IX. ALGAE. 
641 
Suborder II. Rhodosperme^e or Elorideal 
{Red or purple Algse.) 
Tribe I. Rhodomeleae. 
Rosy-red or purple, rarely brown-red or greenish-red marine Algce, flat or 
filiform. Fructification dioecious, organs of three kinds:— -1. Spores, con- 
tained in external or immersed conceptacles, or densely crowded and dis- 
persed in masses ( nuclei ) through the frond. 2. Tetraspores, red or purple, 
external or immersed in the frond, rarely contained in proper receptacles, each 
enveloped in a pellucid covering, and at maturity separating into 4 sporules, 
which are arranged crosswise or transversely. 3. Antheridia, filled with 
hyaline or yellow corpuscles {anther ozoids). 
Series A. Spores arranged on tufts of threads (articulated filaments), 
which spring together from a basal parietal or central receptacle (placenta) 
within the conceptacle. Single spores formed in all the cells of the thread, 
or in the terminal cell only. 
I. Tufts of spore-threads contained in an external ovate or spherical conceptacle. 
a. Placenta on the base of a hollow conceptacle. Spores pyriform or obconic, formed in the 
terminal cell of the spore-thread. 
Tribe I. Rhodomelese. Frond articulate or furnished with an articulated axis of 
many tubes ■ surface areolated. Spore-threads simple. Tetraspores in series in the 
branchlets, or in pod-lilce bodies (Stichidia). 
* Frond flat, proliferous {see Amansia in **). 
Frond membranous, costate, obliquely striate 32. Lenormandia. 
** Frond flat, lobed or pinnatifid. 
Frond costate, transversely striate. Stichidia on the costa . . . 33. Epineuron. 
Frond costa, transversely zoned. Stichidia marginal 34. Amansia. 
'*** Frond and branches filiform or somewhat compressed. 
t Frond inarticulate externally ; axis articulate. 
Frond laxly reticulate, closely transversely striate above ; cortical 
cells polygonal 35. Alsidium. 
Frond opaque, often compressed ; branchlets filiform, transversely 
striate; cortical cells minute, polygonal 36. Rytiphlcea. 
Frond opaque, not transversely striate. Stichidia formed of 
swollen branchlets 37- Rhodomela. 
ft Frond articulate {inarticulate in some Dasyee). 
a. frond an articulate tube, surrounded by tessellated cells. 
Tetraspores 2-seriate in terminal stichidia 38. Bostrychia. 
Frond opaque or reticulate ; joints longitudinally striate, internodes 
hyaline. Tetraspores 1 -seriate 39. Polysiphonia. 
j8. Frond with articulate unicellular branches. Tetraspore 2-oo- 
seriate in stichidia 40. Dasya. 
Ft Frond minute, filiform, articulate , bearing uniform angular 
toothed leaflets . 41. Polyzonia. 
