12 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



20. Gland cells absent 26 



21. Branch tips pointed 22 



21. Branch tips blunt 23 



22. Rhizoids multiple and compound from a node; gland 



cells on three cells 



A. cristirhizophorum Tokida & Inaba 



22. Rhizoids solitary and simple from a node; gland cells 

 on two cells A. hubbsii sp. nov. 



23. Determinate lateral branches mostly simple in upper parts 

 A. simulans Gardner 



23. Determinate lateral branches mostly branched in upper parts 24 



24. Determinate laterals with opposite branchlets 



A. pulchellum Gardner 



24. Determinate laterals alternately branched 25 



25. Indeterminate axes all creeping; determinate branches all 



ascending and dorsally erect from creeping axes 



A. Iherminieri (Cr. & Cr.) Nasr. 



25. Some determinate axes free and erect; determinate branches 

 essentially paired, opposite and bilateral at each node, but the 

 pairs commonly spiraling A. sublittorale Setch. & Gard. 



26. Plants with a loose, pseudocortical band around lower 

 nodes consisting of appressed, incurved and clasping 



secondary lateral branchlets 



A. pseudocorticatum sp. nov. 



26. Plants without any pseudocortication 27 



27. Tetrasporangia pedicellate; thallus reaching more than 5 cm 

 high (sometimes up to 20 cm) and main axes over 80 /x in 

 diameter 28 



27. Tetrasporangia sessile; thallus under 1 cm high, the main 

 axis 30-40 jx in diameter A. palmyrense Dawson 



28. Branches recurved and causing entangling of the thallus 



parts to provide a ropedike appearance 



A. uncinatum Gardner 



28. Branches not recurved, without ropedike appearance .... 29 



29. Terminal cells of branchlets blunt 30 



29. Terminal cells of branchlets acute 33 



30. Tetrasporangia in pedicellate clusters from each bearing 

 cell ; basal cell of determinate laterals much shorter than 

 others A. pacificum 



