- Blue markers: specimen records
- Yellow marker: type locality, if present
- Red markers: endpoints of range from literature
Prionitis J. Agardh 1851
Thalli erect, 1 or more axes arising from discoid holdfasts. Axes terete below and compressed above, or terete or compressed throughout. Major branches approximately same breadth throughout, dichotomously or irregularly divided. Lateral margins of major secondary branches frequently with numerous peglike to foliar proliferations; branches lying in same plane, appearing pinnate. Surface of thallus smooth. Medulla of densely interwoven filaments. Cortex of small, tightly packed cells in deep rows. Transitional area between medulla and cortex sometimes with stellate cells. In general, medulla twice as thick as cortex (in Carpopeltis bushiae, thickness of medulla equal to that of cortex). Tetrasporangia cruciately divided, isolated in cortex or grouped in small sori. Spermatangia in extensive, whitish, superficial sori covering both surfaces of branches. Carpogonial branches 2-celled, arising in small cluster of sterile filaments; auxiliary cell intercalary, immersed in small, branched cluster of sterile filaments. Connecting filament necessary for transfer of diploid nucleus. Gonimoblasts in groups, modifying thallus externally, borne on internal stalks formed by fused basal cells of gonimoblast. Gonimoblast filaments developing toward surface, nearly all cells but basal ones becoming carposporangia, surrounded by sterile filaments.
Prionitis lyallii Harv. Harvey 1862: 173; Smith 1944: 247. Prionitis andersonii J. Agardh 1876: 159; Smith 1944: 246.
Thalli 20-35(75) cm tall, brownish to bright brick-red; stipes 1-10 mm diam., 2-70 mm long, little divided or dichotomously divided 3 or 4 times; stipes giving rise terminally to several generally lanceolate blades, these 1-5 cm wide, 3-45(60) cm long; occasionally stipes gradually grading into a broadened, nonfoliar portion throughout length of plant; primary blades frequently bearing irregular, narrowly stipitate, secondary and tertiary blades; blades firm or soft to slippery, rarely with marginal proliferations; tetrasporangia in modified nemathecia in blades; gonimoblasts scattered throughout blades, 1-1.5 mm diam., conspicuous for genus.
Common, on low intertidal rocks covered with coarse sand, to subtidal (to 35 m), Esquimalt (Vancouver I.; type locality), Br. Columbia, to Pta. Maria, Baja Calif.
Several forms of this common species have been recognized by Harvey and also by Setchell and Gardner. These authors realized, however, that the forms grade into each other. At the present, although we have more specimens from a wider variety of habitats and geographical ranges, these forms cannot be distinguished, as has been done with P. lanceolata. As with that species, it is almost impossible to choose a "typical" specimen.
Excerpt from Abbott, I. A., & Hollenberg, G. J. (1976). Marine algae of California. Stanford University Press, Stanford, California. xii [xiii] + 827 pp., 701 figs.
NATIVE
Type locality: west coast of Mexico or USA
