386 Transactions. — Botany. 



(b.) GRiFFiTHSiEiE. — Thallus naked or provided with very delicate 

 verticillate ramuli. Cystocarps terminal on special fertile branches. 

 The fruit-mass of 1 or 2 gonimolobes. 



(i.) The sporangium bearing whorl of ramuli intercalary or 

 apparently terminal. Some of the ramuli sterile, 

 some fertile . . . . . . 3. Griffith-sin. 



(ii.) The sporangium bearing whorl of ramuli near the end of 

 the shoot. The inner ramuli short, branched, and 

 bearing sporangia, and enclosed by one-celled sterile 

 ramuli . . . . . . 4. Pandorea. 



(c.) Monospore^e. — Branches of a single row of naked cylindrical 

 cells. Cystocarps terminal on the fertile shoots, with 1 gonimoblast. 

 (i.) Sporangia divided into more than 4 spores 



5. Pleonosporium. 



(d.) Callithamnie^:. — Main axis of a single row of naked cells, the 



lower part clad with rhizoids. Cystocarps lateral, without involucre. 



(i.) Sporangia divided into tetrads. Fruit-mass of several 



rounded gonimolobes . . . . 6. CaUithamnion. 



(e.) Spongoclccsie.e. — Main shoot naked, covered with a spongy 

 network of long-celled laterally-branched filaments. Cystocarps ter- 

 minal on very short lateral branches, thus appearing" sessile. Cyst- 

 ocarps of several rounded successively formed gonimolobes, some- 

 times enclosed in a small-celled patelliform involucre. 



(i.) Thallus round, covered with a spongy network. The 

 central axis branched alternately at the joint-cells, 

 not coated with rhizoids. Cystocarps external on the 

 network of the thallus, closed on the underside by the 

 filaments, without patelliform involucre 



7. Spongoclonium. 



B. Ptilote^e. — Cell rows of the branches naked or with ramuli. Thallus 



either coated with rhizoids or with a normal closed cortex. Cysto- 

 carps generally enclosed by several involucral branchlets. 



(i.) Branches coated with rhizoids or with a normal cortex. 

 Apical cell diagonally segmented. Cystocarps terminal on 

 short fertile pinna? . . . . . . 8. Euptilota. 



C. Crouanieje. — Main axis either of a single row of cells with very richly 



branched ramuli, or with a central axis and cortex, consisting of 

 richly branched filaments tightly packed together. 



(i.) Thallus filamentous, main shoot consisting of a single row of 

 cells. Cystocarps in the axil of a solitary ramulus 



9. Ballia. 



(ii.) Thallus filamentous, main shoot consisting of a single row of 



cells. Cystocarps terminal . . .. 10. Antithamnion. 



D. Spyridieje. — The thallus possesses a central axis which is completely 



or partially clothed with a cortex consisting of larger cells within and 

 smaller cells without. 



(i.) Thallus rounded, branched on all sides, with large-celled 

 central axis. The cortex ring internally large-celled, 

 externally small-celled, and broken only on the weaker 

 shoots .. .. .. ..11. Spyridia. 



(ii.) Thallus rounded or flattened, dichotomously branched, the 

 dichot onions branches bent inwards like a pair of pincers. 

 Central axis large-celled. Cortex ring continuous, or found 

 only at the nodes .. .. .. 12. Cera mi urn. 



(iii.) Thallus completely corticated, with conspicuously large cells 

 internally and small externally . . .. 13. Micmr/adia. 



E. Thallus filamentous with creeping rhizoids and erect fertile branchlets. 

 Branches consisting of single rows of cells .. 14. Rhndocorton. 



