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Green Algae of Zihuatanejo

PHYLUM CHLOROPHYTA

-Plants (Kingdom Plantae)

-Green Algae (Phylum Chlorophyta)

-Ulvophycean Green Algae (Class Ulvophyceae)

-Order Bryopsidales

-Family Caulerpaceae

-Genus Caulerpa

-Flattop Seagrape (Caulerpa chemnitzia)


Caulerpa chemnitzia, commonly known as flattop seagrape, is a tropical green macroalga characterized by upright fronds that resemble miniature clusters of flattened grapes. The plant consists of creeping, root-like stolons that spread across sandy or rocky substrates, anchoring it with rhizoids while sending up short vertical blades topped with rounded to somewhat flattened, disc-like ramuli (the “grapes”). Its bright to deep green coloration reflects its chlorophyll-rich tissues, and like other species in the genus, it is a siphonous alga—meaning the entire organism is essentially one large multinucleate cell without internal cross walls. Caulerpa chemnitzia is commonly found in shallow coastal waters, seagrass beds, and reef flats in tropical and subtropical regions.

Flattop Seagrape
(Caulerpa chemnitzia)

Range

  • Widely distributed throughout the tropical and subtropical Indo-Pacific and the tropical eastern Pacific.

  • In the eastern Pacific, it occurs from the Gulf of California south along the Pacific coast of Mexico, Central America, and South America, including the Galápagos Islands.

  • Common along the Pacific coast of Guerrero, including the Zihuatanejo region.

Habitat

  • Grows on rocky reefs, coral reefs, reef flats, tide pools, sandy bottoms, and coral rubble.

  • Commonly found from the intertidal zone to depths of about 30 m (100 ft).

  • Attaches to hard surfaces using creeping stolons with numerous root-like rhizoids, often forming dense underwater meadows.

Size

  • Frond height: 5–25 cm (2–10 in)

  • Stolon length: Often exceeds 1 m (3.3 ft) as colonies spread across the substrate.

  • Individual feather-like branches are typically 2–10 cm (0.8–4 in) long.

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