650 RHIZOCARPEAE. [ Marsilia, 
distant, with intervals of nearly their own width, and shorter, more ob- 
tuse than in S. Menz. and less patent; the posterior stem-leaves 2—21/2" 
long broad- tooo subcordate, obtuse, spinuloso-serrate and ciliate on 
the inner margin; the anterior ones little shorter, obliquely mucronate, 
dentate on both sides. Lateral branch-leaves nearly even-sided, decreas- 
ing visibly, the ultimate ones only */4‘’ long and twisted when nary the 
intermediate leaves '/3—1/2 of their size, suborbicular, ae mucronate, 
at last in a single file. Spikes on most branchlets, 4—10” long, the 
bracts ovate-lanceolate, acute, serrulate, patent, sine of the apex often 
sterile and foliaceous. Macrosporangia few, with a single white verru- 
culose globule; the spores of the microsporangia reddish. — Spring, l. c. 
, 184. 
Molokai! f Kalaupapa and Wailau; W. Maui! Waihee and Kaanaj pali ; 
Hawaii! (Gant, ‘Dots, Carmichael). — Typical forms distinct enough erage those of 
S. Menziesii, but they are connected by many intermediate ones which it Vv yould b 
difficult to Tete ae roperly as sor In fact there exists a gradual transition ‘tan een 
S. arbuscula, Menziesii and Spri 
Orprer XCIX, RHIZOCARPEAE. 
Sporangia of two kinds, united in one it ae at or spore fruit, or in 
separate conceptacles. Macrosporangia with a single mamillate macro- 
spore producing a small green  prothallium a female archegonia 
which remains connected with the spore. Microsporangia with 64 minute 
cell and one antheridium. — Plants floating on the water or rooting in 
mud. Leaves with or without a blade, in the latter case filiform. 
1. MARSILIA, L. 
Conceptacles on simple or tad pedicels which rise from near the base 
of the petiole, opening with two valves. Macrosporangia and microsporangia 
consociated in oblong or linear sori on transverse veins proceeding from 
e upper side or midrib of the conceptacle, two sets of sori in a con- 
ceptacle, surrounded by a gelatinous indusium; the conceptacle thus 
ce multilocular. — Leaves distichous, petiolate, circinnate in the 
bud, the blade with 4 cuneate ribless leaflets and forking veins, resem 
bling the leaf of a clover or oxalis. Rhizome creeping. 
A genus of 40—50 species, distributed over the warmer regions of the whole . 
Leaflets entire; onaag ose! single, woolly : 1. M. villos 
Leafiets emarginate: conceptacles several, pubescent ; eae © M. paren, 
1. M. villosa, Kaulf. — A. Braun, in Monatsber. k. Akad. Wiss. Berl. 
id 0, p. 653, — Rhizome villous with reddish hairs. Leaflets broad, 
entire; the petiole 4—6’ long. Only one conceptacle from the base of 
‘as ists on a peduncle shorter than its own length, both villous 
