156 Rhodora [SEPTEMBER 
Pilinia endophytica n. sp. For several years the writer has been 
puzzled by a small green alga, endophytic in Ralfsia Borneti Kuckuck, 
a common Ralfsia along the New England coast on live mussels and 
Lithothamnion in tide pools, occasionally occurring on rocks. In July 
of the present year, while the writer was dredging in Harpswell Sound, 
Maine, a stone was brought up from about five meters depth at low 
water, on which was a growth of Ralfsia, in which the endophyte 
occurred rather more abundantly than usual; while the description 
that can now be made leaves something to be desired, at least it can be 
put on record and attention called to the plant, so that further investi- 
gation can be hoped for. It may be characterized as follows:— 
Fronde formae indefinitae, filamentorum plerumque brevium, 
simplicium vel ramosorum, sistente, inter filamenta plantae hospitis 
serpentium; cellulis quoad formam et magnitudinem variantibus, 
cylindricis, clavatis, subsphaericis, vel irregularibus, 7-22 и diam., 
1-5 diam. longis; chromatophora laete virente, cellulam complente, 
vel plerumque cupuliformi, partem superiorem cellulae occupante. 
Sporangiis terminalibus, sphaericis vel ovoideis, ad 30 y diam., sporas 
numerosas foventibus. 
Frond of no definite form, consisting of usually short, simple or 
branched filaments, creeping among the filaments of the host; cells 
variable in form and size, cylindrical, clavate, subspherical or irregu- 
lar, 7-22 н diam., 1-5 diam. long; chromatophore light green, some- 
times filling the cell, more commonly cup-shaped, at the upper end of 
the cell. Sporangia terminal, spherical or ovoid, up to 30 y diam., 
containing numerous spores. In fronds of Ralfsia Borneti Kuckuck, 
Harpswell, Maine, July, 1908. Type in herb. F. 5. С. 
The placing this species in the genus Pilinia might be considered 
somewhat intuitional, as the vegetative characters are so vague; but 
imperfect and stunted as the filaments are, their appearance recalls 
that of undoubted Pilinia species. The occurrence of the terminal 
sporangium seems to confirm this, but the form must be regarded as 
greatly modified by the endophytic habit. АП distinction between 
vertical and horizontal filaments is lost, and the cells are very irregular 
in shape and size; sometimes a filament will be found of six or seven 
cylindrical or slightly clavate cells, 2-5 diam. long, quite as in typical 
Pilinia species, but this is unusual. Whether the sporangia produce 
zoospores or aplanospores could not be determined. The nearest 
relation of this species would seem to be P. minor Hansg. If we may 
imagine a descent from the latter, from living free on pebbles to living 
