700 
IX. ALGJE. 
\_Gigartina. 
§ 4. Frond thick , channelled-, dichoiomously or pinnately divided into cuneate or oblong 
segments ; conceptacles on tubercles on both surfaces of the fronds. 
7. G. decipiens, Hook. f. and Harv. in FI. N. Z. ii. 252. Frond 
small, cartilaginous, stipitate, flabelliform, flat, dichotomous ; segments 
cuneate, repeatedly forked, ultimate narrow-linear, acute ; axils rounded ; 
margins simple or emitting short, stout, simple or pinnate linear branchlets. 
Fructification sessile, forming scattered oblong spots over the whole frond, or 
sessile warts immersed in the tips of the branchlets. — Iri-dcea, Loud. Journ. 
Bot. 1845, 547 ; J. Ag. Sp. Alg. ii. 257. 
New Zealand, Raoul. 
8. G. stiriata, J. Ag. Sp. Alg. ii. 277 ; — FI. N. Z. ii. 252. Frond 
3-6 in. long, violet-purple, thick, fleshy, below cvlindric, stout, above com- 
pressed, slightly channelled, branched below ; branches dilating into dicho- 
tomous or subpalmate leaflets, everywhere covered with simple or branched 
papilla?, which are obovate and often foliaceous. Conceptacles wart-like, 
solitary, or crowded on the papilla?. — Mastocarpus, Kuetzing. Iridcea , Borv. 
I. volans, Mont.? Fucus, Turn. Hist. t. 16. 
Paroa Bay, Lyall. (Cape of Good Hope.) 
9. G. Radula, J. Ag. Sp. Alg. ii. 278 ; — FI. _ZV. Z. ii. 252. Frond 
fleshy, flat, somewhat channelled below, 6 in. to 2 ft. long, simple or divided 
from the base into many large stipitate, obovate-oblong fronds or leaflets, of 
a fine red or amethyst-purple colour ; margins and surfaces naked or papil- 
lose, or covered with small thick leaflets. Conceptacles subsolitary in the 
papillae.— Iridcea, Bory. Mastocarpus , Kuetzing. Fucus bracteatus, Turn. 
Hist. Fuc. t. 25. 
Abundant throughout the islands, and in Lord Auckland’s group and Campbell’s 
Island. (Throughout the Antarctic and N. and S. Pacific' Oceans.) — A most abundant and 
variable plant, assuming various shapes as it is split by the waves, etc., often perforated. 
79. IRIDJEA, Bory. 
Frond dull red, broad, flat, nerveless, between cartilaginous and fleshy ; 
central substance of densely interlaced longitudinal filaments ; cortical of 
closely packed, vertical, coloured, moniliform filaments. Spore-masses im- 
mersed in the frond. Tetraspores forming a layer at the base of the filaments 
of the periphery. 
Perennial Algce, often very large, with rough surfaces ; when cast up on the beach look- 
ing like great red-purple pieces of cloth ; found in both temperate regions. The species are 
excessively variable and difficult to discriminate. 
1. I. micans, Bory ; — Fl.N.Z. ii. 252. Frond 1-2 ft. long, ovate- 
cordate or orbicular-ovate, obtuse, shortly stipitate, dark red-purple, iridescent ; 
surface smooth ; margins and fractures ciliated, with short, simple or divided 
spines.— Bory in Voy. Coquille, 110. t. 13 and 13 bis ; J. Ag. Sp. Alg. ii. 
254. 
Akaroa and Lord Auckland’s Island, D’Urville. (Australia and all Antarctic 
shores.) 
