The Cactaceae. Britton & Rose 1922.

<25. FRAILEA gen. nov.

Plants small, globular or cylindric, with the apex rounded or depressed, usually cespitose; ribs numer­ous, low, divided into tubercles, these bearing small spines; flowers small, often cleistogamous, arising from the apex of the central tubercles; fruit small, spherical to ellipsoid, bearing narrow yellow scales with hair-like bristles in their axils, these forming a crest to the flower; seeds black or brown, smooth or pub­escent, shining, with a triangular, deeply concave face; embryo straight ( !), splitting the testa on the back of the seed in germinating; endosperm wanting; cotyledons minute, if at all developed.
Type species: Echinocactus cataphractus Dams.
These plants very much resemble some of the small species of Mammillaria, but the low tubercles are more definitely arranged on ribs and the flowers and fruit are very different; the seeds are much like those of Epithelantha, but the flowers are different and the fruit is scaly. The flowers of this genus are not very well known; several of the species have been described as having the flowers often cleistogamous and it may be that they all are. We have had two or three of the species under observation for several years. Flower-buds are often formed and occasionally ripe fruit with fertile seed is produced, but we have never seen open flowers or in­dications that they had opened. The flowers may open at night, but we doubt it; they certainly do not in day-light.
While the species of this group which we know from living plants clearly represent a very distinct generic type, we are not quite certain whether Echinocactus caespitosus belongs here or not. Its larger flowers suggest a possibility of its being related to Malacocarpus and indeed Spegazzini states that it is near E. concinnus.
The genus is named for Manuel Fraile who was born at Salamanca, Spain, in 1850, and who for years has diligently cared for the cactus collection in the U. S. Department of Agri­culture, Washington, D. C. Eight species are recognized.

Key to Species.

Stems cylindric, usually simple						1. F. gracillima
Stems globular, more or less cespitose.
	Seeds puberulent					2. F. grahliana
	Seeds smooth.
		Ribs more distinct than in the other species				3. F. pumila
		Ribs very indistinct.
			Radial spines 12 to 14			4. F. schilinzkyana
			Radial spines 5 to 9.
				Plants usually simple; fruit red		5. F. cataphracta
				Plants cespitose; fruit black		6. F. pygmaea
						7. F. caespitosa
Uncertain relationship						8. F. knippeliana

1. Frailea gracillima (Lemaire).

Echinocactus gracillimus Monville in Lemaire, Cact. Gen. Nov. Sp. 24. 1839.
Echinocactus pumilus gracillimus Schumann, Gesamtb. Kakteen 394. 1898.

Cylindric, simple, 10 cm. high, 2.5 cm. in diameter, grayish green; ribs about 13, but indistinct, more or less spiraled, tuberculate; areoles small, with a purple blotch beneath each one; radial spines about 16, setaceous, white, 2 mm. long, more or less appressed; central spines 2 to 4, more or less unequal, 4 to 8 mm. long; flowers yellow, 3 cm. long; scales on the ovary and flower-tube woolly and bristly in their axils; fruit 6 mm. in diameter; seeds 1.5 mm. long.
Type locality: Not cited.
Distribution: Paraguay.
Echinocactus gracilis (Forster, Handb. Cact. 304. 1846) is given as a synonym of this spe­cies, but was not described. This is probably the E. gracilis Lemaire of collections (Monatsschr. Kakteenk. 10: 16. 1900).
Illustration: Monatsschr. Kakteenk. 9: 55, A, as Echinocactus gracillimus.

2. Frailea grahliana (Haage jr).

Echinocactus grahlianus Haage jr. in Schumann, Monatsschr. Kakteenk. 9: 54. 1899.
Cactus grahlianus Kuntze, Deutsch. Bot. Monatsschr. 21: 193. 1903.

Cespitose; plants small, depressed-globose, 3 to 4 cm. in diameter; ribs about 13, low and indistinct; spines all radial, 9 or 10, subulate, appressed, somewhat curved backward, 3.5 mm. long; flowers 4 cm. long, yellowish; fruit 6 mm. in diameter; seeds brown, puberulent.
Type locality: Paraguari, Paraguay.
Distribution: Parayuay; also Argentina, ac­cording to Spegazzini.
Echinocactus grahilianus adustior (Monats­schr. Kakteenk. 14: 156. 1904) is only mentioned.
Illustrations: Schumann, Gesamtb. Kakteen Nachtr. f. 20; Monatsschr. Kakteenk. 9: 55, B; 12: 141, as Echinocactus grahlianus.

3. Frailea pumila (Lemaire).

Echinocactus pumilus Lemaire, Cact. Aliq. Nov. 21. 1838.

Plant cespitose, small, globose, umbilicate at apex, deep green, sometimes becoming reddish; ribs 13 to 15, more distinct than in the related species, more or less tuberculate; areoles small, nearly circular; spines all pubescent, yellowish brown; radial spines 9 to 14, set­aceous, more or less appressed; central spines 1 or 2, flower 2 cm. lone, yellow; axils of scales on the ovary and flower-tube woolly and setose; seeds smooth, brown, obovate, 1.5 mm. long, angled on the back; de­pressed hilum much smaller than in Frailea cataphracta.
Type locality: Not cited. Distribution: Paraguay and Argentina.

Fig. 223.—Frailea pumila.

This species, the first of the group to be described, is not even now very well understood. The description of the seeds given above is drawn from Dr. Shafer's plant from Concordia, Argentina (No. 125) ; he notes that it grows in gravel and, being inconspicuous, is hard to find.
In 1920 Dr. C. Fiebrig, Director of the Botanical Garden at Asuncion, Paraguay, sent us a fine specimen; it is very cespitose, with 20 heads or more, forming a low mound nearly 10 cm. in diameter.
Illustrations: Knippel, Kakteen pl. 8; Monatsschr. Kakteenk. 9: 55, C, as Echinocactus pumilus.
Figure 223 shows a potted plant sent by Dr. Fiebrig in 1920 (No. 7).

