14 



The cactaceae. 



3. NEOLLOYDIA Britton and Rose, Bull. Torr. Club 49: 251. 1922. 



Small, more or less cespitose cacti, fibrous-rooted, cj^lindric, densely spin}', tubercled; tubercles 

 more or less arranged on spiraled ribs, grooved above; radial spines numerous, widely spreading; 

 central spines one to several, much stouter and longer than radials; flowers large, pink or purple, 

 subcentral from axils of nascent tubercles, their segments widely spreading; fruit compressed- 

 globose, dull-colored, thin-walled, becoming paperi,^ dry, with few scales or none; seeeds globose, 

 black, dull, tuberculate-roughened, with a large white basal scar; embrv'o straight in typical species. 



Type species: ^lammillaria conoidca De CandoUe. 



We recognize 7 species from central and northern Mexico and Texas, which have been 

 transferred from Echinocacins and MammiUaria. The genus is dedicated to Professor 

 Francis E. Lloyd, whose collections and observations have contributed highly important 

 information to our investigations. 



Key to Species. 



Plants 3 cm. in diameter or less; central spines sometimes wanting i. N. pilispina 



Plants larger; central spines always present. 



Central spines cur^-ed or hooked 2 . N. clavaia 



Central spines all straight. 

 Central spine solitary. 



Central spine stiff, porrect 3 . N. horripila 



Central spine weak, ascending or connivent 4. N. beguinii 



Central spines several. 



Spines white or sometimes dark above 5 . N. ceratites 



Central spines or some of them black. 



Radial spines 25 or more; Mexican species 6. N. conoidea 



Radial spines 15 or less 7. ^V. iexensis 



1. NeoUoydia pilispina (J. A. Purpus). 



Mammillarm pilispina J. A. Purpus, Monatsschr. Kakteenk. 22: 150. 1912. 



Plants cespitose, about 3 cm. in diameter; ribs indistinct, made up of very definite, somewhat 

 angled tubercles young spine-areoles clothed with abundant, long, white wool covering top of 



Fig. 12. — NeoUoydia pilispina. 



Fig. 13. — NeoUoydia horripila. 



plant; radial spines 6 or 7, 5 to 6 mm. long, weak and spreading, the upper ones longer and connivent 

 over top of plant, 2 cm. long or more, white with blackish tips ; central spines often %vanting, some- 

 times one; flowers small, 1.5 to 2 cm. long, piu'plish; outer perianth-segments brownish. 



Type locality: Minas de San Rafael, San Luis Potosi, Mexico. 



Distribution: Known only from the type locality. 



Figure 12 is from a photograph of a plant collected by C. A. Purpus at the t3'pe locality. 



