138 FLORA OF JAMAICA Altemanthera 



8. ALTERNANTHERA Forsk. 



Herbs, often somewhat woody below, usually prostrate or 

 decumbent. Leaves opposite. Flowers small, hermaphrodite, 

 capitate. Heads sessile (in Jamaican species), axillary, solitary, 

 or 2 or 3 clustered. Bract flat, sliorter than exterior lateral 

 perianth-segments, bracteoles concave. Perianth with 5 unequal 

 segments, two exterior flattened, median flattened, shorter, two 

 lateral interior concave, still shorter. Stamens 3—5 ; filaments 

 united into a short cup at base, with alternating staminodes ; 

 anthers 1 -celled. Ovary with one ovule pendulous at the end of 

 a long stalk. Utricle compressed, roundish to obcordate. Seed 

 with annular embryo. 



Species 70, natives of tropics and subtropics, especially of 

 America. 



Leaves of a pair very unequal. 



Leaves obovate-rhomboid, unequal-sided. Exterior 

 perianth-segments villose at base only or 



glabrate 1. A.repens. 



Leaves mostly elliptical, equal-sided. Exterior 



perianth-segments villose 2. A. par vi folia. 



Leaves of a pair, more or less equal. 



Perianth mucronate or spiny 3. A. ficoidea. 



Perianth not mucronate nor spiny, though some- 

 times slightly mucronulate. 

 Perianth 2 mm. 1., exterior segments 1-ribbed, 



glabrous. Utricle longer than perianth 4. A, sessilis. 



Perianth i mm. 1., exterior segments S-ribbed 



and hirsute below 5. A. paronychioides, 



1. A. repens Kuntze Bev. ii. 540 (1891); leaves obovate- 

 rhomboid or obovate-elliptical, unequal-sided, obtuse, one of a pair 

 larger than the other ; two exterior segments of perianth strongly 

 acuminate-spiny, with three strong nerves, and short hairs near 

 base or glabrate; hairs minutely barbed at apex. — Urh. Symh. 

 Ant. iv. 221 (in part). A. Achyrantha Moq. in DC. Prodr. xiii. 

 pt. 2, 358 (1849) ; Griseh. Fl. Br. W. Ind. 67 (in part). Achy- 

 ranthes repens L. Sp. PI. 205 (1753). lUecebrum Achyrantha 

 L. Sp. PL ed. 2, 299 (1762). 



A prostrate weed on sides of streets, Spanish Town, Hairis d liritton 1 

 Fl. Jam. 10,517. — Florida, Central and S. America, west trop. Africa. 



Stem pubescent-villose. Leaves mucronate, with a few hairs near the 

 base or glabrate, larger 1-5-2-5 cm. 1., 1-1*5 cm. br., smaller •7--8 cm. 1. 

 Heads 7-12 mm. 1. Bracts glabrous, lanceolate with spiny apex, a little 

 shorter than exterior perianth-segments and a little longer than bracteoles. 

 Flowers straw-coloured. Perianth-segjnents, two exterior 4-5 mm. 1., 

 lanceolate, median elliptical, obtuse, mucronate, with short hairs below, 

 about 3 mm. 1. ; interior 2-5 mm. 1., bearded just above the middle but 

 not to the apex. Stamens 5, about 1 mm. 1. ; staminodes in form of 

 short teeth; cup "25 mm. 1. Utricle 1*5 mm. 1., roundish, somewhat 

 truncate at apex. Seed 1*8 mm. 1., round, compressed. 



