Morphology & Anatomy of Flowering Plants: Mistakes to Avoid

Potato vs sweet potato confusion: The #1 NEET trap. Potato = stem tuber (has eyes = buds). Sweet potato = tuberous adventitious root (no buds, no nodes). Never classify potato as a root modification.
Tetradynamous vs tetramerous: Tetradynamous (4 long + 2 short stamens, total 6) belongs to Brassicaceae. Tetramerous means 4-parted flower whorls. These are completely different concepts — do not confuse.
Sieve tubes vs xylem vessels: Both may seem "dead" but sieve tubes are alive (enucleated). Xylem vessels are dead with lignified walls. The question "which is living?" has sieve tubes as the answer.
Capitulum = Asteraceae, not Fabaceae: Capitulum (head inflorescence) is the signature of Asteraceae/sunflower family. Fabaceae has vexillary aestivation, not capitulum inflorescence.
Caryopsis vs cypsela: Caryopsis (pericarp fused with seed coat) = Poaceae. Cypsela (inferior ovary fruit with pappus) = Asteraceae. Both are one-seeded dry indehiscent fruits — do not mix them.
Epicalyx ≠ calyx: Epicalyx is an extra whorl of bracteoles outside the actual calyx — only in Malvaceae (Hibiscus, cotton). Never confuse it with a second calyx or a stipule.
Ray vs disc florets in Asteraceae: Ray florets are ligulate (strap-shaped), zygomorphic, and sterile or pistillate (e.g., outer ring in sunflower). Disc florets are tubular, actinomorphic, and hermaphrodite (inner disc). Both types sit on the same receptacle.
Dicot root cambium vs monocot root: Dicot roots have cambium between xylem and phloem (allowing secondary growth). Monocot roots completely lack cambium — hence no secondary thickening ever occurs in monocot roots.
Free central placentation ≠ axile placentation: Free central has a central column with no septa (Dianthus); axile has a central axis inside a partitioned (septate) ovary (tomato, lemon). Both have ovules centrally but structurally different.
Phyllode vs phylloclade: Phyllode = modified petiole (Acacia, flat, leaf-like). Phylloclade = modified stem (Opuntia, green, photosynthetic). Different organs — do not swap.