ACTINIOPTERIS (from aktin, a ray, and pteris, a fern; the fronds are radiately cut into narrow segments). ORD. Filices. Sori linear-elongated, sub-marginal; involucres (= indusia) the same shape as the sorus, folded over it, placed one on each side of the narrow segments of the frond, opening towards the midrib. A small genus of beautiful and distinct stove ferns. They thrive in a compost of equal parts crocks and charcoal, about the size of peas, which must be mixed with silver sand and a very small portion of loam and peat. About half the pot should be filled with crocks, perfect drainage being necessary. A moist atmosphere is also essential, and the plants may be syringed two or three times a day. A mean summer temperature of 78deg. to 80deg., with a night one of not less than 65deg., is desirable. In winter, a mean temperature of about 73deg., and a night one of not less than 60deg., should be maintained.
A. radiata (rayed).* sti. densely tufted, 2in. to 6in. long. fronds fan shaped, 1in. to 1½in. each way, composed of numerous dichotomous segments, half line broad, those of the fertile frond longer than those of the barren one. India, &c. (very widely distributed), 1869. In form this elegant little species is a perfect miniature of the Fan Palm, Latania borbonica.
A. r. australis (southern).* fronds, segments fewer, larger, and subulate at the point. Plant much larger and more vigorous.
ACTINOCARPUS (from aktin, a ray, and karpos, fruit; referring to the curiously radiated fruit, resembling a star fish). ORD. Alismaceæ. Pretty little aquatic perennials, with habit and inflorescence of Alisma. Carpels six to eight, connate at base, spreading horizontally. Excellent for naturalising in bogs and pools. Increased by seeds and divisions during spring.
A. Damasonium (Damasonium). Ray Pod. fl. white, very delicate; each petal has a yellow spot at the base; scapes with a terminal umbel. June. l. radical, on long petioles, sometimes floating, elliptical, five-nerved. A native aquatic. The proper name of this plant is Damasonium stellatum.
A. minor (smaller).* This greenhouse species, also with white flowers, from New South Wales, is smaller.
ACTINOMERIS (from aktin, a ray, and meris, a part; referring to the radiated aspect of the plants). SYN. Pterophyton. ORD. Compositæ. A small genus of herbaceous perennials allied to Helianthus, but with compressed and winged achenes. Flower-heads corymbose, Coreopsis-like. Leaves ovate or lanceolate, serrate. They are hardy, ornamental plants, and of easy cultivation, in a loamy soil. Increased in spring, by seeds and division of the roots, on a warm border, with or without hand lights, or in cold frames. With the exception of A. helianthoides, they are but little known in this country.
A. alata (wing-stalked). fl.-heads yellow. July. h. 3ft. America. 1803.
A. helianthoides (sunflower-like).* fl.-heads yellow, 2in. across, July to September. h. 3ft. S. America, 1825.
A. procera (tall).* fl.-heads yellow. September. h. 8ft. N. America, 1766.
A. squarrosa (rough-headed).* fl.-heads yellow, in loose terminal panicles. July and August. l. decurrent, broadly lanceolate, coarsely toothed. Stem square, winged. h. 3ft. North America, 1640. SYN. Verbesina Coreopsis.
ACTINOPHYLLUM. See Sciadophyllum.
ACTINOSTACHYS. Included under Schizæa (which see).
ACTINOTUS (from actinotos, furnished with rays; referring to the involucre). ORD. Umbelliferæ. An Australian genus of greenhouse herbaceous perennials. Flowers shortly pedicellate, numerously disposed in simple umbels; petals none. Leaves alternate, petiolate. They thrive best in loam and peat, and are increased by root division and seeds. The latter should be sown on a hotbed, in spring, and in May the seedlings may be transplanted out in the open border in a warm situation, where they will flower and seed freely.
A. helianthus (sunflower).* fl. white, in many-flowered capitate umbels; involucre many leaved, radiating, longer than the flowers. June. l. alternate, bipinnatifid; lobules bluntish. h. 2ft. 1821. SYN. Eriocalia major.
A. leucocephalus (white-headed). fl. white. June. h. 2ft. 1837.