now classified in Salicaceae, along with close relatives " Pleuranthodendron " and " Macrothumia ", with which they are commonly confused.
44.
Vm8 10 the formula of " Tamarindus indica "; bract and petaloid bracteoles; monosymmetric calyx of three and two petaloid sepals; monosymmetric corolla of three and two reduced petals; two whorls of stamens, the outer monosymmetric from three fused and two reduced stamens, the inner of 4 reduced and 1 lost stamen; monosymmetric gynoecium of 1 carpel with superior ovary; marginal placentation with 8 10 ovules per gynoecium.
45.
Maheshwari and Johri ( 1956 ) conducted an extensive investigation of the morphology of " Floerkea " noting that, among other things, the herbaceous habit, gynobasic style, unusual type of tetrasporic embryo sac and basal parietal placentation of the unitegmic, tenuinucellate ovules differ from the Geraniales which has among its woody to herbaceous members, ( at most ) lobed syncarpous gynoecia, monosporic embryo sacs, generally axile placentation and bitegmic, crassinucellate ovules.
46.
Maheshwari and Johri ( 1956 ) conducted an extensive investigation of the morphology of " Floerkea " noting that, among other things, the herbaceous habit, gynobasic style, unusual type of tetrasporic embryo sac and basal parietal placentation of the unitegmic, tenuinucellate ovules differ from the Geraniales which has among its woody to herbaceous members, ( at most ) lobed syncarpous gynoecia, monosporic embryo sacs, generally axile placentation and bitegmic, crassinucellate ovules.
47.
The core Caryophyllineae sub-order is well-supported with numerous distinctive synapomorphies, such as : 1 ) sieve tubes of phloem with plastids with peripheral ring of proteinaceous filaments ( often with a central protein crystal ), 2 ) presence of betalains, 3 ) loss of the rpl2 intron in cpDNA, 4 ) single whorl of tepals, 5 ) pollen with spinulose and tubiliferous / punctuate exine, 6 ) placentation free-central to basal, curved embryo, and 7 ) presence of perisperm with endosperm scanty or lacking
