400 Transactions. — Botany. 



pinnae are opposite and similar (" pinnis in raehide filiformi 

 oppositis conformibus ") ; but Agardh is here in error — the pin- 

 nae are almost invariably unlike. Further, Agardh had not seen 

 the tetraspores : their method of division, and the fact that they 

 are often sessile, may place this plant outside the group Ptiloteoe 

 altogether. Perhaps, however, until the cystocarps are known, 

 and its position thus made more definite, it may be provisionally 

 retained here. The segmentation of the apical cell of the un- 

 limited pinnae places it in the genus Euptilota rather than in the 

 genus Ptilota. Agardh states that it is parasitic on Hymeno- 

 cladia. I have found it more often epiphytic on E. formossis- 

 sima, but also on other plants. 



Genus 9. Ballia (Harvey). 



Thallus upright, filamentous, richly generally distichously 

 branched. Main axis of a single row of cells, with opposite 

 (seldom whorled) simply or compoundly pinnate similar or 

 alternately unlike pinnules, covered below with a thickly woven 

 felt consisting of branched filaments which grow out of the 

 bases of the pinnules, also frequently coated in the lower parts 

 with rhizoids which tightly enclose the main axis. Sporangia 

 cruciate or in tetrads, terminal on the pinnules of special gene- 

 rally irregularly branched basal pinnules. Antheridia (so far 

 as is known) in small stout loose bundles on the points of the 

 ultimate pinnules. Carpogonium bearing branch, four-celled, 

 slightly bent, solitary, fastened to the basal cell of a few elongated 

 pinnules. Fertile pinnules distributed over the plant, mostly on 

 the shorter thallus branches. The auxiliary cell is developed 

 from the fertilised cell of the carpogonium branch. Cystocarps 

 generally developed in rows on the axil of a somewhat elongated 

 very shortly stalked pinnule, enclosed as by an involucre by 

 the subsequently developed richly branched basal pinnules of 

 the fertile shoot. There is a single gonimoblast which develops 

 into several or numerous rounded u;onimolobes. 



1. Ballia callitricha, J. Ag., Syst., p. 166 ( = Ballia hombro- 

 mana, Mont., Voy. au Pole sud, t. 12, f. 1. Ballia brunonis, 

 Harv., Fl. Antarct., 182. Ballia callitricha, J. Ag., Epicr. 

 Florid., p. 58). 



Root a spongy disc. Thallus densely tufted, 4-20 cm. in 

 length, with stout rigid stupose stipes, distichously pinnately 

 decompound, with the pinnae and pinnule3 opposite, similar, and 

 lanceolate in outline, and very closely set, with the last series 

 simple and more or less acute. 



The following varieties, dependent on age, are distinguished 

 by Agardh : (a) normalis, with the pinna? very densely decom- 

 poundedly pinnate, pinnules plumose ; {b) pennata, with the 



