Pennaria disticha Goldfuss, 1820

Stems plumose, arising from a ramified hydrorhiza; stolons tubular, perisarc very thick, internally longitudinally striated.

Hydrocaulus tubular, becoming narrower distally, divided into internodes of variable length by 4-5 deeply indented transverse nodes; hydrocladia distal on internodes, gracefully recurved from stem, up to eight annulations at junction with stem; internodes same as those on stem, one hydranth given off on a short expanding pedicel on upper, distal side of each internode; pedicel indistinctly ringed at base, perisarc thinner than on hydrocladium.

Hydranths clavate to pyriform, terminal hydranth on each hydrocladium usually larger than others, all hydranths with a whorl of 10-14 semi-filiform aboral tentacles and 14-16 scattered pedunculate capitate tentacles on upper body, aboral tentacles with a longitudinal band of nematocysts on outward facing side, peduncle of oral tentacles long, transversely wrinkled, capitulum richly armed with nematocysts.

Cnidome:

i) Stenoteles, capsule ovoid, 45 -46 x 27-30 µm, shaft 58-60 µm, 10 µm wide armed with four or five curved spines 30 µm long spines and spirals of fine bristles, tubule at least 180 µm long; abundant in capitate tentacles.

ii) Stenoteles, capsule ovoid, 37 x 25 µm, shaft 60 µm, tubule at least 60 µm, in capitate tentacles; none discharged, not common.

iii) Stenoteles, capsule ovoid, 15- 18 x 13- 17 µm, shaft 15-20 µm; in capitate tentacles.

iv) Stenoteles, capsule ovoid, 6.5-10 x 4-7 µm shaft 8 µm, very abundant; in aboral and capitate tentacles, few discharged.

v) Desmonemes ovoid to pyriform capsules, 6-8 x 4-4.5 µm, in aboral tentacles, only one seen discharged.

vi) ?Haploneme, capsules small bean shaped, 9- 12 x 3-6 µm; abundant in aboral tentacles, none discharged.

vii) Capsule ovoid narrower at anterior end, 12.5-15 x 6.5-7 µm with inclusion body; in aboral tentacles, none discharged.

viii) ?Isorhiza capsule almost spherical 10 x 7 µm, site unknown, several partially discharged, tubule with very fine spines.