Dear friends The confusion between Senna pallida (Cassia biflora L.) perhaps not as simple as we thought. The confusion started with several websites treating two as synonyms, giving the impression that perhaps two are very close and as such we have separated many plants with shrubby habit and lesser number of leaflets as Senna pallida and one more or less tree like habit and more than 7 leaflets as Senna polyphylla.
After going though various reliable sources I came to know than Senna polyphylla is very distinct from Senna pallida. *Senna pallida (syn Cassia biflora L.)* Small shrub up to 3.5 m tall, stems slender; leaf stalk with two orange dots on petiole, base of petiole and leaflets swollen at base; leaf 5-6 cm long, leaflets 4-7 pairs, 2-3 cm long, 1.5 cm broad, widest near apex, base and apex rounded, veins obscure; flowers bright yellow , 3 cm across, in pairs on 2 cm long pedecels; fruit dry, flattened, 6-8 cm long, 3-5 mm broad, repeated x pattern on surface. http://www.desert-tropicals.com/Plants/Fabaceae/Cassia_biflora.html http://intermountainbiota.org/portal/taxa/index.php?taxon=28361 http://books.google.co.in/books?id=e-d0p54_KSYC&pg=PT401&lpg=PT401&dq=Cassia+biflora+plants+of+costa+rica&source=bl&ots=9oPAXTbp-8&sig=LNWZlrVykQZzXGuNO3kAr8Jr3jM&hl=en&ei=XoXkToOhJMnQrQfknfiDCA&sa=X&oi=book_result&ct=result&resnum=4&sqi=2&ved=0CDsQ6AEwAw#v=onepage&q&f=false Senna polyphylla: Desert cassia Shrub or small tree: often 5 m tall; leaves often clustered 3-5 together at each node; leaflets 3-15 pairs, 5-10 mm long; flowers yellow 3.8 cm across, axillary racemes of two flowers; pod 8-15 cm long, slightly contorted, flattened between seeds. http://www.fs.fed.us/global/iitf/pdf/shrubs/Senna%20polyphylla.pdf http://commons.wikimedia.org/wiki/Category:Senna_polyphylla Looking at smaller size of leaflets and leaves more or clustered it appears that photographs uploaded recently under both names actually all belong to Senna polyphylla and we may have to still locate true specimens of Senna pallida like we are still looking for Senna surattensis. Your views onj this please -- Dr. Gurcharan Singh Retired Associate Professor SGTB Khalsa College, University of Delhi, Delhi-110007 Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. Phone: 011-25518297 Mob: 9810359089 http://people.du.ac.in/~singhg45/
