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SE Biology , Vol. 61, No. 1, January, 2014 
INVITED RESEARCH PAPER 
Rain-lilies (Amaryllidaceae) of U.S.A. and Mexico 
Raymond O. Flagg 
Carolina Biological Supply Company 
2015 Muirfield Court, Elon NC 27244 
rflagg@triad.rr.com 
Rain-lilies are perennial amaryllids, scapose, from black or brown tunicate, ovoid 
to globose bulbs, sometimes with long neck. The leaves are deciduous or rarely 
perennial, sessile, erect or recumbent, with overlapping sheathing bases, 
smooth; blade linear, rarely exceeding 2 cm wide. The scape is hollow and 
leafless. Inflorescences are umbellate, 1 [--4]-flowered, spathaceous; spathe 
proximally tubular; bracteoles sometimes present in Habranthus. Flowers are 
erect to declinate; perianth 6-parted, connate basally into a tube 2--16 cm; style 
filiform; stigma 3-fid, linear (or capitate in some Zephyranthes). Fruits are 
capsular, thin-walled, 3-loculicidal, and globose to 3-lobed, pedicellate or sessile. 
Seeds numerous, dark brown to black, lustrous, flat, and D-or wedge shaped. 
I use the common name rain-lilies because there has long been obfuscation 
about generic boundaries in the tribe Zephyrantheae. Generic names associated 
with rain-lilies include: Agryropsis, Arviela, Atamasco, Cooperia, Habranthus, 
Haylockia, Mesochloa, Plectronema, Pogonema, Screptranthes, Zephyranthes, 
and Zephyrites. The names Zephyranthes (including Cooperia) and Habranthus 
are currently in use. Habranthus has been included in Zephyranthes by Bentham 
and Flooker (1883), Baker (1888), Pax (1888), and Hutchinson (1934, 1959). 
Habranthus and Zephyranthes have been treated as a distinct genera by Herbert 
(1837), Stapf (1927), Sealy (1937), Traub (1952), and Flagg, Smith and Flory 
(2002a). 
Zephyranthes is distinguished from Habranthus (Fig. 1) by upright anthers 
(generally nearly parallel to the filaments) with little curvature, if any. Habranthus 
is distinguished by horizontal anthers (generally perpendicular to the filaments) 
with usually notable curvature (often lunate) (Flagg, Smith and Meerow, 2010). 
DNA studies [Meerow et al., 2000; G.L. Smith and his students (Spurrier and 
Smith, 2011 and ongoing research)], indicate that (1) Zephyranthes is 
polyphyletic, (2) Zephyranthes of SE USA and South America, and Zephyranthes 
of Mexico and SW USA are in different clades and (3) Zephyranthes of Mexico 
and SW USA may be more closely related to Habranthus than to Zephyranthes 
of SE USA and South America. 
Sometimes it seems as though I have studied rain-lilies my whole life. 
Actually, I did not see a rain-lily until I was 24-years old, and was being 
interviewed by Dr. Walter S. Flory, Jr. (deceased, 8 Jun 1998). I was naive to the 
professional world of biology. I did not know that I was being interviewed by an 
eminent biologist, nor did I realize what it meant to be accepted as a student of 
Professor Flory (Flagg and Smith, 1999). To my great fortune, I became 
Research Assistant to Dr. Flory in June 1957 at The Blandy Experimental Farm 
near Boyce, Virginia, and his graduate student at the University of Virginia. 
