Rhodanthe, now so common, and several unpublished plants, of new genera, the more remarkable of which are the following; viz. Lawrencella rosea,94 a most beautiful annual, resembling Rhodanthe, but handsomer, and differing in the achænia being covered with long clavate glands, and in the pappus not being plumose; from the greater part of the allies of Rhodanthe it is distinguished by the pappus being in many rows; Xyridanthe,95 another genus near Rhodanthe, from which it differs in the pappus being paleaceous and plumose, not setose: the species are annuals of no beauty; and Pithocarpa,96 a very curious genus, of which there are two rather pretty species; it is near Humea in character, but entirely different in habit. To these has to be added Rhytidanthe and Ixiolæna, Benth., genera with which I am unacquainted.
(94) Lawrencella Helichryseæ), Capit. multiflorum homogamum. Involucrum hemisphæricum, imbricatum; squamis exterioribus herbaceis sphacelatis interioribus petaloideis radiantibus. Receptaculum planum nudum. Cor. 5-dentatæ. Antheræ ecaudatæ. Stigmata conica dorso glandulosa. Achasnia erostria, compressa, glandulosa. Pappus multiserialis, setosus, æqualis; setis serratis. Antheræ certe ecaudatæ et basi rotundatæ, sed fills quibusdam arachnoideis tenuissimis loco caudæ colligatæ.
Lawrencella rosea. Herba annua, glanduloso-subpubescens. Folia opposita et alterna, linearia, obtusa, indivisa. Pedunculi axillares et terminales, monocephali, lanati. Involucri squamæ ext. ovatæ, acutæ, margine lanatæ; interiores elongatæ, apice subdentatæ, amœnè roseæ.
(95) Xyridanthe (Helichryseæ). Capitulum multiflorum homogamum. Involucrum campanulatum, imbricatum; sq. ext. concavis rotundatis subscariosis, interioribus radiantibus apice appendice petaloidea auctis. Receptaculum planum nudum. Cor. 6-dentatæ. Antheræ pilis arachnoideis caudatæ. Stigmata truncata. Achænia erostria, lanata. Pappus paleaceus, biserialis, corolla longior; paleis plumosis.
Xyridanthe stricta. Herba annua, glaberrima. Folia alterna, oblongo-lanceolata, membranacea, sessilia. Rami stricti, monocephali, pedunculo omnino nudo. Capit. 2½ lin. longa, fusca, nitentia, Xyridis capitulum referentia; squamis oblongis obtusis, interioribus appendice brevi albâ radiante.
(96) Pithocarpa ((Helichryseæ). Capitulum multiflorum, homogamum. Receptaculum conicum nudum. Involucrum turbinatum, multiseriale, imbricatum; squamis exterioribus subulatis, intimis petaloideis radiantibus. Corolla tubulosa, 5-dentata. Antheræ lana tenui baseos cohærentes. Achænium erostre, oblongum, calvum, pubescens.
Pithocarpa pulchella. Sesquipedalis, herbacea, lanugine deciduâ tenui vestita. Caulis paniculatus parùm ramosus, quasi aphyllus: foliis lineari-lanceolatis sublanatis sessilibus, distantibus. Ramuli 2-3 poll. longi, monocephali, ascendentes, squamis parvis linearibus distantibus vestiti. Involucri basi sublanati squamæ exteriores purpureo apiculatæ, interiores candidæ, obtusæ.
(97) Pithocarpa corymbulosa; ramis elongatis apice corymbosis, involucri sublanati squamis exterioribus scariosis acutis.