4. Frailea schilinzkyana (Haagejr.).

Echinocactus schilinzkyanus Haage jr. in Schumann, Monatsschr. Kakteenk. 7: 108. 1897.
Cactus schilinzkyanus Kuntze, Deutsch. Bot. Monatsschr. 21: 193. 1903.

Simple or somewhat cespitose, usually globular, somewhat flattened above, about 3 cm. in diameter, but umbilicate at apex; ribs 10 to 13, but very indistinct, more or less spiraled, strongly tubercled; radial spines 12 to 14, 2 to 3 mm. long, more or less appressed and reflexed; central spine solitary, stouter than the radials; flowers small, often cleistogamous; fruit yellowish.
Type locality: Meadows near the River Paraguari, Paraguay.
Distribution: Paraguay; also Argentina, according to Spegazzini.
Nicholson (Dict. Gard. Suppl. 336. 1900) states that "this may be a Mammillaria."
Echinocactus schilinzkyanus grandiflorus Haage jr. (Monatsschr. Kakteenk. 8: 143. 1898) is only mentioned.
Illustrations: Cact. Journ. 1: 45; Schelle, Handb. Kakteenk. 183. f. 117; Schumann, Gesamtb. Kakteen Nachtr. f. 21; Monatsschr. Kakteenk. 9: 55, D, as Echinocactus schilinz­kyanus.

5. Frailea cataphracta (Dams).

Echinocactus cataphractus Dams, Monatsschr. Kakteenk. 14: 172. 1904.

Small, globose plants, 1 to 2 cm. in diameter, deeply umbilicate at apex, simple or sometimes pro­liferous, dull green; ribs low and broad, 10 to 15; tubercles flattened above, each with a purple lunate band near the margin; radial spines 5 to 9, straight, 1 to 2 mm. long, appressed, yellowish or white; central spines none; flowers evidently minute, but unknown; fruit small; seeds comparatively large, 2 mm. broad.
Type locality: Described from greenhouse plants. Supposed to have come from Paraguay.
Distribution: Paraguay.
Seeds planted November 24, 1912, developed into plants which flowered in March 1915. In the case of a plant which fruited in 1914 the seeds were carried away by ants and were found germinating in the sand in March 1915.

6. Frailea pygmaea (Spegazzini).

Echinocactus pygmaeus Spegazzini, Anal. Mus. Nac. Buenos Aires III. 4: 497. 1905.

Simple or cespitose, half buried in the ground, globose, umbilicate at apex, with a turbinate base, 1 to 3 cm. in diameter, dull green; ribs 13 to 21, obtuse, low, divided by transverse depression into tubercles; spines 6 to 9, white, setaceous, 1 to 4 mm. long, appressed; flowers from the apex of the plant, often cleis­togamous, with dense, rose-colored pubescence without, 2 to 2.5 cm. long; inner perianth-segments lance­olate, acute, yellow; filaments and style white; stigma-lobes yellowish; seeds 2 mm. long, black, shining, with a large oblong hilum nearly as long as the body.
Type locality: Mountains about Montevideo, Uruguay. Distribution: Uruguay and province of Entre Rios, Argentina.
Echinocactus pygmaeus phaeodiscus (Spegazzini, Anal. Mus. Nac. Buenos Aires III. 4:498. 1905) is similar to the type, but has lower ribs, blackish areoles, and 6 to 12 spines from an areole; flowers said to be like those of the type. It also suggests Frailea cataphracta.
We obtained a flower and seeds of this species from Dr. Spegazzini and have also ex­amined a sketch made by him.
Illustration: Anal. Mus. Nac. Montevideo 5: pl. 17, as Echinocactus pygmaeus.

7. Frailea caespitosa (Spegazzini).

Echinocactus caespitosus Spegazzini, Anal. Mus. Nac. Buenos Aires III. 4: 495. 1905.

Simple or densely cespitose, half buried in the ground; separate plants small, turbinate to clavate or even oblong, 4 to 7 cm. long, 1.5 to 4.5 cm. in diameter, deeply umbilicate at apex; ribs 11 to 22, low, obtuse, 4 to 5 mm. broad, somewhat crenate; areoles orbicular to short-elliptic, 3 to 4 mm. apart; radial spines 9 to 11, setaceous, appressed, yellowish, very short, 3 to 6 mm. long; central spines 1 to 4, unequal, more or less curved, the longest one 10 to 15 mm. long; flowers small, 3.5 to 4 cm. long; inner perianth-segments yellow, lanceolate, acute; filaments yellow; style white; stigma-lobes purplish violet; axils of scales on ovary and flower-tube densely gray-tomentose and setose.
Type locality: Mountains near Montevideo. Distribution: Uruguay.

8. Frailea knippeliana (Quehl).

Echinocactus knippelianus Quehl, Monatsschr. Kakteenk. 12: 9. 1902.

Simple, small, cylindric, 6 cm. high, 2 cm. in diameter; ribs 15, low, divided into tubercles; spines about 16, yellowish; flowers 2.5 cm. long, yellowish; wool in the axils of the flower-scales long, white; seed 1.5 cm. long.
Type locality: Paraguay.
Distribution: Paraguay.
We know this species from descriptions and illustrations and from a single flower sent by L. Quehl in 1912.
Quehl and Schumann place it near Echinocactus gracillimus.
Illustrations: Knippel, Kakteen pl. 8; Schelle, Handb. Kakteenk. f. 118, as Echinocactus knippelianus