page_title: Caltha obtusa
section_title: Description
hierarchical_section_title: Caltha obtusa / Description
caption_attribution_description: English: pollen of Caltha obtusa, in polar view
context_page_description: Caltha obtusa, commonly known as white caltha, is a small, perennial herbaceous plant belonging to the family Ranunculaceae, that grows in open vegetations in mountainous areas, and is endemic to New Zealand’s South Island.
context_section_description: Caltha obtusa is a small (2–6 cm high), hairless, perennial herb. Plants form mats of rosettes. Its white rhizomes are stout and fleshy. The spade-shaped leaves have slender petioles of 8–12 mm long that form a membranous sheathing base. The leafblade is dark green to yellowish green and sometimes with bronze blotches or streaks, are 8-12 × 7½-11 mm with two lobes at its base, with an indent at its tip and deeply scalloped edges, particularly near the base. The basal lobes (or appendages) are mostly pressed against the upper surface of the leaf, are more than half as long and also have a deeply scalloped outer margin. The five white sepals are 8–18 mm long and 6–12 mm wide, obovate, widest between the tip and the middle, and have an obtuse to acute tip. There are between ten and fifteen stamens encircling free narrow-ovate carpels each about 4–5 mm long and topped by a rather long and slender style. Flowers are said to smell like lemon. The fruiting heads are 12–18 mm across. Follicles reach 1¼-1½ cm in length. Seeds may ripen seldomly. Flowering occurs between December and February, and fruits can be found from February until April. There are forty eight chromosomes (2n = 48).
caption: The tricolate pollen, polar view, showing the three characteristic slits
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