Mukula means a Bud. When all the five finger are brought together and touch each other at the tip, we get the Mukula hasta.

Lets see what the viniyaga shloka has to say :
kumude bhojane panchabane mudradidharane
nabhao cha kadalipushpe yujyate mukulah karaha
This sloka talks about the various uses of Mukula. It can denote the following :

A [...]

When both the palms in Pataka are joined together we get the Anjali Mudra. In fact in the Indian culture this Mudra is very often used for greeting people.

Viniyoga shloka (in sanskrit) and the meaning :
Devataguruvipranam namaskareshavanukramat
karyaha shiromukhorastho viniyoganjalirbudhaihi
This mudra is used to offer salutation to the God, Elders, Teachers and a Brahmin. The Anjali [...]